Antioxidants for Male Sub Fertility (Review)

Antioxidants for male subfertility (Review)

Showell MG, Brown J, Yazdani A, Stankiewicz MT, Hart RJ

This is a reprint of a Cochrane review, prepared and maintained by The Cochrane Collaboration and published in The Cochrane Library2011, Issue 6

http://www.thecochranelibrary.com

Antioxidants for male subfertility (Review)

Copyright © 2011 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.

http://www.thecochranelibrary.com

T A B L E O F C O N T E N T S

1HEADER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1ABSTRACT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2PLAIN LANGUAGE SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2SUMMARY OF FINDINGS FOR THE MAIN COMPARISON . . . . . . . . . . . . . . . . . . .

5BACKGROUND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6OBJECTIVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6METHODS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

9RESULTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Figure 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Figure 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Figure 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Figure 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Figure 6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Figure 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Figure 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Figure 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Figure 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Figure 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Figure 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Figure 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Figure 14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Figure 15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Figure 16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Figure 17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Figure 18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Figure 19. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Figure 20. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Figure 21. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Figure 22. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Figure 23. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

38DISCUSSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Figure 25. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

41AUTHORS’ CONCLUSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

41ACKNOWLEDGEMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

42REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

46CHARACTERISTICS OF STUDIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

91DATA AND ANALYSES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Analysis 1.1. Comparison 1 Antioxidant(s) versus control, Outcome 1 Live Birth per couple randomised. . . . . 98

Analysis 1.2. Comparison 1 Antioxidant(s) versus control, Outcome 2 Pregnancy rate per couple randomised. . . . 99

Analysis 1.3. Comparison 1 Antioxidant(s) versus control, Outcome 3 Adverse event: Miscarriage rate per couple

randomised. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

Analysis 1.4. Comparison 1 Antioxidant(s) versus control, Outcome 4 DNA fragmentation. . . . . . . . . . 102

Analysis 1.5. Comparison 1 Antioxidant(s) versus control, Outcome 5 Sperm total motility at 3 months or less. . . 102

Analysis 1.6. Comparison 1 Antioxidant(s) versus control, Outcome 6 Sperm total motility at 6 months. . . . . 105

Analysis 1.7. Comparison 1 Antioxidant(s) versus control, Outcome 7 Sperm total motility at 9 months or more. . 106

Analysis 1.8. Comparison 1 Antioxidant(s) versus control, Outcome 8 Sperm concentration at 3 months or less. . . 107

Analysis 1.9. Comparison 1 Antioxidant(s) versus control, Outcome 9 Sperm concentration at 6 months. . . . . 109

Analysis 1.10. Comparison 1 Antioxidant(s) versus control, Outcome 10 Sperm concentration at 9 months or more. 110

Analysis 1.11. Comparison 1 Antioxidant(s) versus control, Outcome 11 Total sperm motility over time. . . . . 111

iAntioxidants for male subfertility (Review)


Analysis 1.12. Comparison 1 Antioxidant(s) versus control, Outcome 12 Sperm concentration over time. . . . . 113

Analysis 1.13. Comparison 1 Antioxidant(s) versus control, Outcome 13 Side effects. . . . . . . . . . . . 114

Analysis 1.18. Comparison 1 Antioxidant(s) versus control, Outcome 18 Pregnancy. . . . . . . . . . . . . 117

Analysis 2.1. Comparison 2 Live birth versus pregnancy, Outcome 1 Live birth. . . . . . . . . . . . . . 118

Analysis 3.1. Comparison 3 Head to head antioxidant(s), Outcome 1 Pregnancy per couple randomised. . . . . 119

Analysis 3.2. Comparison 3 Head to head antioxidant(s), Outcome 2 Sperm total motility at 3 months or less. . . 120

Analysis 3.3. Comparison 3 Head to head antioxidant(s), Outcome 3 Sperm total motility at 6 months. . . . . . 121

Analysis 3.4. Comparison 3 Head to head antioxidant(s), Outcome 4 Sperm total motility at 9 months or more. . . 122

Analysis 3.5. Comparison 3 Head to head antioxidant(s), Outcome 5 Sperm concentration at 3 months or less. . . 123

Analysis 3.6. Comparison 3 Head to head antioxidant(s), Outcome 6 Sperm concentration at 6 months. . . . . . 124

Analysis 3.7. Comparison 3 Head to head antioxidant(s), Outcome 7 Sperm concentration at 9 months or more. . . 125

Analysis 3.8. Comparison 3 Head to head antioxidant(s), Outcome 8 Side effects. . . . . . . . . . . . . 125

126APPENDICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

135WHAT’S NEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

135HISTORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

135CONTRIBUTIONS OF AUTHORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

135DECLARATIONS OF INTEREST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

136SOURCES OF SUPPORT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

136DIFFERENCES BETWEEN PROTOCOL AND REVIEW . . . . . . . . . . . . . . . . . . . . .

136INDEX TERMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

iiAntioxidants for male subfertility (Review)


[Intervention Review]

Antioxidants for male subfertility

Marian G Showell1, Julie Brown1 , Anusch Yazdani2, Marcin T Stankiewicz3 , Roger J Hart4

1Obstetrics and Gynaecology, University of Auckland, Auckland, New Zealand. 2Clinical Research and Development, Queensland

Fertility Group, Woolloongabba, Australia. 3Reproductive Medicine, Flinders Reproductive Medicine, Bedford Park, Australia. 4School

of Women’s and Infants Health, The University of Western Australia, King Edward Memorial Hospital and Fertility Specialists of

Western Australia, Subiaco, Australia

Contact address: Marian G Showell, Obstetrics and Gynaecology, University of Auckland, Park Road Grafton, Auckland, New Zealand.

[email protected].

Editorial group: Cochrane Menstrual Disorders and Subfertility Group.

Publication status and date: Edited (no change to conclusions), published in Issue 6, 2011.

Review content assessed as up-to-date: 21 August 2010.

Citation: Showell MG, Brown J, Yazdani A, Stankiewicz MT, Hart RJ. Antioxidants for male subfertility. Cochrane Database ofSystematic Reviews 2011, Issue 1. Art. No.: CD007411. DOI: 10.1002/14651858.CD007411.pub2.


A B S T R A C T

Background

Between 30% to 80% of male subfertility cases are considered to be due to the damaging effects of oxidative stress on sperm. Oral

supplementation with antioxidants may improve sperm quality by reducing oxidative stress.

Objectives

This Cochrane review aimed to evaluate the effect of oral supplementation with antioxidants for male partners of couples undergoing

assisted reproduction techniques (ART).

Search strategy

We searched the Cochrane Menstrual Disorders and Subfertility Group Register, CENTRAL (The Cochrane Library), MEDLINE,

EMBASE, CINAHL, PsycINFO and AMED databases (from their inception until Febuary 2010), trial registers, sources of unpublished

literature, reference lists and we asked experts in the field.

Selection criteria

We included randomised controlled trials comparing any type or dose of antioxidant supplement (single or combined) taken by the

male partner of a couple seeking fertility assistance with placebo, no treatment or another antioxidant. The outcomes were live birth,

pregnancy, miscarriage, stillbirth, sperm DNA damage, sperm motility, sperm concentration and adverse effects.

Data collection and analysis

Two review authors independently assessed studies for inclusion and trial quality, and extracted data.

Main results

We included 34 trials with 2876 couples in total.

Live birth: three trials reported live birth. Men taking oral antioxidants had an associated statistically significant increase in live birth

rate (pooled odds ratio (OR) 4.85, 95% CI 1.92 to 12.24; P = 0.0008, I2 = 0%) when compared with the men taking the control.

This result was based on 20 live births from a total of 214 couples in only three studies.

1Antioxidants for male subfertility (Review)


mailto:[email protected]

Pregnancy rate: there were 96 pregnancies in 15 trials including 964 couples. Antioxidant use was associated with a statistically significant

increased pregnancy rate compared to control (pooled OR 4.18, 95% CI 2.65 to 6.59; P < 0.00001, I2 = 0%).

Side effects: no studies reported evidence of harmful side effects of the antioxidant therapy used.

Authors’ conclusions

The evidence suggests that antioxidant supplementation in subfertile males may improve the outcomes of live birth and pregnancy

rate for subfertile couples undergoing ART cycles. Further head to head comparisons are necessary to identify the superiority of one

antioxidant over another.

P L A I N L A N G U A G E S U M M A R Y

Antioxidants for male subfertility

Oxidative stress may cause sperm cell damage. This damage can be reduced by the body’s own natural antioxidant defences. Antioxidants

can be part of our diet and taken as a supplement. It is believed that in many cases of unexplained subfertility, and also in instances

where there may be a sperm-related problem, taking an oral antioxidant supplement may increase a couple’s chance of conceiving when

undergoing fertility treatment. This review identified 34 randomised controlled trials involving 2876 couples. Pooled findings support

increases in live births and pregnancy rates with the use of antioxidants by the male partner. Further work is recommended to confirm

these findings.



S U M M A R Y O F F I N D I N G S F O R T H E M A I N C O M P A R I S O N [Explanation]

Antioxidant/s versus control for male subfertility

Patient or population: patients with male subfertility

Settings:

Intervention: Antioxidant/s versus control

Outcomes Illustrative comparative risks* (95% CI) Relative effect

(95% CI)

No of Participants

(studies)

Quality of the evidence

(GRADE)

Comments

Assumed risk Corresponding risk

Control Antioxidant/s versus

control

Live Birth per couple

randomised

Follow-up: 6 - 24 months

20 per 1000 90 per 1000

(38 to 200)

OR 4.85

(1.92 to 12.24)

214

(3 studies)

⊕⊕©©

low1,2

Pregnancy rate per cou-

ple randomised

Follow-up: 3-24 months

31 per 1000 118 per 1000

(78 to 174)

OR 4.18

(2.65 to 6.59)

964

(15 studies)

⊕⊕⊕©

moderate3

Adverse event: Miscar-

riage rate per couple

randomised

Follow-up: 6-18 months

19 per 1000 29 per 1000

(6 to 124)

OR 1.54

(0.32 to 7.3)

242

(3 studies)

⊕⊕⊕©

moderate4

Total spermmotility over

time - Total sperm motil-

ity at 3 months or less

Follow-up: 4-24 weeks

The mean Total sperm

motility over time - To-

tal sperm motility at 3

months or less in the in-

tervention groups was

13.47 higher

(3.45 to 23.49 higher)

454

(10 studies)

⊕©©©

very low5,6

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Sperm

concentration over time

- Sperm concentration at

3 months or less

Follow-up: 4-36 weeks

The mean Sperm con-

centration over time -

Sperm concentration at 3

months or less in the in-

tervention groups was

6.79 higher

(5.09 lower to 18.66

higher)

302

(7 studies)

⊕©©©

very low7,8

*The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the

assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).

CI: Confidence interval; OR: Odds ratio;

GRADE Working Group grades of evidence

High quality: Further research is very unlikely to change our confidence in the estimate of effect.

Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.

Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.

Very low quality: We are very uncertain about the estimate.

1 The trials lacked adequate explanation for methods of randomisation, allocation concealment and blinding2 wide confidence intervals3 Only 6 trials gave adequate explanation for randomisation and allocation concealment4 Total number of events = 75 Very high heterogeneity and remained high after sensitivity analysis6 Wide confidence intervals7 Very high heterogeneity8 Wide confidence intervals

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B A C K G R O U N D

Description of the condition

Eighty million people worldwide are affected by the inability to

have children (Tournaye 2006). Delayed conception affects 15%

of couples trying to conceive (Attia 2007) and male factor subfer-

tility accounts for up to 50% of these cases. A review by Tremellen

(Tremellen 2008) notes that one man in 20 will be affected by

subfertility.

Some 30% to 80% of male factor subfertility cases are said to be

due to the damaging effects of oxidative stress (Tremellen 2008).

Oxidative stress occurs when reactive oxygen species (ROS) over-

come the semen’s natural antioxidant defences and cause cellular

damage (Tremellen 2008). Some studies have suggested that sperm

production and quality has decreased over the past few decades

(Stankiewicz 2003). The increased levels of ROS are thought to be

due to environmental factors such as high temperatures, electro-

magnetic radiation, pesticides and pollution; and lifestyle factors

of advanced age, alcohol consumption, smoking, stress, obesity

and poor diet. Other factors include infections, autoimmunity and

chronic disease (Aitken 2007; Alvarez 2003; Tremellen 2008).

Spermatozoal membranes are rich in poly-unsaturated fatty acids

and are susceptible to oxygen damage from lipid peroxida-

tion (Sheweita 2005). Abnormal spermatozoa and contaminating

leukocytes generate ROS (Sikka 1995).

Antioxidants that are naturally found in semen include vitamins E

and C, superoxide dismutase, glutathione and thioredoxin (Omu

2008). These antioxidants act as free radical scavengers that help

to overcome ROS. Subfertile men have been identified as hav-

ing lower levels of antioxidants in their semen compared to fertile

men (Tremellen 2007). A study by Bykova (Bykova 2007) showed

that ROS levels were significantly higher in infertile sperm sam-

ples when compared with healthy controls and that the infertile

men who provided these samples may benefit from an antioxidant

supplement.

ROS are thought to cause fertility problems in two ways, firstly by

damaging the sperm membrane thus affecting the sperm motil-

ity and the ability of the spermatozoa to break down the oocyte

membrane; and secondly by altering the sperm DNA. Spermato-

zoal DNA integrity is one of the major determinants of normal

fertilisation and embryo growth in natural and assisted conception

(Agarwal 2003; Aitken 2004; Tarozzi 2007). Indeed, many men

with normal seminal parameters may have a high degree of sperm

DNA damage and this correlates with a poor chance of natural

conception (Boe-Hansen 2006).

Sperm DNA damage or integrity can be assessed in a number of

ways. These include sperm chromatin structural assay by flow cy-

tometry (SCSA); enzymatic labelling of broken DNA strands, the

terminal deoxynucleotide transferase-mediated nick end-labelling

assay (TUNEL); and microscopic observations of DNA fragments,

the Comet assay. The greatest experience with and standardisa-

tion of exists for the SCSA (Aitken 2007; Evenson 2007). Indeed

there are advocates who state that this should be part of a stan-

dard assessment of the male partner when a couple presents with

subfertility (Boe-Hansen 2006); although it is recognised that the

technique has its limitations and hence strict laboratory control

and standardisation is required (Boe-Hansen 2005).

Sperm DNA fragmentation does not appear to influence fertilisa-

tion in in vitro fertilisation (IVF), although a negative correlation

of sperm DNA damage with embryo or blastocyst development has

been described (Evenson 2006; Li 2006; Tarozzi 2007). Women

undergoing intrauterine insemination with a sperm DNA frag-

mentation index < 30%, as measured by the SCSA, are seven times

more likely to achieve a pregnancy than those couples where the

male partner had a higher degree of sperm DNA damage (Evenson

2006). The evidence for the effect of a high degree of sperm DNA

damage upon pregnancy outcome is less clear. A meta-analysis of

sperm DNA fragmentation assessed by the SCSA determined that

if the sperm DNA fragmentation was < 30% the couple were twice

as likely to conceive in an IVF cycle than if it was greater than 30%,

though the evidence for a benefit in women undergoing intra-

cytoplasmic sperm injection (ICSI) was unclear (Evenson 2006).

However, a meta-analysis of SCSA papers published in the same

year demonstrated conflicting results (Li 2006). This meta-analy-

sis found that there was no effect of sperm DNA damage assessed

by the SCSA assay upon the outcome of IVF or ICSI (Li 2006).

The meta-analysis also reviewed the effect of sperm DNA damage

as assessed by the TUNEL assay. This demonstrated a reduced

pregnancy rate in women undergoing IVF when the male partner

had a high degree of sperm DNA damage, but no difference if they

were undergoing ICSI (Li 2006). It also appears that miscarriage

is more likely in women undergoing assisted reproduction when

the sperm DNA damage is high (Borini 2006).

Description of the intervention

Antioxidants are both biological (enzymes) and chemical sub-

stances that reduce oxidative damage. The chemical antioxidants

are both natural and synthetic. These can be derived from nutri-

tional sources and from supplementation (Sikka 1995). The pre-

dominant supplementary antioxidants that are studied in male

subfertility clinical trials are vitamin E, vitamin C, carotenoids,

ubiquinol and the micronutrients folate and zinc (Eskenazi 2005).

A paper by Tremellen (Tremellen 2008) discussed the use of a

combination of vitamins and minerals to improve pregnancy rates

for subfertile men.

Polyunsaturated fatty acids (PUFAs) are sources of antioxidants

and are commonly taken in the community as nutritional supple-

ments. PUFAs have varying effects in male fertility. They provide

antioxidants and also increase the plasma fluidity of the sperm

membrane which acts to assist with conception, however this fluid-

ity makes the sperm susceptible to reactive oxygen species and lipid

peroxidation that can damage the sperm (Wathes 2007). Wathes

states that “It appears that PUFAs are a two edged sword - some



are essential, but too many are potentially harmful” (Wathes 2007,

page198). An open study by Comhaire attempted to overcome

the double edged sword of essential fatty acid supplements by also

treating the subfertile men in their study with antioxidant sup-

plements of acetyl cysteine or beta-carotene and alpha-tocopherol

(Comhaire 2000).

PUFAs are classified into omega-3, omega-6 and omega-9.

Omega-9 is synthesised by animals but omegas-3 and 6 need to be

supplemented in the diet. The main sources of omega-6 are veg-

etable oils. Sources of omega-3 are vegetable and fish oils (Wathes

2007).

Antioxidants are widely available and inexpensive when compared

to other fertility treatments however this review did not include

any cost benefit analysis.

How the intervention might work

Antioxidants are known to scavenge and dispose of ROS, suppress

their formation and also act to oppose the actions of ROS (Sikka

1995). The dietary intake of antioxidants has been shown to be

critically important for semen quality. Some clinical trials of an-

tioxidant supplementation have shown an associated increase in

fertilisation rates, possibly by reducing oxidative stress, lipid per-

oxidation potential and ROS levels (Eskenazi 2005).

Why it is important to do this review

Currently there is limited evidence that antioxidant supplemen-

tation improves outcomes for subfertile couples. Although some

clinical trials of supplemental antioxidants have suggested benefits

in treating male subfertility there are other trials that fail to demon-

strate the same benefit (Agarwal 2004). Tournaye (Tournaye 2006)

described the consensus on the treatment of unexplained male

subfertility with antioxidants as potentially beneficial but stated a

need for further evaluation. The purpose of this Cochrane review

was to assess the effects of antioxidants on men with documented

sperm DNA damage and men with impaired semen parameters

from appropriate clinical trials that use the clinically relevant pa-

rameters of live birth and pregnancy. The review also assessed the

effectiveness of different antioxidants and dosages on these out-

comes.

O B J E C T I V E S

The objective of this review was to determine whether supple-

mented oral antioxidants compared to placebo, no treatment or

another antioxidant improve outcomes for couples with a subfer-

tile male partner. Couples were undergoing assisted reproduction

technologies (ART) such as in vitro fertilisation (IVF), intrauterine

insemination (IUI) or intracytoplasmic sperm injection (ICSI).

The main questions asked in this review were whether:

1. supplemented oral antioxidants improve outcomes for couples

with male factor infertility or unexplained infertility who are un-

dergoing ART;

2. different types of antioxidants given to men have varying effects

in this setting.

M E T H O D S

Criteria for considering studies for this review

Types of studies

Inclusion criteria

• Only randomised controlled trials were eligible for

inclusion. The participants were randomised to antioxidant

versus placebo, an alternative antioxidant, or no treatment.

• Only pre-crossover data were used from randomised

crossover trials, as achieving outcomes such as pregnancy and live

birth precluded couples entering the next trial phase (Dias 2006).

Exclusion criteria

• Any quasi-randomised trials

Types of participants

Inclusion criteria

• Trials that included men who were part of a couple with

male factor subfertility or unexplained subfertility and who were

undergoing ART using their own gametes.

In situations where individuals were randomised again following

failed cycles the data would not be pooled in a meta-analysis unless

individual data could be excluded.

Exclusion criteria

• Trials that included men taking any other fertility

enhancing drugs

• Trials that included men who had had chemotherapy

treatment



Types of interventions

• Trials were included if they investigated any type of

chemical supplementary antioxidant

• Trials were included if they investigated individual or

combined antioxidants (including head to head comparisons)

• Any dose of antioxidant was included

• Trials using only the oral route of administration were

included

Types of outcome measures

Primary outcomes

• Live birth rate per couple randomised

Secondary outcomes

• Pregnancy rate per couple

• Miscarriage rate per couple, or spontaneous abortion

• Stillbirth rate per couple

• Level of sperm DNA damage after treatment

• Sperm concentration

• Sperm motility

• Adverse effects or side effects associated with antioxidant

supplementation, or as was reported by the trial. Withdrawal

numbers due to individual adverse effects were reported

Search methods for identification of studies

See the Cochrane Menstrual Disorders and Subfertility

Group (MDSG) for methods used in reviews, as stated in

their Module (http://www.mrw.interscience.wiley.com/cochrane/

clabout/articles/MENSTR/frame.html).

All reports that described randomised controlled trials of oral an-

tioxidant supplementation for subfertile men were to be found

using the following strategy.

Electronic searches

(1) The Menstrual Disorders and Subfertility Group Specialised

Register of controlled trials was searched by the Group’s Trial

Search Coordinator using the terms ’male subfertility’ or ’In vitro

fertilisation’ or ’IVF’ or ’Intracytoplasmic sperm injection’ or

’ICSI’ AND ’antioxidants’ or ’vitamin e’ or ’vitamin’ or ’ascorbic

acid’ or ’zinc’ or ’folate’ or ’selenium’ or ’glutathione’ or ’ubiquinol’

or ’carnitine’ or ’astaxanthin’ or ’coenzyme Q10’ or ’lycopene’ or

’Menevit’ or “carnitine” or “carnitine” or “ascorbic acid” or “zinc”

or “fatty acids” or “oil” or “fish oils” or “plant extracts” in the titles,

abstracts and keywords (from inception to 22.08.10) (Appendix

7).

This register also contains unpublished trial abstracts. These were

found by handsearching 20 relevant journals and conference pro-

ceedings.

(2) The following databases were searched using the Ovid plat-

form:

• Cochrane Central Register of Controlled Trials

(CENTRAL) (The Cochrane Library 2010, Issue 3) (Appendix 3);

• MEDLINE (inception to 22.08.10) (Appendix 1);

• EMBASE (2008 to 22.08.10) (Appendix 2);

• CINAHL (Cumulative Index to Nursing and Allied Health

Literature) (1980 to 22 August 2010) (Appendix 4);

• PsycINFO (inception to 22.08.10) (Appendix 5);

• AMED (Allied and Complementary Medicine) (inception

to 22 August 2010) (Appendix 6).

Both indexed and free text terms were used.

The MEDLINE search was combined with the Cochrane highly

sensitive search strategy for identifying randomised trials, which

appears in the Cochrane Handbook of Systematic Reviews of In-

terventions (Version 5.0.1 chapter 6, 6.4.11).

The EMBASE and CINAHL searches were combined with trial fil-

ters developed by the Scottish Intercollegiate Guidelines Network

(SIGN) (www.sign.ac.uk/mehodology/filters.html#random).

Searches were not limited to any one language.

Searching other resources

Appropriate journals were handsearched for trial conference ab-

stracts. These journals included ’Human Reproduction’ which

contains abstract supplements for the European Society of Hu-

man Reproduction and Embryology (ESHRE) and ’Fertility and

Sterility’ which contains abstract supplements for the ’American

Society for Reproductive Medicine’ (ASRM). Lists of journals

handsearched by the Menstrual Disorders and Subfertility Group

(MDSG) are found in the MDSG Module.

Research registers were searched for ongoing and recently com-

pleted trials:

• ’ClinicalTrials.gov’, a service of the US national Institutes of

Health (http://clinicaltrials.gov/ct2/home) (last searched 6

August 2010);

• ’The World Health Organization International Trials

Registry Platform search portal’ (www.who.int/trialsearch/

Default.aspx) (last searched August 2010).

Conference abstracts were found on the ISI Web of Knowledge:

http://isiwebofknowledge.com/ (last searched 6 August 2010).

OpenSIGLE database was searched for European grey literature:

http://opensigle.inist.fr/ (last searched 6 August 2010).

Citation lists from review articles and other relevant publications

were searched.

Personal communication with manufacturers, experts and special-

ists in the field.



http://www.sign.ac.uk/mehodology/filters.html#random



http://clinicaltrials.gov/ct2/home





http://www.who.int/trialsearch/Default.aspx



http://isiwebofknowledge.com/



http://opensigle.inist.fr/



Data collection and analysis

Selection of studies

Two people were responsible for independently selecting the tri-

als. Titles and abstracts from the searches were scanned. We ob-

tained the full text of those articles that appeared to be eligible

for inclusion. On assessment they were then placed in included

(Characteristics of included studies), excluded (Characteristics of

excluded studies), ongoing (Characteristics of ongoing studies)

studies or studies awaiting assessment (Characteristics of studies

awaiting classification). One of these individuals is a content ex-

pert. Any disagreements were resolved through consensus or by a

third party.

Studies were appraised in an unblinded fashion, as recommended

by the Cochrane Menstrual and Fertility Disorders Group. Further

information, where required, was sought from the authors

Data extraction and management

The studies that appeared to meet the inclusion criteria were in-

dependently assessed by the two review authors (MS and JB) us-

ing data extraction forms. Any discrepancies were resolved with

discussion.

The data extraction forms included methodological quality and al-

location information. This information was included in the review

and presented in the characteristics of included and excluded stud-

ies tables (see Characteristics of included studies; Characteristics of

excluded studies) following the guidance of the Cochrane Hand-

book for Systematic Reviews of Interventions (Higgins 2006).

Assessment of risk of bias in included studies

The included studies were assessed for risk of bias using the

Cochrane risk of bias assessment tool to assess: sequence genera-

tion; allocation concealment; blinding of participants, providers

and outcome assessors; completeness of outcome data; selective

outcome reporting; and other potential sources of bias. MS and JB

assessed these six criteria; any disagreements were resolved by con-

sensus or by discussion with a third author. The conclusions were

presented in the ’Risk of bias’ table (Characteristics of included

studies) and incorporated into the interpretation of review findings

by means of sensitivity analyses. Where identified studies failed to

report the primary outcome of live birth, but did report interim

outcomes such as pregnancy, informal assessment was undertaken

on whether those reporting the primary outcomes had typical val-

ues for the interim outcomes.

If other potential sources of bias were identified in advance, these

were specified and the number of criteria increased accordingly.

Sensitivity analyses were specified later, under the appropriate

heading.

The authors aimed to minimise reporting bias, publication bias,

within trial reporting bias and their potential impact by ensuring

that a comprehensive search for eligible studies was carried out.

Authors were also alert to duplication of data. As there were 10

or more studies in the analysis, a funnel plot was used to explore

the possibility of small study effects (a tendency for estimates of

the intervention effect to be more beneficial in smaller studies).

Care was taken to search for within study reporting bias, such

as trials failing to report obvious outcomes or reporting them in

insufficient detail to allow inclusion.

Measures of treatment effect

The dichotomous data for live birth, pregnancy rate, miscarriage,

stillbirth, and adverse events were expressed as odds ratios (OR)

with 95% confidence intervals (95% CI) and combined in a meta-

analysis with Rev Man software using the Peto method and a fixed-

effect model (Higgins 2006). The OR has mathematically sound

properties that are consistent with benefit or harm and work well in

small samples with rare events. This effect measure is appropriate

when considering subfertility. For continuous data (for example

sperm quality measurements) mean differences between treatment

groups were calculated with associated standard deviations and

95% confidence intervals. These were displayed on forest plots, if

possible.

Attempts were made to contact all authors of the included trials

that reported data in a form that was not suitable for meta-analysis,

for example data reported in medians or ranges. Where additional

data were not forthcoming the data were reported under ’other

data’ and not included in the meta-analysis.

Unit of analysis issues

The outcomes of live birth and pregnancy were analysed as per

couple randomised. The sperm outcomes analyses were per man

randomised. We included both parallel and crossover trials, using

only the first phase of the crossover trial.

Dealing with missing data

We attempted to contact the authors of the trials with any missing

data by email or post. If there was no reply, and if possible, we

reported the data in terms of intention to treat. If this was not

possible the trials were placed in ’studies awaiting assessment’.

Assessment of heterogeneity

The authors considered whether the clinical and methodological

characteristics of the included studies were sufficiently similar to

provide a meaningful summary in a meta-analysis.

Heterogeneity between the treatment effects of different studies

were studied by looking at the points on the forest plot, the overlap

of confidence intervals (a poor overlap indicates heterogeneity),

and the Chi2 statistical test for heterogeneity. A low P value (or a



large Chi2 statistic relative to its degree of freedom) shows evidence

of heterogeneity of treatment effects, or that the differences were

not likely to be by chance (Higgins 2006). If there was only a small

number of trials or they had small sample sizes then a P value of

0.10 rather than 0.05 was used to show heterogeneity. To more

formally quantify the variations between the studies the I2 statistic

was used (Higgins 2006). This statistic describes the variation in

effect estimates due to heterogeneity rather than by chance, as a

percentage. If a value over 50% was found we assumed that there

was large heterogeneity.

Assessment of reporting biases

If there was a question of publication bias, a funnel plot was drawn.

A gap on either side of the graph would have given a visual indi-

cation that some trials have not been identified (Higgins 2006).

This is often due to the difficulties in locating unpublished trials.

If there were outcomes with no data the review included empty

data tables. This indicates that further clinical trials need to be

conducted in this area. It also allows for updating, when new data

may be found.

Data synthesis

Statistical analysis of the data was carried out using Review Man-

ager 5 (RevMan 5). Pregnancy outcomes are considered positive

and higher numbers of pregnancy rates are considered a benefit.

The outcomes of miscarriage and adverse events are negative ef-

fects and higher numbers would be considered harmful. These

aspects have to be considered when assessing the summary graphs

(Attia 2007).

The data from primary studies were combined using a fixed-effect

model in the following comparisons.

1. Antioxidants versus control (placebo or no treatment), stratified

by type of antioxidant. Further analyses of sperm motility and

concentration were carried out by sub grouping trials over time: at

three, six and nine months. Subgrouping was also performed on

the outcomes of live birth and pregnancy. Trials that reported both

of these outcomes were subgrouped into live birth and pregnancy

in order to assess any overestimation of effect in the pregnancy

outcome. Subgrouping was also performed on those trials that

reported both live birth and pregnancy and trials that only reported

pregnancy in order to assess any reporting bias in the pregnancy

outcome.

2. Antioxidants versus antioxidants or head to head stratification

by type of antioxidant. An increase in the odds of a particular out-

come, which may be beneficial (for example live birth) or detri-

mental (for example adverse effects), were displayed graphically in

the meta-analyses to the right of the centre line and a decrease in

the odds of an outcome to the left of the centre line.

The aim here was to define analyses that were comprehensive and

mutually exclusive so that all eligible study results could be be

slotted into one stratum only. Comparisons were specified so that

any trials falling within each stratum could sensibly be pooled for

meta-analysis. Stratification allowed for consideration of effects

within each stratum as well as, or instead of, an overall estimate

for the comparison.

Subgroup analysis and investigation of heterogeneity

Subgroup analysis was performed on the following.

• Trials that reported antioxidants (individual and combined)

given to men with documented elevated levels of sperm DNA

damage, as defined by the trials, who were undergoing fertility

treatment (ART). A minimum of 80% of participants in the

trials had to satisfy this criterion for inclusion. If individual data

were available these were used in preference.

• Trials that reported antioxidants (individual and combined)

given to men with impaired semen parameters who were

undergoing fertility treatment (ART). A minimum of 80% of

participants in the trials had to satisfy this criterion for inclusion.

If individual data were available these were used in preference.

• Treatment was divided into the subgroups of individual and

combined antioxidants for live birth and pregnancy outcomes.

• Subgroup analysis was also performed on those studies that

reported live birth and pregnancy in order to assess any

overestimation of effect and reporting bias.

• Subgroup analysis was also used in the sperm outcomes of

motility and concentration over time, at: three, six and nine

months.

Sensitivity analysis

We performed sensitivity analysis (using the random-effects model

in RevMan software) for the primary outcomes to assess whether

the findings from the analysis were robust. Sensitivity analysis

considered whether conclusions were any different if eligibility was

restricted to studies without high risk of bias.

We also stated that sensitivity analysis would be performed on un-

published studies. These studies may not have been peer reviewed

and thus could be of lower quality. However there were no un-

published trials in this review.

Initially trials were subgrouped according to placebo or no treat-

ment, however after statistical advice all the trials comparing an-

tioxidants to placebo and no treatment were grouped as one then

a sensitivity analysis was performed to assess any evidence of dif-

ference in effect between the placebo and the no-treatment group.

These results are described in the ’Risk of bias in included studies’

section of the review.

R E S U L T S



Description of studies

See: Characteristics of included studies; Characteristics of

excluded studies; Characteristics of studies awaiting classification;

Characteristics of ongoing studies.

Results of the search

Two review authors (MS and RH) scanned the abstracts and titles

of the results of the search strings. The MEDLINE search pro-

duced 406 abstracts; there were six abstracts from CENTRAL,

three from CINAHL, 62 from EMBASE, 107 from the MSDG

database and three from PsycINFO. Two conference abstracts

were found from handsearching the conference proceedings of

the European Society for Human Reproduction and Embryology

(ESHRE) and the American Society for Reproductive Medicine

(ASRM). One title was found from reference lists in reviews.

Five non-English trials were assessed for inclusion: two Chinese,

one Bulgarian, one Japanese and one Iranian. The two Chinese

trials (Li 2005a; Li 2005 ), the Japanese trial (Akiyama 1999) and

the Iranian trial (Peivandi 2010) were included in the analysis.

The Bulgarian study (Nikolova 2007) was excluded as it did not

have random allocation (see Characteristics of excluded studies).

After removal of inappropriate and duplicate studies 53 trials re-

mained: 34 trials were included, 15 were excluded and four trials

were ongoing.

Included studies

There were 34 included trials in this review. Full details of these

trials can be seen in the table of included studies (Characteristics of

included studies). The trials came from 19 different countries and

randomised 2876 couples. Eight trials were based in Italy (Balercia

2005; Balercia 2009; Biagiotti 2003; Cavallini 2004; Galatioto

2008; Lenzi 2003; Lenzi 2004; Lombardo 2002). Three trials were

from Iran (Safarinejad 2009; Safarinejad 2009a; Peivandi 2010).

Two trials each were from USA (Dawson 1990; Sigman 2006),

Tunisia (Keskes-Ammar 2003; Nozha 2001), United Kingdom

(Kessopoulou 1995; Scott 1998), Hungary (Micic 1988; Zavaczki

2003), Kuwait (Omu 1998; Omu 2008) and China (Li 2005; Li

2005a). The remaining trials were from single countries: Japan

(Akiyama 1999), Turkey (Ciftci 2009), Canada (Conquer 2000),

France (Greco 2005), Mexico (Merino 1997), Germany (Rolf

1999), Saudi Arabia (Suleiman 1996), Australia (Tremellen 2007),

Hong Kong (Wang 1983), Netherlands (Wong 2002) and Belgium

(Zalata 1998).

Data were able to be extracted from 28 of these included trials.

The six remaining trials either did not report any data or the

continuous data were reported in medians or ranges (Biagiotti

2003; Lombardo 2002; Merino 1997; Nozha 2001; Wong 2002;

Zalata 1998), see Characteristics of included studies and the anal-

yses (Analysis 1.14; Analysis 1.15; Analysis 1.16; Analysis 1.17;

Analysis 3.9; Analysis 3.10). Attempts were made to contact all

authors of the included trials for further details and clarification.

The duration of treatment period ranged from three weeks with

three weeks follow up (Dawson 1990) to 26 weeks treatment and a

24-month follow up (Wong 2002). The longest follow-up period

was in the trial by Kessopoulou (Kessopoulou 1995), with a three-

week treatment period and a two-year follow-up period.

Three trials (Kessopoulou 1995; Sigman 2006; Tremellen 2007)

enrolled men who, as a couple, were undergoing IVF or ICSI.

There were no trials that enrolled men who were part of a couple

undergoing intrauterine insemination (IUI).

Participants

Most trials included couples who had attended a fertility clinic,

with a fertile partner and had been trying to conceive with regular

intercourse for over one year.

The mean age of the participants ranged from 20 to 52 years. Most

men in the included trials had a deficient level of spermatozoa

in the seminal fluid (oligospermia) or a low motility of sperm

in the seminal fluid (asthenospermia). Trials excluded men with

any inflammatory disease, antibody problems or chromosomal

problems and most trials stated that they did not enrol men who

smoked, took any additional medication or drank alcohol.

Details of inclusion and exclusion criteria are found in

Characteristics of included studies.

Interventions

A wide variety of antioxidants were used in the included trials. The

three comparisons were: antioxidants versus placebo, antioxidants

versus no treatment and antioxidants versus antioxidants (or head

to head).

The comparison ’antioxidants versus placebo’ included the antiox-

idants: vitamin E, combined antioxidants plus minerals, L-acetyl-

carnitine, L-carnitine, L-acetyl carnitine plus L-carnitine, pentox-

ifylline and magnesium.

The comparison ’antioxidants versus no treatment’ included: zinc,

combined antioxidants plus minerals, pentoxifylline, zinc plus vi-

tamin E, zinc plus vitamin E plus vitamin C.

In the analysis placebo and no treatment groups were grouped as

one and the comparison labelled ’antioxidants versus control’.

The third comparison, head to head, was implemented in an at-

tempt to assess whether one antioxidant may be more effective

than another, as stated in the protocol. However in some cases they

may have countered each other as the treatment was also included

in the control (Balercia 2005; Omu 2008; Safarinejad 2009; Scott

1998). The antioxidants used were: L-acetyl carnitine, L-carni-

tine, L-acetyl carnitine plus L-carnitine, ethyl cysteine, vitamin E,

docosahexaenoic acid, vitamin C, selenium, vitamin B, combined

antioxidants plus minerals and N-acetyl cysteine.

Outcomes

The primary outcome for this review was as follows.



• Live birth per couple. Three trials reported live birth

(Kessopoulou 1995; Omu 1998; Suleiman 1996) in the

antioxidant versus control groups.

Secondary outcomes for this review were as follows.

• Pregnancy rate per couple, as reported by 16 trials (Balercia

2005; Balercia 2009; Cavallini 2004; Galatioto 2008; Lenzi

2003; Lenzi 2004; Li 2005; Omu 1998; Peivandi 2010; Rolf

1999; Safarinejad 2009a; Sigman 2006; Suleiman 1996;

Tremellen 2007; Wang 1983; Zavaczki 2003). Li 2005 (Li 2005)

used head to head comparisons. Balercia 2005 (Balercia 2005)

was multi-armed and used both head to head and a control while

the remaining trials investigated antioxidant versus control.

• Miscarriage rate, as reported by three trials (Omu 1998;

Suleiman 1996; Tremellen 2007) in the antioxidant versus

control comparison.

• DNA fragmentation, as reported by one trial (Greco 2005).

This trial compared antioxidant versus control.

The sperm motility and concentration outcomes were divided into

three groups: measurement at three, six and nine months or more;

the included trials measured motility and concentration at these

different points in time. This analysis was only useful in directly

comparing the same trials reporting at the three time points and

not in comparing results of meta analyses that included different

subsets of trials.

• Sperm motility at three months or less was reported by 13

trials (Akiyama 1999; Ciftci 2009; Conquer 2000; Dawson

1990; Greco 2005; Keskes-Ammar 2003; Li 2005; Micic 1988;

Omu 2008; Peivandi 2010; Scott 1998; Sigman 2006; Zavaczki

2003).

• Sperm motility at six months was measured by four trials

(Balercia 2005; Balercia 2009; Safarinejad 2009; Suleiman

1996).

• Sperm motility at nine months or more was reported by

three trials (Balercia 2005; Balercia 2009; Safarinejad 2009a).

• Sperm concentration at three months or less was reported

by nine trials in total (Akiyama 1999; Conquer 2000; Ciftci

2009; Greco 2005; Peivandi 2010; Rolf 1999; Wang 1983;

Zavaczki 2003).

• Sperm concentration at six months was reported as an

outcome by a total of five trials (Balercia 2005; Balercia 2009;

Lenzi 2004; Li 2005a; Safarinejad 2009; Wang 1983).

• Sperm concentration at nine months or more was reported

on by three trials (Balercia 2005; Balercia 2009; Safarinejad

2009a).

• Side effects were subgrouped according to the type of side

effect, as described by the trials. There were only seven trials that

reported side effects. Failure by the remaining included studies to

report adverse effects could be construed as selective reporting.

The side effects reported were mainly gastrointestinal upsets

(Cavallini 2004; Kessopoulou 1995; Safarinejad 2009a; Sigman

2006; Tremellen 2007; Zavaczki 2003). These were reported as

mild epigastria, nausea, gastric acidity, gastro-oesophageal reflux,

constipation and diarrhoea. One of the six trials (Cavallini 2004)

also reported on the side effect of euphoria. The trial by Li (Li

2005) reported that no side effects were found in either the

treatment or control groups. It should also be noted that the trial

by Cavallini (Cavallini 2004) had unexplained differences in

randomisation and analysis numbers for this outcome, and

therefore introduced some reporting bias.

Excluded studies

In total 15 trials were excluded. Six trials (Cavallini 2004a; Ebisch

2006; Pryor 2003; Rolf 1998; Tremellen 2006; Zalata 1998a) were

excluded as they reported the initial analysis or were a conference

proceeding of a later, included trial. Five trials (Comhaire 2005;

Micic 2001; Nikolova 2007; Pawlowicz 2001; Stanislavov 2009)

were excluded because they did not use a randomised sequence to

allocate the participants to the treatment and control groups. Four

trials (Ebisch 2003; Elgindy 2008; Vicari 2001; Vicari 2001a) did

not have appropriate inclusion criteria for population, outcomes

or controls. Refer to the table Characteristics of excluded studies.

Studies awaiting classification

There is one trial (Wang 2010) awaiting classification. It has not

yet been assessed.

Ongoing studies

Four trials were ongoing (Revel 2006; Sadeghi 2008; Tsafrir 2010;

Gonzalez 2009).

Risk of bias in included studies

Adequate sequence generation

All included trials were randomised. Four trials (Akiyama 1999;

Kessopoulou 1995; Lenzi 2003; Peivandi 2010) had a randomised

crossover design. In the meta-analysis only the first phase data were

used as all trials reported first and second phase data separately.

Including crossover data may introduce reporting bias due to the

fact that it is unusual for a trial to report usable data at each phase.

The remaining 30 trials had a randomised parallel group de-

sign. Only 10 trials described their methods of randomisation

(Biagiotti 2003; Galatioto 2008; Keskes-Ammar 2003; Rolf 1999;

Safarinejad 2009; Safarinejad 2009a; Scott 1998; Sigman 2006;

Tremellen 2007; Wong 2002). The predominant method was by

computer generated blocks. Some degree of selection bias may



have been present in the trials due to the high numbers of included

trials that did not describe their method of randomisation (24 out

of 34 trials).

One study (Li 2005) had a large imbalance between the interven-

tion and control groups at the randomisation stage; 150 men were

randomised: 90 into the treatment group and 60 into the control

group. This imbalance was not explained in the report. Attempts

were made to contact the author but as yet there has been no reply.

Allocation

The methods of allocation concealment were generally quite

poorly described in the included studies. Therefore there was

some risk of selection bias in the trials under review. Nine tri-

als (Cavallini 2004; Ciftci 2009; Galatioto 2008; Rolf 1999;

Safarinejad 2009; Sigman 2006; Tremellen 2007; Wong 2002;

Peivandi 2010) described their method of allocation. These meth-

ods included anonymous coloured boxes, sealed opaque envelopes

and numbered bottles.

Blinding

Seventeen trials (Balercia 2005; Balercia 2009; Cavallini 2004;

Kessopoulou 1995; Lenzi 2003; Lenzi 2004; Li 2005; Lombardo

2002; Peivandi 2010; Rolf 1999; Safarinejad 2009; Safarinejad

2009a; Scott 1998; Sigman 2006; Suleiman 1996; Tremellen

2007; Wong 2002) were described as randomised, double blind

controlled trials. The researchers and patients were blinded. Two

trials (Ciftci 2009; Dawson 1990) stated that a placebo was used

as the control but only the patients were blinded. Other trials

(Conquer 2000; Greco 2005; Merino 1997; Wang 1983; Zavaczki

2003) used a placebo as the control but did not discuss blinding.

One trial (Galatioto 2008) was open label but stated that the

pharmacy was blinded during the randomisation process. One trial

(Keskes-Ammar 2003) was described as open label however the

numeric code was withheld from the investigators and patients.

Suleiman 1996 reported that if a couple became pregnant then

the treatment was stopped; however they did not appear to stop

the placebo. This suggests that the investigators had knowledge of

whether the patients were in the placebo or antioxidant.

Incomplete outcome data

Only two trials (Balercia 2009; Galatioto 2008) actually stated

that they used intention to treat in their analysis, however most

of the included trials accounted for the participants that withdrew

from their trials and then analysed the groups in an intention-to-

treat fashion.

Four trials had over 20% withdrawal from their trials. One trial (

Keskes-Ammar 2003) had over 50% drop out rate; these men were

accounted for and the main reason given was non-compliance.

Cavallini 2004 had 30% dropout rate and reasons were provided

for 53 out of the 55 drop outs; these reasons included refusal

due to the chance of taking a placebo and preference for assisted

reproduction techniques. There also remained some confusion in

this trial on the total numbers randomised and analysed. Li 2005a

and Suleiman 1996 had slightly over 20% withdrawal from their

trials.

One trial (Suleiman 1996) had a large imbalance in numbers.

There were found to be 52 in the treatment group and 35 in the

placebo once the code had been broken at the end of the trial.

There was no indication of how the randomisation was performed

therefore the trial did not perform intention to treat. The dropouts

were however accounted for: many couples had left the region and

some simply failed to continue.

Selective reporting

There was great potential for reporting bias throughout this review

as no outcome had been consistently reported by all studies and

the key outcomes were reported by a minority of studies.

The trial by Cavallini (Cavallini 2004) had unexplained differences

in randomisation and analysis numbers and therefore may have

introduced some reporting bias.

Four trials (Balercia 2005; Balercia 2009; Scott 1998; Sigman

2006) gave pregnancy data although pregnancy as an outcome was

not stated a priori in the protocols. Li 2005a stated that pregnancy

was an outcome but did not provide the data. One trial (Wang

1983) gave follow-up data on the treatment group but no data

were supplied on the control group.

Three trials reported on the adverse event of miscarriage (

Tremellen 2007; Suleiman 1996; Omu 1998).

Six trials reported on side effects, which were mainly gas-

trointestinal (Cavallini 2004; Kessopoulou 1995; Safarinejad

2009a; Sigman 2006; Tremellen 2007; Zavaczki 2003). Cavallini

(Cavallini 2004) also reported euphoria as a side effect. The ma-

jority of included trials did not report side effects and this could

be construed as a reporting bias.

Other potential sources of bias

Funding sources were stated by nine trials (Conquer 2000;

Kessopoulou 1995; Lenzi 2003; Lombardo 2002; Omu 1998;

Peivandi 2010; Rolf 1999; Wang 1983; Zavaczki 2003). Two trials

(Conquer 2000; Wang 1983) stated that funding was from a com-

mercial source and the remaining seven obtained funding through

non-commercial avenues or university grants. However three of

these non-commercially funded trials (Kessopoulou 1995; Lenzi

2003; Zavaczki 2003) received the medication from commercial

interests.

Publication bias was assessed using a funnel plot (Figure 1). Preg-

nancy outcome was used for the funnel plot as there were only two

studies in the primary outcome of live birth. The plot appeared

to be symmetrical and therefore we assumed that there was little

publication bias.



Figure 1. Funnel plot of comparison: 1 Antioxidant(s) versus placebo, outcome: 1.2 Pregnancy rate per

couple randomised.

Trials comparing an antioxidant to a placebo or to no treatment

were grouped together and compared in the subgroups. Sensitivity

analysis was performed on the outcomes whereby the placebo data

were removed in order to assess whether the ’no treatment’ trials

were biasing the results. This was only possible for the outcome of

sperm motility at three months and the result remained statistically

significant. The other outcomes either contained only placebo

trials or contained only one no-treatment trial, therefore sensitivity

analysis could not be performed.

Effects of interventions

See: Summary of findings for the main comparison

Antioxidant/s versus control for male subfertility

Antioxidant(s) versus control

Live birth per couple randomised

Overall there was a statistically significant difference in favour of

the antioxidant treated group compared with the control group

for live birth (pooled OR 4.85, 95% CI 1.92 to 12.24; P = 0.0008,

I2 = 0%) (Analysis 1.1). Three trials reported on this outcome

(Kessopoulou 1995; Omu 1998; Suleiman 1996). In total there

were 20 live births from a total of 214 couples randomised, 18

(15%) in the antioxidant group (n = 116) and two (2%) in the

control group (n = 98) (Figure 2). The I2 statistic in the analysis

was 0% however sensitivity analysis was performed on the trial by

Suleiman 1996 as this trial had more than 20% of participants

drop out of the trial. There remained a statistically significant

difference in favour of the antioxidant-treated group compared

with the control group for live birth (pooled OR 3.94, 95% CI

1.14 to 13.55; P = 0.03, I2 = 0%).



Figure 2. Forest plot of comparison: 1 Antioxidant(s) versus placebo, outcome: 1.1 Live birth per couple

randomised.

Two trials (Kessopoulou 1995; Suleiman 1996) reported on this

outcome comparing the intervention of vitamin E versus placebo.

Kessopoulou 1995 included couples undergoing IVF or ICSI.

There was a statistically significant difference (pooled OR 6.44,

95% CI 1.72 to 24.04; P = 0.006, I2 = 0%) in the number of live

births between the antioxidant and placebo groups that favoured

the antioxidant over the placebo.

One trial (Omu 1998) reported on live births per couple ran-

domised and compared zinc versus no treatment. In total there

were 10 live births from 97 couples randomised, eight in the an-

tioxidant group (n = 49) and two in the no treatment group (n =

48). There was a statistically significant difference (OR 3.67, 95%

CI 1.00 to 13.51; P = 0.05) in the number of live births between

the antioxidant and no treatment, in favour of the antioxidant.

Pregnancy rate per couple randomised

Fifteen trials reported the outcome of pregnancy rate per cou-

ple randomised (Balercia 2005; Balercia 2009; Cavallini 2004;

Galatioto 2008; Lenzi 2003; Lenzi 2004; Omu 1998; Peivandi

2010; Rolf 1999; Sigman 2006; Safarinejad 2009a; Suleiman

1996; Tremellen 2007; Wang 1983; Zavaczki 2003). There were

964 couples in total, 515 in the antioxidant group and 449 in the

control group. In total there were 96 pregnancies, 82 (16%) in the

antioxidant group and 14 (3%) in the control group.


95% CI 2.65 to 6.59; P < 0.00001, I2 = 0%) (Analysis 1.2) in

the number of pregnancies between the antioxidant and control

groups in favour of the antioxidant group over the control group

(Figure 3).



Figure 3. Forest plot of comparison: 1 Antioxidant(s) versus placebo, outcome: 1.2 Pregnancy rate per

couple randomised.



The trial by Cavallini 2004 included men with variocoele associ-

ated oligoasthenospermia whereas many of the other included tri-

als excluded men with variocoele (see Characteristics of included

studies). Heterogeneity was however low in this analysis and there-

fore sensitivity analysis was not performed.

Sensitivity analysis was performed on those trials (Cavallini 2004;

Suleiman 1996; Wang 1983) that reported over 20% dropouts.


95% CI 2.08 to 5.95; P < 0.00001, I2 = 0%) in favour of the

antioxidant group over the control group.

Two of the 15 trials included couples undergoing IVF or ICSI.

When these two trials (Sigman 2006; Tremellen 2007) were re-

moved the effect of antioxidants over control remained as a statis-

tically significant difference for the remaining trials (pooled OR

4.52, 95% CI 2.71 to 7.53; P < 0.00001, I2 = 0%), in favour

of the antioxidant over control. When these two trials (Tremellen

2007; Sigman 2006) were subgrouped together there was also a

statistically significant difference in favour of the antioxidant over

the control (pooled OR 3.06, 95% CI 1.10 to 8.47; P = 0.03, I2

= 7%).

After removing those trials that used a placebo as a control, as

opposed to no treatment, there remained a statistically significant

difference (pooled OR 4.97, 95% CI 1.63 to 15.14; P = 0.005, I2 = 0%) although the confidence intervals widened, in favour of

the antioxidant group over the no-treatment group.

Two trials (Rolf 1999; Wang 1983) were not estimable due to no

pregnancies in either the treatment or control group.

Two trials (Galatioto 2008; Omu 1998) reported on pregnancy

rate per couple randomised, comparing antioxidants versus no

treatment. In total there were 14 pregnancies from 130 couples

randomised, 12 in the treatment group (n = 69) and two in the

no-treatment group (n = 70). There was a statistically significant

difference (pooled OR 4.97, 95% CI 1.63 to 15.14; P = 0.005)

in the number of pregnancies between the antioxidant group and

the no-treatment group, in favour of the antioxidant group. No

heterogeneity was seen in this analysis (Chi2 = 0.07, I2 = 0%).

Two further comparisons were created to assess any overestimate of

benefit or reporting bias that may exist in the pregnancy analysis.

• Live birth versus pregnancy: two (Omu 1998; Suleiman

1996) out of three trials that reported on live birth and also

reported on pregnancy rate were analysed (see Figure 4). The live

birth analysis showed a statistically significant difference in

favour of the antioxidants (pooled OR 4.73, 95% CI 1.82 to

12.27; P = 0.001, I2 = 0%). This analysis had slightly lower

evidence of effect than when these same trials were analysed in

terms of the pregnancy outcome (pooled OR 5.53, 95% CI 2.34

to 13.08; P < 0.0001, I2 = 0%) (see Analysis 2.1). The results for

the two analyses appear similar therefore there is no clear

evidence of overestimation of benefit in the the full (all studies)

pregnancy analysis. If the results for pregnancy suggested a larger

effect than the corresponding result for live birth then we would

have assumed that the full pregnancy analysis overestimated the

benefit of antioxidants. In the trials that reported on both live

birth and pregnancy 22% of the treatment group became

pregnant and 17% had a live birth, while 2% of the control

became pregnant and 2% had a live birth.

Figure 4. Forest plot of comparison: 2 Live birth versus pregnancy, outcome: 2.1 Live birth.



• Pregnancy: the trials (Omu 1998; Suleiman 1996) that

reported on both live birth and pregnancy (pooled OR 5.53,

95% CI 2.34 to 13.08; P < 0.0001, I2 = 0%) (Analysis 1.18;

Figure 5) were compared to all other trials reporting pregnancy

(Balercia 2005; Galatioto 2008; Lenzi 2003; Lenzi 2004;

Peivandi 2010; Rolf 1999; Safarinejad 2009a; Sigman 2006;

Tremellen 2007; Wang 1983; Zavaczki 2003) (pooled OR 4.40,

95% CI 2.78 to 6.97; P < 0.00001, I2 = 0%). The results for the

two analyses appear similar thus giving us some confidence that

the reporting bias in this outcome was low. In the trials that

reported both live birth and pregnancy 22% became pregnant in

the antioxidant group and 2% in the control, while in the

pregnancy-only reported trials 15% of the antioxidant group

became pregnant while 3% became pregnant in the control group

Figure 5. Forest plot of comparison: 1 Antioxidant(s) versus control, outcome: 1.16 Live birth and

pregnancy.



Two trials (Galatioto 2008; Tremellen 2007) compared combined

antioxidants. There were 25 pregnancies in total, 21 in the antiox-

idant group (n = 58) and 4 in the control (n = 42). There was a

statistically significant difference in pregnancy rates (pooled OR

3.97, 95% CI 1.39 to 11.33; P = 0.01, I2 = 0%) in favour of the

combined antioxidants over the control.

One trial (Balercia 2005) compared L-acetyl carnitine to placebo.

There were three pregnancies in total, two in the antioxidant group

(n = 15) and one in the placebo group (n = 5). The placebo group

was divided by three as this trial had multiple arms and the placebo

data appeared three times in the analysis. The analysis showed no

statistically significant difference (OR 0.61, 95% CI 0.04 to 9.64;

P = 0.72) in pregnancy rates between the antioxidant and placebo

groups.

Three trials (Balercia 2005; Lenzi 2003; Peivandi 2010) compared

L-carnitine to control. There were 12 pregnancies in total, 11 in

the antioxidant group (n = 73) and 1 in the control group (n =

63). There was a statistically significant difference in pregnancy

rates (pooled OR 5.08, 95% CI 1.51 to 17.09; P = 0.009, I2 =

29%) in favour of the antioxidant group over the control group.

Four trials (Balercia 2005; Cavallini 2004; Lenzi 2004; Sigman

2006) assessed L-acetyl carnitine + L-carnitine versus placebo.

There were 21 pregnancies in total, 19 (n = 96) in the antioxi-

dant group and 3 in the placebo (n = 87). There was a statistically

significant difference significance in pregnancy rates (pooled OR

4.48, 95% CI 1.77 to 11.36; P = 0.002, I2 = 0%) in favour of the

antioxidant group over the placebo group.

Two trials (Balercia 2009; Safarinejad 2009a) reported on coen-

zyme versus placebo. There were nine pregnancies in total (n =

272). All pregnancies occurred in the Balercia 2009 trial and none

in the Safarinejad 2009a trial. Balercia 2009 was the only trial to

be considered for this outcome as there were no pregnancies in

the second trial. Balercia 2009 showed no statistically significant

difference (pooled OR 2.16, 95% CI 0.53 to 8.82; P = 0.28) in

pregnancy rates between the antioxidant and placebo groups.

Only one trial (Wang 1983) reported on pentoxifylline versus

placebo and there were no pregnancies in either group, therefore

the results were not estimable.

One trial (Zavaczki 2003) reported on magnesium versus placebo.

There was one pregnancy in the antioxidant group (n = 10) and

none in the placebo (n = 10). The results showed no statistically

significant difference in pregnancy rates between the antioxidant

group and the placebo group (OR 7.39, 95% CI 0.15 to 372.38;

P = 0.32).

One trial (Suleiman 1996) reported on vitamin E versus placebo.

There were 11 pregnancies in the antioxidant group (n = 52)

and none in the placebo group (n = 35). There was a statistically

significant difference (OR 6.64, 95% CI 1.84 to 23.93; P = 0.004)

in the pregnancy rate in favour of the antioxidant group over the

placebo group. However this trial had a large degree of attrition

due to drop outs leading to an imbalance between the groups; the

confidence intervals were quite large.

One trial (Rolf 1999) reported on vitamin C + vitamin E versus

placebo. There were no pregnancies in either group therefore the

results were not estimable.

One trial (Omu 1998) reported on pregnancy rate with the com-

parison of zinc versus no treatment. A statistically significant dif-

ference was seen (OR 4.75, 95% CI 1.49 to 15.20; P = 0.009) in

favour of the antioxidant group over the no-treatment group.

Adverse event: miscarriage rate per couple randomised

Three trials (Omu 1998; Suleiman 1996; Tremellen 2007) re-

ported on miscarriage per couple randomised. In total there were

five miscarriages in the antioxidant group (n = 139) and two in

the control group (n = 103). There was no statistically significant

difference (pooled OR 1.54, 95% CI 0.32 to 7.30; P = 0.59, I2

= 20%) (Analysis 1.3) in miscarriage rate per couple randomised

between the antioxidant and placebo groups. The confidence in-

tervals of the three trials overlapped the line of no effect (Figure

6).



Figure 6. Forest plot of comparison: 1 Antioxidant(s) versus placebo, outcome: 1.3 Adverse event:

miscarriage rate per couple randomised.

Stillbirth rate per couple randomised

There were no trials of antioxidants versus control that reported

on stillbirths per couple randomised.

Level of sperm DNA fragmentation

There was only one trial (Greco 2005) that reported on the out-

come of sperm fragmentation levels. There was a statistically sig-

nificant difference (MD -13.80, 95% CI -17.50 to -10.10; P ≤

0.00001) (Analysis 1.4) in favour of the antioxidant group (vita-

min C + vitamin E) over the placebo group (Figure 7).

Figure 7. Forest plot of comparison: 1 Antioxidant(s) versus placebo, outcome: 1.10 DNA fragmentation.



Total sperm motility at three months or less

Ten trials (Ciftci 2009; Conquer 2000; Dawson 1990; Greco

2005; Micic 1988; Omu 2008; Peivandi 2010; Scott 1998; Sigman

2006; Zavaczki 2003) reported on total sperm motility at three

months or less. In total there were 514 participants, 302 in the an-

tioxidant group and 212 in the control group. There was a statis-

tically significant difference (MD 31.26, 95% CI 31.17 to 31.35;

P < 0.00001, I2 = 96%) (Analysis 1.5) in favour of the antioxidant

group over the control group (Figure 8). The heterogeneity with

the I2 statistic at 96% was very high. Sensitivity analysis was per-

formed on the trial of Peivandi 2010 as the data in this trial were

outlying. The standard deviations had unusually low values when

compared to other trials. The trial by Peivandi also carried 99.8%

of the weight in the analysis. A random-effects model was used

and after sensitivity analysis the statistically significant difference

remained, in favour of the antioxidant group over the control (MD

11.72, 95%CI 6.94 to 16.49; P < 0.00001) and the I2 dropped

to 56%. As heterogeneity remained high we were unable to pool

these data and only subtotals were used in the analysis.



Figure 8. Forest plot of comparison: 1 Antioxidant(s) versus placebo, outcome: 1.5 Sperm total motility at

3 months or less.



Total sperm motility at six months

Seven trials (Balercia 2005; Balercia 2009; Lenzi 2004; Safarinejad

2009; Safarinejad 2009a; Sigman 2006; Suleiman 1996) reported

on total sperm motility at six months. In total there were 963

participants, 625 in the antioxidant group and 338 in the con-

trol group. This difference in numbers between the treatment and

control groups was due to the splitting of the control arm of the

three or four-arm trials. There was a statistically significant differ-

ence (MD 4.19, 95% CI 3.81 to 4.56; P < 0.00001) (Analysis 1.6)

in favour of the antioxidant group over the control group (Figure

9). Substantial heterogeneity was found in this analysis (Chi2 =

90.87, I2 = 89%). As heterogeneity was large, a sensitivity anal-

ysis was performed by removing the study with over 20% drop

out (Suleiman 1996) but there was little change to the I2 statis-

tic. Therefore, due to unexplained heterogeneity, the totals were

removed in this analysis and only subtotals used.




6 months.



Only one comparison (Balercia 2005; Lenzi 2004; Sigman 2006),

L-carnitine + L-acetyl carnitine versus placebo at six months, had

confidence intervals that crossed the line of no effect. One com-

parison, (Balercia 2009; Safarinejad 2009a) coenzyme Q10 versus

placebo at six months, carried 42.9% of the weight of this analysis

and was in favour of the antioxidant group over the placebo group

(MD 4.50, 95% CI 3.93 to 5.07; P < 0.00001, I2 = 0%).

Three trials (Balercia 2005; Lenzi 2004; Sigman 2006) reported

on total sperm motility with the comparison of L-carnitine + L-

acetyl carnitine versus placebo at six months. In total there were

97 participants, 57 in the antioxidant group and 40 in the placebo

group. There was a statistically significant difference in the total

sperm motility in favour of the antioxidant over the placebo group

(MD 5.48, 95% CI 0.44 to 10.52; P = 0.03). Substantial hetero-

geneity was found in this analysis (Chi2 = 8.61, I2 = 77%).

Total sperm motility at nine months or more

Three trials (Balercia 2005; Balercia 2009; Safarinejad 2009a) re-

ported on total sperm motility at nine months or more. In total

there were 332 participants, 181 in the antioxidant and 151 in

the placebo group. There was a statistically significant difference

in treatment effect in favour of the antioxidant over the control

group (MD 1.38, 95% CI 0.81 to 1.95; P < 0.00001) (Analysis

1.7; Figure 10). Heterogeneity was found in this analysis (Chi2

= 10.98, I2 = 64%). Three comparisons had confidence intervals

that crossed the line of no effect. One comparison, coenzyme Q10

(Balercia 2005; Safarinejad 2009a) versus control at 56 weeks, car-

ried 98.9% of the weight of this analysis and was in favour of

the antioxidant group over the control group (MD 1.31, 95% CI

0.74 to 1.88; P < 0.00001). Heterogeneity was moderate in the

analysis, probably due to the variation of antioxidants, therefore

a random-effects model was used. Only subtotals were able to be

used in the analysis.


9 months or more.



Sperm concentration at three months or less

Seven trials ( Ciftci 2009; Conquer 2000; Greco 2005; Peivandi

2010; Rolf 1999; Wang 1983; Zavaczki 2003) reported on sperm

concentration at three months or less. In total there were 320

participants, 162 in the antioxidant and 158 in the placebo group.

There was no statistically significant difference (MD 6.04, 95% CI

-5.42 to 17.50; P = 0.30) (Analysis 1.8) between the antioxidant

and the placebo groups (Figure 11). Heterogeneity was high (I2

= 93%) in this analysis. A random-effects model was used and a

sensitivity analysis performed for the trial Peivandi 2010. This trial

had outlying data as the standard deviations were much lower than

for the other studies. When this trial was removed from analysis

the I2 statistic became 0% and there was no statistically significant

difference between the groups (MD 2.64, 95% CI -0.52 to 5.81;

P = 0.10, I2 = 0%).

Figure 11. Forest plot of comparison: 1 Antioxidant(s) versus placebo, outcome: 1.8 Sperm concentration

at 3 months or less.



Two trials (Greco 2005; Rolf 1999) reported on sperm concentra-

tion with the comparison of vitamin C + vitamin E versus placebo

at two months. In total there were 95 participants, 47 in the an-

tioxidant group and 48 in the placebo group. A statistically signif-

icant difference between the antioxidant and placebo group could

not be found (MD 1.36, 95% CI -10.01 to 12.72; P = 0.82).

Moderate heterogeneity was found in this analysis (Chi2 = 2.07, I2 = 52%).

Sperm concentration at six months

Six trials (Balercia 2005; Balercia 2009; Lenzi 2004; Safarinejad

2009; Safarinejad 2009a; Wang 1983) reported on sperm con-

centration at six months in eight different comparisons. In total

there were 825 participants, 536 in the antioxidant and 289 in

the placebo group. There was a statistically significant difference

in treatment effect in favour of the antioxidant over the placebo

group (MD 5.25, 95% CI 4.43 to 6.08; P < 0.00001) (Analysis

1.9; Figure 12). Heterogeneity was moderate in this analysis (Chi2= 19.05, I2= 53%). The raised heterogeneity was probably due

to the variation in antioxidants. Five comparisons had confidence

intervals that crossed the line of no effect. Due to the heterogene-

ity a random-effects model was applied and subtotals were used in

the analysis.




at 6 months.



Two trials (Balercia 2005; Lenzi 2004) reported on sperm concen-

tration with the comparison L-carnitine + L-acetyl carnitine versus

placebo at six months. In total there were 76 participants, 45 in

the antioxidant group and 31 in the placebo group. A statistically

significant difference between the antioxidant and placebo group

could not be found (MD 0.63, 95% CI -5.93 to 7.18; P = 0.85).

There was no heterogeneity in this analysis (Chi2 = 0.19, I2 = 0%).

Two trials (Balercia 2009, Safarinejad 2009a) reported on sperm

concentration with the comparison of coenzyme Q10 versus

placebo at six months. In total there were 272 participants, 136 in

the antioxidant group and 136 in the placebo group. There was


the placebo (MD 5.50, 95% CI 4.34 to 6.67; P < 0.00001). Het-

erogeneity was moderate (Chi2 = 1.92, I2 = 48%) in this analysis.

Sperm concentration at nine months or more

Three trials (Balercia 2005; Balercia 2009; Safarinejad 2009a) re-

ported on sperm concentration at nine months or more in five

different comparisons. In total there were 332 participants, 181 in

the antioxidant group and 151 in the placebo group. There was a


the placebo (MD 1.61, 95% CI 0.61 to 2.61; P = 0.002) (Analysis

1.10), see Figure 13. Heterogeneity could not be found in this

analysis (Chi2 = 3.79, I2 = 0%). One trial (Safarinejad 2009a) car-

ried 96.1% of the weight of this pooled analysis as it had a larger

sample size and tighter confidence intervals.


at 9 months or more.

Two trials (Balercia 2009; Safarinejad 2009a) reported on sperm

concentration with the comparison coenzyme Q10 versus placebo

at nine months or more. A statistically significant difference was

seen in favour of the the antioxidant over the placebo group (MD

1.53, 95% CI 0.51 to 2.55; P = 0.003). One trial (Safarinejad

2009a) carried 96.1% of the weight of this analysis.



Total sperm motility and sperm concentration over time

Trials were also subgrouped according to sperm motility over time.

A random-effects model was used due to high heterogeneity in the

following analyses.

• At three months or less (MD 31.26, 95% CI 31.17 to

31.36; P < 0.00001) (Analysis 1.11; Figure 14) a statistically

significant difference in favour of the antioxidant, however the I2

statistic was 97%. When sensitivity analysis was performed for

Peivandi 2009 (Peivandi 2010) due to outlying data the

heterogeneity remained high at 71%.

Figure 14. Forest plot of comparison: 1 Antioxidant(s) versus control, outcome: 1.17 Total sperm motility

over time.



• At six months there was a statistically significant difference

in treatment effect in favour of the antioxidant over the control

group (MD 5.34, 95% CI 4.91 to 5.77; P < 0.00001) and the I2

statistic was 84%. Sensitivity analysis was performed for

Sulieman (Suleiman 1996) due to >20% drop outs however

there was only a slight decrease in heterogeneity.

• At nine months there was also a statistically significant

difference in treatment effect in favour of the antioxidant over

the placebo (MD 1.35, 95% CI 0.78 to 1.92; P<0.00001, I2 =

68%).

Sperm concentration over time:

• at three months or less (MD 12.74, 95% CI 10.23 to

15.26; P < 0.00001) (Analysis 1.12; Figure 15) a statistically

significant difference in favour of the antioxidant over the

control however the I2 statistic was 94%. When sensitivity

analysis was performed for Peivandi 2009 (Peivandi 2010) due to

outlying data the I2 statistic became 0% and the result changed

to become not statistically significant (MD 2.70, 95% CI -0.47

to 5.88; P = 0.10);

Figure 15. Forest plot of comparison: 1 Antioxidant(s) versus control, outcome: 1.18 Sperm concentration

over time.

• at six months (MD 6.32, 95% CI 5.40 to 7.24; P <

0.00001) a statistically significant difference of the antioxidant

over the control however the I2 statistic = 69%;

• at nine months or more (MD 1.56, 95% CI 0.55 to 2.57; P



= 0. 003, I2 = 0%) a statistically significant difference in favour

of the antioxidant over the control.

Side effects

Gastrointestinal side effects

Six trials (Cavallini 2004; Kessopoulou 1995; Safarinejad 2009a;

Sigman 2006; Tremellen 2007; Zavaczki 2003) reported on gas-

trointestinal side effects with the comparison of antioxidants ver-

sus placebo. In total there were 426 participants, 219 in the an-

tioxidant group and 207 in the placebo group. A statistically sig-

nificant difference between the antioxidant and placebo groups

could not be found (pooled OR 1.63, 95% CI 0.48 to 5.58; P =

0.44) (Analysis 1.13; Figure 16). There was no heterogeneity (Chi2 = 2.49, I2 = 0%).

Figure 16. Forest plot of comparison: 1 Antioxidant(s) versus placebo, outcome: 1.11 Side effects.

Euphoria

One trial (Cavallini 2004) reported on euphoria as a side effect

with the comparison of antioxidants versus placebo. A statistically

significant difference between the antioxidant and placebo group

could not be found (OR 1.21, 95% CI 0.16 to 9.01; P = 0.85) (

Analysis 1.13; Figure 16).

Antioxidant(s) versus antioxidant(s) - head to head

The total summary statistic was disabled for this analysis as there

was no reason to pool direct comparisons.

Pregnancy rate per couple randomised

Two trials (Balercia 2005; Li 2005 ) reported on pregnancy rates

with three different comparisons (see Analysis 3.1; Figure 17). All

three comparisons crossed the line of no effect. There were 10

pregnancies form 90 couples (11%) in the L-acetyl carnitine + L-

carnitine group and 2 pregnancies from 60 couples in the control

group (3%). The controls were L-acetyl carnitine, carnitine and

vitamin E + vitamin C.



Figure 17. Forest plot of comparison: 3 Antioxidant(s) versus antioxidant(s), outcome: 3.1 Pregnancy per

couple randomised.

One trial (Balercia 2005) reported on the outcome of pregnancy

rates with the comparison of L-acetyl carnitine + L-carnitine (treat-

ment) versus L-acetyl carnitine (control). There were two preg-

nancies in the L-acetyl carnitine + L carnitine group and two in

the L-acetyl carnitine. .

Balercia (Balercia 2005) also reported on the outcome of preg-

nancy rate with the comparison of L-acetyl carnitine + L-carnitine

versus L-carnitine. There were three pregnancies in the treatment

group and two in the control group.

Sperm total motility at three months or less

Seven trials (Akiyama 1999; Conquer 2000; Dawson 1990;

Keskes-Ammar 2003; Li 2005; Omu 2008; Scott 1998) reported

on sperm motility at three months or less in nine different com-

parisons (Analysis 3.2) and (Figure 18).



Figure 18. Forest plot of comparison: 3 Antioxidant(s) versus antioxidant(s), outcome: 3.2 Sperm total

motility at 3 months or less.



Only one trial (Dawson 1990) showed a statistically significant

difference in measure of effect. This study compared ascorbic acid

(vitamin C) 200 mg/day versus vitamin C 1000 mg/day. There

was a statistically significant difference (MD -43.00, 95% CI -

67.10 to -18.90; P = 0.0005) in favour of the 1000 mg/day in

sperm motility.

Sperm total motility at six months

Two trials (Balercia 2005, Safarinejad 2009) reported on five dif-

ferent comparisons of antioxidants versus antioxidants (Analysis

3.3; Figure 19).


motility at 6 months.

The comparisons of L-acetyl carnitine + L-carnitine versus L-car-

nitine (Balercia 2005) (MD -3.46, 95% CI -11.41 to 4.49; P =

0.39) and L-acetyl carnitine + L-carnitine versus L-acetyl carni-

tine (Balercia 2005) (MD 0.64, 95% CI -7.58 to 8.86; P = 0.88)

showed no statistically significant difference in effect between these

two different antioxidants.

Safarinejad (Safarinejad 2009) also reported on three other com-

parisons.

Selenium versus N-acetyl cysteine, with a statistically significant



difference in favour of selenium (MD 1.30, 95% CI 0.39 to 2.21;

P = 0.005).

Selenium versus selenium + N-acetyl cysteine with a statistically

significant difference in favour of selenium + N-acetyl cysteine over

selenium alone (MD -3.10, 95% CI -4.16 to -2.04; P < 0.00001).

N-acetyl cysteine versus selenium + N-acetyl cysteine with a sta-

tistically significant difference in favour of selenium plus N-acetyl

cysteine (MD -4.40, 95% CI -5.31 to -3.49; P < 0.00001).

Sperm total motility at nine months

Only one trial (Balercia 2005) reported on sperm motility at nine

months using the two comparisons of L-acetyl carnitine + L-car-

nitine versus L-carnitine (MD -5.27, 95% CI -12.61 to 2.07; P =

0.16) and L-acetyl carnitine + L-carnitine versus L-acetyl carnitine

(MD -1.57, 95% CI -7.70 to 4.56; P = 0.62) with no evidence of

effect in either of these comparisons (Analysis 3.4; Figure 20).


motility at 9 months or more.

Sperm concentration at three months

Three trials (Akiyama 1999; Conquer 2000; Li 2005a) reported

on sperm concentration at three months (Analysis 3.5; Figure 21).

The trial by Akiyama showed no statistically significant difference

in effect between the antioxidant ethyl cysteine versus vitamin E

(MD 2.20, 95% CI -16.65 to 21.05; P = 0.82). The trial by Con-

quer compared docosahexaenoic acid (DHA) 400g/day and DHA

800 g/day also with no statistically significant difference in effect

(MD -6.80, 95% CI -41.87 to 28.27; P = 0.70). The trial by Li

2005a reported on sperm concentration at three months compar-

ing L-carnitine versus vitamin E + vitamin C with a statistically

significant difference (MD 15.50, 95% CI 12.49 to 18.51; P <

0.00001) in favour of vitamin E + vitamin C over L-carnitine.



Figure 21. Forest plot of comparison: 3 Antioxidant(s) versus antioxidant(s), outcome: 3.5 Sperm

concentration at 3 months or less.

Sperm concentration at six months

Two trials (Balercia 2005; Safarinejad 2009) reported on sperm

concentration at six months using five comparisons (Analysis 3.6;

Figure 22).




concentration at 6 months.

The trial by Balercia reported on two comparisons for this out-

come: L-acetyl carnitine + L-carnitine versus L-carnitine (MD -

8.13, 95% CI -24.42 to 8.16; P = 0.33) and L-acetyl carnitine +

L-carnitine versus L-acetyl carnitine (MD -2.17, 95% CI -17.40

to 13.06; P = 0.78). Neither of these comparisons showed any sta-

tistically significant difference in effect between the antioxidants.

Safarinejad 2009 reported on three comparisons. Selenium versus

N-acetyl cysteine showed no statistically significant difference in

effect. Selenium versus selenium + N-acetyl cysteine showed a

statistically significant difference favouring selenium + N-acetyl

cysteine (MD -4.50, 95%CI -6.90 to -2.10; P < 0.0002).

Safarinejad 2009 also reported on N-acetyl cysteine versus sele-

nium + N-acetyl cysteine. There was a statistically significant dif-

ference (MD -5.30, 95% CI -7.29 to -3.31; P < 0.00001) in favour

of selenium + N-acetyl cysteine.

Sperm concentration at nine months

Balercia (Balercia 2005) reported on the outcome of sperm con-

centration at nine months with two comparisons (Analysis 3.7;

Figure 23).




concentration at 9 months or more.

L-acetyl carnitine + L-carnitine versus L-carnitine showed no sta-

tistically significant difference in effect between the two antioxi-

dants (MD -6.13, 95% CI -18.44 to 6.18; P = 0.33).

L-acetyl carnitine + L-carnitine versus L-acetyl carnitine also

showed no statistically significant difference in effect between the

two antioxidants (MD 2.06, 95% CI -8.33 to 12.45; P = 0.70).

D I S C U S S I O N

Summary of main results

This systematic review and meta analysis aimed to investigate

whether supplemental antioxidants given to subfertile men made a

difference to the outcomes of live birth, pregnancy and the adverse

events of miscarriage or stillbirth. Seminal parameters were also

analysed. The comparisons used were antioxidants versus control

and head to head antioxidants.

In the antioxidant versus control comparison there was a statisti-

cally significant difference in effect in favour of antioxidants in the

live birth and pregnancy outcomes. These antioxidants did not ap-

pear to be associated with any increase in miscarriage. There were

however only three trials (Omu 1998; Suleiman 1996; Tremellen

2007) in the outcome of live birth. One of these trials Suleiman

1996 had drop outs. The reasons were explained but we were un-

aware of how many of the drop outs were from the treatment or

control group. Therefore we could not use intention-to-treat anal-

ysis for this trial.

Fifteen trials reported on pregnancy rate (Balercia 2005; Balercia

2009; Cavallini 2004; Galatioto 2008; Lenzi 2003; Lenzi 2004;

Omu 1998; Peivandi 2010; Rolf 1999; Safarinejad 2009a; Sigman

2006; Suleiman 1996; Tremellen 2007; Wang 1983; Zavaczki

2003) in the antioxidant versus control comparison and two (

Balercia 2005; Li 2005) in the head to head comparisons. Balercia

2005 was multi-armed and also reported pregnancy rate per couple

using the antioxidant versus control comparison.

There were no trials reporting on the outcome of stillbirth.

The data for the outcomes of total sperm motility at three, six and

nine months were unable to be pooled due to heterogeneity. A

random-effects model was used and sensitivity analysis was per-

formed. Heterogeneity remained moderate therefore we were not

able to pool this data and subtotals were used.

Sperm concentration at three months or less had high heterogene-

ity and did not show a statistically significant difference in effect

after sensitivity analysis was performed. The I2 statistic became

0% in the sensitivity analysis and therefore the data were able to

be pooled. The analysis of the outcome of sperm concentration

at six months also showed high heterogeneity. A random-effects

model was used and subtotals were used as the data were unable

to be pooled. The analysis of sperm concentration at nine months

showed a statistically significant difference in effect in favour of

the antioxidants over the control group. No heterogeneity was ev-

ident in this analysis. The high heterogeneity in the analysis of the

sperm parameters may in some way be due to the variations of the

types of antioxidants.

The main side effects reported were gastrointestinal and there

was no evidence that the antioxidant was more harmful than the

placebo.

It is difficult to draw conclusions from the head to head compar-

isons until there are more randomised trials that compare the same

antioxidants against controls. One antioxidant did not appear to

have any effect on pregnancy rate per couple or sperm parameters

over those of another antioxidant.

Overall completeness and applicability ofevidence



The live birth analysis in the antioxidant versus control group

was based on only three trials (Kessopoulou 1995; Omu 1998;

Suleiman 1996). The Suleiman trial had some imbalance in par-

ticipant numbers due to loss to follow up. The analysis remained

statistically significant when sensitivity analysis was performed on

the Suleiman trial.

Pregnancy rate evidence between antioxidants and control is in-

complete. Only 15 of 34 trials reported this outcome. Several of

these trials had high and selective losses to follow up. However

heterogeneity between the trials is low. The outcomes of sperm

motility and concentration also appear to be incomplete and not

applicable. Only 15 of 34 trials reported on sperm motility and

16 reported on sperm concentration

Two trials (Galatioto 2008; Tremellen 2007) used combined an-

tioxidants (three or more antioxidants) versus control.

Only one trial (Greco 2005) reported DNA fragmentation in the

comparison of antioxidants versus control therefore there were no

pooled data available for this outcome.

The adverse events of stillbirth, miscarriage and side effects appear

to be poorly reported.

The head to head comparison does not provide constructive in-

formation as there was no reason to pool direct comparisons. Sub-

grouping of antioxidants or different doses of antioxidants was un-

able to be performed in the treatment versus treatment groups as

there were only single trials analysing these differences. Therefore

this review was unable to show any difference in effect between

different antioxidants or different doses of the same antioxidant.

Quality of the evidence

All three studies reporting live birth (Kessopoulou 1995; Omu

1998; Suleiman 1996) had unclear methods of sequence genera-

tion and allocation concealment; one trial (Suleiman 1996) also

had some imbalance in numbers at analysis due to drop outs and

in another (Omu 1998) the comparison was no treatment and not

placebo.

Figure 23 (Figure 24) shows the review authors’ judgements about

the methodological quality of the trials included in this review.

All included trials were described as randomised however only

30% gave information on how the randomisation was achieved.

Allocation concealment was described in only 24% of the trials.

Blinding was better described with over 50% of the trials being

double and occasionally single blinded; 10% of trials stated that

there was no blinding. Incomplete outcome data were addressed

by most of the studies but selective reporting of outcomes was

unclear in the majority of trials.

Figure 24. Methodological quality graph: review authors’ judgements about each methodological quality

item presented as percentages across all included studies.

The seven trials that described their methods more thoroughly

(Galatioto 2008; Greco 2005; Peivandi 2010; Rolf 1999;

Safarinejad 2009; Sigman 2006; Tremellen 2007) can be seen

graphically in figure 24 (Figure 25).



Figure 25. Methodological quality summary: review authors’ judgements about each methodological

quality item for each included study.



Potential biases in the review process

Some bias in the review process may have arisen due to the inclu-

sion of trials that have had drop outs of participants of > 20% and

imbalances between the treatment and control groups.

Agreements and disagreements with otherstudies or reviews

Two reviews described the effects of L-carnitine and L-acetylcar-

nitine on subfertile men. The systematic review and meta-analysis

by Zhou (Zhou 2007) compared L-carnitine and L-acetylcarni-

tine therapy to placebo treatment and found significant improve-

ments in pregnancy rate and total sperm motility. No significant

difference was found in the outcome of sperm concentration. The

descriptive review by Patel (Patel 2008) discusses the improvement

in pregnancy rates with oral intake of antioxidants, however Patel

states that randomised controlled trials (RCTs) have not shown an

effect on sperm motility and that there is a need for more RCTs in

men with oxidative stress. These results were similar for the trials

reporting on L-carnitine and acetyl carnitine interventions in this

review.

Agarwal (Agarwal 2004) in an overview of the literature discusses

a range of antioxidants, and combinations of these, and their effect

on male subfertility. Agarwal notes that vitamin E and a combina-

tion of vitamin E with other antioxidants such as N-acetylcysteine,

vitamin A and fatty acids appears to improve pregnancy rates in

asthenozoospermic men. Carntines also appear to have an effect

on pregnancy rates. This review agrees with the carnitine discus-

sion but there were only single trials in the vitamin E interventions

versus placebo so a summary statistic for the outcome was unable

to be obtained.

Another review that was published recently (Ross 2010) also

showed improvement in pregnancy rate after antioxidant therapy.

A Cochrane review of antioxidants for female subfertility has been

published concurrently (Clarke 2009). The findings of both re-

views are consistent in that combined antioxidants improved preg-

nancy rate.

A U T H O R S ’ C O N C L U S I O N S

Implications for practice

When trying to conceive as part of an assisted reproductive pro-

gram, it may be advisable to encourage the male partner to take

an oral antioxidant supplement to improve his partner’s chance of

conceiving. More research is required to further substantiate these

conclusions.

Implications for research

In this review there were only three trials (two comparing antiox-

idant versus placebo and one versus no treatment) reporting on

live birth, the most important outcome from the perspective of

the couple experiencing difficulty with conception. Only one trial

reported on DNA fragmentation. A low degree of DNA fragmen-

tation is thought to increase a the likelihood of achieving a preg-

nancy. More well designed randomised controlled trials that report

on the outcomes of live birth, pregnancy, DNA fragmentation and

adverse events are needed.

Only two trials (Galatioto 2008; Tremellen 2007) used combined

antioxidants (three or more antioxidants) versus control. The re-

sults were in favour of the antioxidant over the control however

there is a need for more randomised controlled trials on this in-

tervention in order to make any conclusions on whether a combi-

nation of antioxidants would have statistical significant difference

over a single antioxidant versus placebo.

Further randomised controlled trials are needed to assess whether

one antioxidant is more effective than another by head to head

comparisons.

There is also a gap in the evidence for the assessment of different

doses of an antioxidant having differing effects. This review was

only able to include single trials measuring different doses and

therefore meta analysis of this comparison was unable to be per-

formed.

Evidence to date suggests that the side effect profile is low however,

as there were few studies, more data are required to determine any

adverse events and the side effect profile of these supplements.

A C K N O W L E D G E M E N T S

Cochrane Menstrual Disorders and Subfertility Group (MDSG).

I would like to make special mention of the MDSG editors who

were very thorough and helpful in editing this review.

Many thanks to the translators of the non-English trials - Ichiro

Omori (Japanese paper), Shaofu Li (two Chinese papers), Ivan

Sola (Bulgarian paper) and Pawel Kanturski (Polish paper) and Dr

Peviandi (Iranian paper).

Thanks also to Stephan Bontekoe who kindly helped with some

of the text.



R E F E R E N C E S

References to studies included in this review

Akiyama 1999 {published data only}

Akiyama M. In vivo scavenging effect of ethylcysteine on

reactive oxygen species in human semen. Japanese Journal

of Urology 1999; Vol. 90, issue 3:421–8.

Balercia 2005 {published data only}

Balercia G, Regoli F, Armeni T, Koverech A, Mantero F,

Boscaro M. Placebo-controlled double-blind randomized

trial on the use of L-carnitine, L-acetylcarnitine, or

combined L-carnitine and L-acetylcarnitine in men with

idiopathic asthenozoospermia. Fertility and Sterility 2005;

Vol. 84, issue 3:662–71.

Balercia 2009 {published data only}

Balercia G, Buldreghini E, et al.Coenzyme Q10 treatment

in infertile men with idiopathic asthenozoospermia: a

placebo-controlled, double-blind randomized trial. Fertility

and Sterility 2009;91(5):1785–92.

Biagiotti 2003 {published data only}

Biagiotti G, Cavallini G, Modenini F, Vitali G, Magli

C, Ferraretti A. Prostaglanadins pulsed down-regulation

enhances carnitine therapy performance in severe idiopathic

oligoasthenospermia. Human Reproduction 2003; Vol. 18

Suppl 1:202.

Cavallini 2004 {published data only}

Cavallini G, Ferraretti AP, Gianaroli L, Biagiotti G, Vitali G.

Cinnoxicam and L-carnitine/acetyl-L-carnitine treatment

for idiopathic and varicocele-associated oligoasthenospermia

[see comment]. Journal of Andrology 2004; Vol. 25, issue

5:761–70.

Ciftci 2009 {published data only}

Ciftci H, Verit A, Savas M, Yeni E, Erel O. Effects of

N-acetylcysteine on semen parameters and oxidative/

antioxidant status. Urology 2009;74(1):73–6.

Conquer 2000 {published data only}

Conquer JA, Martin JB, Tummon I, Watson L, Tekpetey F.

Effect of DHA supplementation on DHA status and sperm

motility in asthenozoospermic males. Lipids 2000;35(2):

149–54.

Dawson 1990 {published data only}

Dawson EB, Harris WA, Powell LC. Relationship between

ascorbic acid and male fertility. World Review of Nutrition

and Dietetics 1990; Vol. 62:1–26.

Galatioto 2008 {published data only}

Galatioto GP, Gravina GL, Angelozzi G, Sacchetti A,

Innominato PF, Pace G, et al.May antioxidant therapy

improve sperm parameters of men with persistent

oligospermia after retrograde embolization for varicocele?.

World Journal of Urology 2008; Vol. 26, issue 1:97–102.

Greco 2005 {published data only}

Greco E, Iacobelli M, Rienzi L, Ubaldi F, Ferrero S, Tesarik

J. Reduction of the incidence of sperm DNA fragmentation

by oral antioxidant treatment. Journal of Andrology 2005;

Vol. 26, issue 3:349–53.

Keskes-Ammar 2003 {published data only}

Keskes-Ammar L, Feki-Chakroun N, Rebai T, Sahnoun Z,

Ghozzi H, Hammami S, et al.Sperm oxidative stress and

the effect of an oral vitamin E and selenium supplement

on semen quality in infertile men. Archives of Andrology

2003; Vol. 49, issue 2:83–94.

Kessopoulou 1995 {published data only}

Kessopoulou E, Powers HJ, Sharma KK, Pearson MJ,

Russell JM, Cooke ID, et al.A double-blind randomized

placebo cross-over controlled trial using the antioxidant

vitamin E to treat reactive oxygen species associated male

infertility. Fertility and Sterility 1995; Vol. 64, issue 4:

825–31.

Lenzi 2003 {published data only}

Lenzi A, Lombardo F, Sgro P, Salacone P, Caponecchia L,

Dondero F, et al.Use of carnitine therapy in selected cases

of male factor infertility: a double-blind crossover trial [see

comment]. Fertility and Sterility 2003; Vol. 79, issue 2:

292–300.

Lenzi 2004 {published data only}

Lenzi A, Sgro P, Salacone P, Paoli D, Gilio B, Lombardo F,

et al.A placebo-controlled double-blind randomized trial

of the use of combined l-carnitine and l-acetyl-carnitine

treatment in men with asthenozoospermia [see comment].

Fertility and Sterility 2004; Vol. 81, issue 6:1578–84.

Li 2005 {published data only}

Li Z, Chen GW, Shang XJ, Bai WJ, Han YF, Chen B, et

al.A controlled randomized trial of the use of combined

L-carnitine and acetyl-L-carnitine treatment in men with

oligoasthenozoospermia. Zhong Hua Nan Ke Xue 2005;

Vol. 11, issue 10:761–4.

Li 2005a {published data only}

Li Z, Gu R, Liu Y, Xiang Z, Cao X, Han Y, et al.Curative

effect of L-carnitine supplementation in the treatment of

male infertility. Academic Journal of Shanghai Second

Medical University 2005; Vol. 25, issue 3:292–4.

Lombardo 2002 {published data only}

Lombardo F, Gandini L, Agarwal A, Sgro P, Dondero F,

Lenzi A. A prospective double blind placebo controlled

cross over trial of carnitine therapy in selected cases of male

infertility. Fertility and Sterility 2002; Vol. 78 Suppl 1:

68–9.

Merino 1997 {published data only}

Merino G, Martinez Chequer JC, Barahona E, Bermudez

JA, Moran C, Carranza-Lira S. Effects of pentoxifylline on

sperm motility in normogonadotropic asthenozoospermic

men. Archives of Andrology 1997; Vol. 39, issue 1:65–9.

Micic 1988 {published data only}

Micic S, Hadzi-Djokic J, Dotlic R, Tulic C. Pentoxifyllin

treatment of oligoasthenospermic men. Acta Europaea

Fertilitatis 1988; Vol. 19, issue 3:135–7.

Nozha 2001 {published data only}

Nozha CF, Leila AK, Zouhir S, Hanen G, Khled Z, Tarek

R. Oxidative stress and male infertility: comparative study



of combined vitamin E/selenium treatment versus vitamin

B. Human Reproduction 2001; Vol. 17, issue Abstract

book 1:111–2.

Omu 1998 {published data only}

Omu AE, Dashti H, Al-Othman S. Treatment of

asthenozoospermia with zinc sulphate: andrological,

immunological and obstetric outcome. European Journal of

Obstetrics, Gynecology, and Reproductive Biology 1998;

Vol. 79, issue 2:179–84.

Omu 2008 {published data only}

Omu AE, Al-Azemi MK, Kehinde EO, Anim JT, Oriowo

MA, Mathew TC. Indications of the mechanisms involved

in improved sperm parameters by zinc therapy. Medical

Principles and Practice 2008; Vol. 17, issue 2:108–16.

Peivandi 2010 {published data only}

Peivandi S, Abasali K, Narges M. Effects of L-carnitine on

infertile men’s spermogram; a randomised clinical trial.

Journal of Reproduction and Infertility 2010;10(4):331.

Rolf 1999 {published data only}

Rolf C, Cooper TG, Yeung CH, Nieschlag E. Antioxidant

treatment of patients with asthenozoospermia or moderate

oligoasthenozoospermia with high-dose vitamin C and

vitamin E: a randomized, placebo-controlled, double-blind

study [see comment]. Human Reproduction 1999; Vol. 14,

issue 4:1028–33.

Safarinejad 2009 {published data only}

Safarinejad MR, Safarinejad S. Efficacy of selenium and/

or N-acetyl-cysteine for improving semen parameters

in infertile men: a double-blind, placebo controlled,

randomized study. The Journal of Urology 2009;181(2):

741–51.

Safarinejad 2009a {published data only}

Safarinejad ME. Efficiacy of coenzyme Q10 on semen

parameters, sperm function and reproductive hormones in

infertile men. The Journal of Urology 2009;182:237–48.

Scott 1998 {published data only}

Scott R, MacPherson A, Yates RW, Hussain B, Dixon J. The

effect of oral selenium supplementation on human sperm

motility. British Journal of Urology 1998; Vol. 82, issue 1:

76–80.

Sigman 2006 {published data only}

Sigman M, Glass S, Campagnone J, Pryor JL. Carnitine for

the treatment of idiopathic asthenospermia: a randomized,

double-blind, placebo-controlled trial. Fertility and Sterility

2006; Vol. 85, issue 5:1409–14.

Suleiman 1996 {published data only}

Suleiman SA, Ali ME, Zaki ZM, el-Malik EM, Nasr MA.

Lipid peroxidation and human sperm motility: protective

role of vitamin E. Journal of Andrology 1996; Vol. 17, issue

5:530–7.

Tremellen 2007 {published data only}

Tremellen K, Miari G, Froiland D, Thompson J. A

randomised control trial examining the effect of an

antioxidant (Menevit) on pregnancy outcome during IVF-

ICSI treatment. The Australian & New Zealand Journal of

Obstetrics & Gynaecology 2007;47:216–21.

Wang 1983 {published data only}

Wang C, Chan CW, Wong KK, Yeung KK. Comparison

of the effectiveness of placebo, clomiphene citrate,

mesterolone, pentoxifylline, and testosterone rebound

therapy for the treatment of idiopathic oligospermia.

Fertility and Sterility 1983;40(3):358–65.

Wong 2002 {published data only}

Wong WY, Merkus HM, Thomas CM, Menkveld R,

Zielhuis GA, Steegers-Theunissen RP. Effects of folic acid

and zinc sulfate on male factor subfertility: a double-blind,

randomized, placebo-controlled trial. Fertility and Sterility

2002; Vol. 77, issue 3:491–8.

Zalata 1998 {published data only}

Zalata A, Christophe A, Horrobin D, Dhooge W, Comhaire

F. Effect of essential fatty acids and antioxidants dietary

supplementation on the oxidative DNA damage of the

human spermatozoa. ESHRE 14th annual meeting.

Goteborg, 1998:270–1.

Zavaczki 2003 {published data only}

Zavaczki Z, Szollosi J, Kiss S, Koloszar S, Fejes I, Kovacs L,

Pal A. Magnesium-orotate supplementation for idiopathic

infertile male patients: a randomized, placebo-controlled

clinical pilot study. Magnesium Research 2003;16(2):131–6.

References to studies excluded from this review

Cavallini 2004a {published data only}

Cavallini G, Ferraretti AP, Gianaroli L, Magli MC, Biagiotti

G, Vitali G. Cinnoxicam + carnitines for idiopathic

dyspermia. The 20th Annual Meeting of the European

Society of Human Reproduction and Embryology 2004:

i23–4.

Comhaire 2005 {published data only}

Comhaire FH, El Garem Y, Mahmoud A, Eertmans

F, Schoonjans F. Combined conventional/antioxidant

“Astaxanthin” treatment for male infertility: a double blind,

randomized trial. Asian Journal of Andrology 2005; Vol. 7,

issue 3:257–62.

Ebisch 2003 {published data only}

Ebisch IM, van Heerde WL, Thomas CM, van der

Put N, Wong WY, Steegers-Theunissen RP. C677T

methylenetetrahydrofolate reductase polymorphism

interferes with the effects of folic acid and zinc sulfate on

sperm concentration. Fertility and Sterility 2003; Vol. 80,

issue 5:1190–4.

Ebisch 2006 {published data only}

Ebisch IM, Pierik FH, DE Jong FH, Thomas CM,

Steegers-Theunissen RP. Does folic acid and zinc sulphate

intervention affect endocrine parameters and sperm

characteristics in men?. International Journal of Andrology

2006; Vol. 29, issue 2:339–45.

Elgindy 2008 {published data only}

Elgindy EA, El-Huseiny AM, Mostafa MI, Gaballah AM,

Amed TA. N-Acetylcysteine: Could it be an effective

adjuvant therapy in ICSI cycles. Fertility and Sterility

2008;90 Suppl 1(American Society for Reproductive



Medicine 64th Annual Meeting. November 8-12, 2008,

San Francisco CA):356 Abstract no: P738.

Micic 2001 {published data only}

Micic S, Lalic N, Bojanic N, Nale DJ. Oligospermic men

treated by carnitine. 17th World Congress on Fertility and

Sterility. Melbourne, 2001:38.

Nikolova 2007 {published data only}

Nikolova V, Stanislavov R, Vatev I, Nalbanski B, Punevska

M. Sperm parameters in male idiopathic infertility after

treatment with prelox. Akusherstvo i Ginekologiia 2007;

Vol. 46, issue 5:7–12.

Pawlowicz 2001 {published data only}

Pawlowicz P, Stachowiak G, Bielak A, Wilczynski J.

Administration of natural anthocyanins derived from

chokeberry (aronia melanocarpa) extract in the treatment

of oligospermia in males with enhanced autoantibodies to

oxidized low density lipoproteins (oLAB). The impact on

fructose levels. Ginekologia Polska 2001;72(12):983–8.

Pryor 2003 {published data only}

Pryor JL, Stacy L, Glass S, Campagnone J, Sigman M.

Randomized double blind placebo controlled trial of

carnitine for the treatment of idiopathic asthenospermia.

Fertility and Sterility 2003; Vol. 80 Suppl 3:48.

Rolf 1998 {published data only}

Rolf C. Antioxidant treatment with high dose vitamin

C and vitamin E of patients with asthenozoospermia a

randomized placebo controlled double blind study. ESHRE

14th annual meeting. Goteborg, 1998:72.

Stanislavov 2009 {published data only}

Stanislavov R, Nikolova V, Rohdewald P. Improvement of

seminal parameters with Prelox® : a randomized, double-

blind, placebo controlled, cross over trial. Phytotherapy

Research 2009;23:297–302. [DOI: 10.1002]

Tremellen 2006 {published data only}

Tremellen K, Froiland D, Miari G, Thompson J. A

randomised control trial examining the effect of an

antioxidant on sperm function pregnancy outcome during

IVF treatment. The Fertility Society of Australia 25th

Annual scientific meeting 2006 2006; Vol. 46 Suppl 2:A2.

Vicari 2001 {published data only}

Vicari E, Calogero AE. Effects of treatment with carnitines

in infertile patients with prostatovesiculoepididymitis and

elevated sperm oxidative stress. ESHRE 17th Annual

Meeting. Lausanne: Human Reproduction, 2001; Vol. 16

Suppl 1:106–7.

Vicari 2001a {published data only}

Vicari E, Rubino C, De Palma A, Longo G, Lauretta M,

Consoli S, Arancio A. Antioxidant therapeutic efficiency

after the use of carnitine in infertile patients with bacterial

or non bacterial prostato-vesiculo-epididymitis. Archivio

Italiano di Urologia, Andrologia 2001;73(1):15–25.

Zalata 1998a {published data only}

Zalata A, Christophe A, Horrbin D, Dhooge W, Comhaire

F. Protection of sperm function and DNA by essential fatty

acids and antioxidants dietary supplementation. Fertility

and Sterility 1998;70(3 Abstracts of 1998 Meetings):287.

References to studies awaiting assessment

Dimitriadis 2010 {published data only}

Dimitriadis F, Tsambalas S, Tsounapi P, Kawamura H,

Vlachopoulou E, Haliasos N, Gratsias S, Watanabe T, Saito

M, Miyagawa I, Sofikitis N. Effects of phosphodiesterase-

5 inhibitors on Leydig cell secretory function in

oligoasthenospermic infertile men: A randomized trial.

BJU International 2010;106(8):1181–1185.

Wang 2010 {published data only}

Wang YW, Yang SW, Qu CB, Huo HX, Li W, Li JD,

Chang XL, Cai GZ. L- carnitine: safe and effective for

asthenozoospermia. National Journal of Andrology 2010;16

(5):420–2.

References to ongoing studies

Gonzalez 2009 {unpublished data only}

Gonzalez Sanchez R. Assessment of the efficacy of dietary

supplement spermotrend in the treatment of male infertility.

ClinicalTrials.gov.

Kumar 2010 {unpublished data only}

Kumar R. Evaluation of oxidative stress as a cause for

idiopathic male infertility and the role of addyzoa.

ClinicalTrials.gov.

Revel 2006 {published data only}

Revel A. A preliminary study on effect of omega-3 on

human sperm. ClinicalTrials.gov. [CTG: NCT00479960]

Sadeghi 2008 {published data only}

Sadeghi M. Effects of coenzyme Q10 (CoQ10)

supplementation on semen quality and seminal oxidative

stress of idiopathic oligoasthenoteratozoospermic (iOAT)

infertile men. World Health Organization International

Clinical Trials Registry Platform Search Portal 2008.

[ISRCTN: ISRCTN29954277]

Tsafrir 2010 {published data only}

Tsafrir A. Is a carnitine based food supplement

(PorimoreTM) for infertile men superior to folate and zinc

with regard to pregnancy rates in intrauterine insemination

cycles?. Information obtained from ClinicalTrials.gov on

March 01, 2010.

Additional references

Agarwal 2003

Agarwal A, Said T. Role of sperm chromatin abnormalities

and DNA damage in male infertility. Human Reproduction

Update 2003;9(4):331–45.

Agarwal 2004

Agarwal A, Nallella K, Allamaneni S, Said T. Role of

antioxidants in treatment of male infertility: an overview of

the literature. Reproductive Biomedicine Online 2004;8(6):

616–27.



Aitken 2004

Aitken RJ, Koopman P, Lewis SE. Seeds of concern. Nature

2004;432(7013):48–52.

Aitken 2007

Aitken RJ, De Iuliis GN. Origins and consequences of

DNA damage in male germ cells. Reproductive Biomedicine

Online 2007;14(6):727–33.

Alvarez 2003

Alvarez 2003. Nuture vs nature: How can we optimise

sperm quality?. Journal of Andrology 2003;24(5):640–8.

Attia 2007

Attia AM, Al-Inany HG, Farquar C, Proctor M.

Gonatrophins for idiopathic male factor male subfertility.

Cochrane Database of Systematic Reviews 2004, Issue 4.

[DOI: 10.1002/14651858.CD005071.pub3; : ]

Boe-Hansen 2005

Boe-Hansen GB, Ersboll AK, Christensen P. Variability and

laboratory factors affecting the sperm chromatin structure

assay in human semen. Journal of Andrology 2005;26(3):

360–8.

Boe-Hansen 2006

Boe-Hansen GB, Fedder J, Ersboll AK, Christensen P. The

sperm chromatin structure assay as a diagnostic tool in the

human fertility clinic. Human Reproduction 2006;21(6):

1576–82.

Borini 2006

Borini A, Tarozzi N, Bizzaro D, Bonu MA, Fava L, Flamigni

C, Coticchio G. Sperm DNA fragmentation: paternal effect

on early post-implantation embryo development in ART.

Human Reproduction 2006;21(11):2876–81.

Bykova 2007

Bykova M, Athayde K, Sharma R, Jha R, Sabanegh E,

Agarwal A. Defining the reference value of seminal reactive

oxygen species in a population of infertile men and normal

healthy volunteers. Fertility and Sterility 2007;88 Suppl 1

(P-597):305.

Clarke 2009

Clarke J, Showell MG, Hart RJ, Agarwal A, Gupta S.

Antioxidants for female subfertility. Cochrane Database

of Systematic Reviews 2009, Issue 2. [DOI: 10.1002/

146518858]

Comhaire 2000

Comhaire FH, Christophe AB, Zalata AA, Dhooge WS,

Mahmoud AM, Depuydt CE. The effects of combined

conventional treatment, oral antioxidants and essential fatty

acids on sperm biology in subfertile men. Prostaglandins,

Leukotrienes, and Essential Fatty Acids 2000;63(3):159–65.

Dias 2006

Dias S, McNamee R, Vail A. Evidence of improving quality

of reporting of randomised controlled trials in subfertility.

Human Reproduction 2006;21(10):2617–27.

El-Taieb 2009

El-Taieb MAA, Herwig R, Nada EA, Greilberger J,

Marberger M. Oxidative stress and epididymal sperm

transport, motility and morphological defects. European

Journal of Obstetrics, Gynecology, and Reproductive Biology

2009;144 Suppl 1:199–203.

Eskenazi 2005

Eskanazi B, Kidd SA, Marks AR, Sloter E, Block G,

Wyrobeck AJ. Antioxidant intake is associated with semen

quality in healthy men. Human Reproduction 2005;20(4):

1006–12.

Evenson 2006

Evenson D, Wixon R. Meta-analysis of sperm DNA

fragmentation using the sperm chromatin structure assay.

Reproductive Biomedicine Online 2006;12(4):466–72.

Evenson 2007

Evenson DP, Kasperson K, Wixon RL. Analysis of sperm

DNA fragmentation using flow cytometry and other

techniques. Society for Reproduction and Fertility 2007;65

Suppl:93–113.

Higgins 2006

Higgins JPT, Green S, editors. Cochrane Handbook for

Systematic Reviews of Interventions 4.2.6 (updated Sept

2006). The Cochrane Library Issue 4 Sept 2006. Chichester

UK: John Wiley and Sons Ltd, 2006.

Li 2006

Li Z, Wang L, Cai J, Huang H. Correlation of sperm DNA

damage with IVF and ICSI outcomes: a systematic review

and meta-analysis. Journal of Assisted Reproduction and

Genetics 2006;23(9-10):367–76.

Omu 2008

Omu AE, Al-Azemi MK, Kehinde EO, Anim JT, Oriowo

MA, Mathew TC. Indications of the mechanisms involved

in improved sperm parameters by zinc therapy. Medical

Principles and Practice 2008;17:108–16.

Patel 2008

Patel SR, Sigman M. Antioxidant therapy in male infertility.

Urologic Clinics of North America. 2008;35(2):319–30.

[MEDLINE: 18423251]

Ross 2010

Ross C, Morriss A, Khairy M, Khalaf Y, Braude P,

Coomarasamy A, El-Toukhy T. A systematic review of the

effect of oral antioxidants on male infertility. Reproductive

Biomedicine Online 2010;20(6):711–23. [PUBMED:

20378409]

Sheweita 2005

Sheweita S, Tilmisany A, Al-Sawaf H. Mechanisms of male

infertility: Role of antioxidants. Current Drug Metabolism

2005;6(5):495–501.

Sikka 1995

Sikka S, Rajasekaran M, Hellstrom W. Role of oxidative

stress and antioxidants in male infertility. Journal of

Andrology 1995;16(6):464–8.

Stankiewicz 2003

Stankiewicz M, Norman R. Zinc for male infertility.

Cochrane Database of Systematic Reviews 2003, Issue 4.

[DOI: 10.1002/14651858.CD004633]



Tarozzi 2007

Tarozzi N, Bizzaro D, Flamigni C, Borini A. Clinical

relevance of sperm DNA damage in assisted reproduction.

Reproductive Biomedicine Online 2007;14(6):746–57.

Tournaye 2006

Tournaye H. Evidence-based management of male

subfertility. Current Opinion in Obstetrics & Gynecology

2006;18:253–9.

Tremellen 2008

Tremellen K. Oxidative stress and male infertility - a clinical

perspective. Human Reproduction Update 2008;14(3):

243–58.

Wathes 2007

Wathes DC, Abayasekara DR, Aitken RJ. Polyunsaturated

fatty acids in male and female reproduction. Biology of

Reproduction 2007;77(2):190–201.

Zhou 2007

Zhou X, Liu F, Zhai S. Effect of L-carnitine and/or L-

acetyl-carnitine in nutrition treatment for male infertility: a

systematic review. Asia Pacific Journal of Clinical Nutrition

2007;16 Suppl 1:383–90. [MEDLINE: 17392136]∗ Indicates the major publication for the study



C H A R A C T E R I S T I C S O F S T U D I E S

Characteristics of included studies [ordered by study ID]

Akiyama 1999

Methods Randomised crossover trial. Single centre

Participants Country: Japan

Male infertility

Mean age: 36 years (treatment group age range 24-49, control 30-37)

n=10 recruited

Inclusion criteria: Male infertility (ROS >5*10000 counts/10000000 viable spermato-

zoa)

Exclusion criteria: Azoospermia, pyospermia

Duration of study: 8 months

Interventions Ethylcysteine 600mg/day for 3 months (n=5)

versus

Vitamin E 600mg/day (n=5)

With a one month wash out, then crossover for another 3 months. Only data from the

first phase was used in data analysis

Outcomes Semen parameters

Notes In Japanese. Data extraction translated by Ichiro, a colleague of Samantha Roberts, 29/

01/09

Author contacted ’no further information is available’.

Risk of bias

Bias Authors’ judgement Support for judgement

Random sequence generation (selection

bias)

Unclear risk “Patients were divided randomly”

Allocation concealment (selection bias) Unclear risk No details

Blinding (performance bias and detection

bias)

All outcomes

Unclear risk No details

Incomplete outcome data (attrition bias)

All outcomes

Low risk No incomplete outcome data

Selective reporting (reporting bias) Low risk No statement regarding funding

Other bias Unclear risk Can not definitively assess other bias



Balercia 2005

Methods Randomised trial, double blind. No details of randomisation or concealment

Participants Country: Italy

Infertile men recruited from an andrology clinic

mean age 30 (range 24-38 years)

n=60 recruited

Inclusion criteria: Primary infertility > 2 years after regular intercourse with a fertile

woman; 20-40 years of age; normal rheologic characteristics; sperm count >20 x 106/ml; sperm motility < 50%; normal sperm morphological features > 30%; seminal

WBC <1x106/ml; negative sperm culture and chlamydia and mycoplasma urealyticum;

normal serum gonadotropins; T, E2 and PRL; absence of infectious or genital disease;

no anatomic abnormalities of the genital tract; absence of systemic diseases or treatment

with other drugs within the 3 months before enrolment in the study. Absence of smoking,

alcohol or recreational drug use or of occupational chemical exposure.

Total duration of study 9 months

Interventions L carnitine 3g/day orally (n=15)

versus

L-acetyl carnitine 3g/day orally (n=15)

versus

L carnitine 2g/day + L-acetyl carnitine 1g/day (n=15)

versus

placebo (n=15)

Duration of treatment: 6 months


Notes

Risk of bias



bias)

Unclear risk “Placebo controlled double blind ran-

domised trial” No methods of randomisa-

tion mentioned



bias)

All outcomes

Low risk “double blind” study. Patients blinded but

no details as to who else, assume it is the

clinician


All outcomes

Low risk 1 withdrawal from the L carnitine 2g/day

+ L-acetyl carnitine 1g/day group

Selective reporting (reporting bias) High risk Pregnancy was not in the original list of

outcomes but was reported in the results



Balercia 2005 (Continued)


Balercia 2009

Methods Double blind, placebo controlled randomised trial

Participants Country: Italy (University of Marche, Ancona)

Infertile men recruited from andrology clinic

Mean age: 32 (range 27-32 years)

N= 60 men recruited

Inclusion criteria: Age 20-40 years, infertility >2 years, regular sexual intercourse with

a potentially fertile female; Normal rheologic characteristics (appearance, consistency

and liquefaction) of semen and volume and pH in normal range, sperm count >20 x 106/mL, sperm motility <50% (WHO 1999), normal morphology >30%, seminal white

blood cells <1 x 106/mL and a negative sperm culture and chlamydia and M.urealyticum

detection. Normal levels of gonadotropins absence of genital disease and anatomical

abnormalities of the genital tract including variocoele and antibodies. Absence of systemic

disease or treatment with other drugs within 3 months of being enrolled in the study.

Absence of smoking, alcohol and drug addiction and exposure to occupational chemicals.

Exclusion criteria: Transient decrease in semen quality during run in and those who had

sudden improvement in semen parameters during run in.

Interventions Coenzyme Q10 100mg 2x/day (n=30)

versus

placebo (n=30)


Outcomes Primary: Semen parameters

Secondary: Pregnancy rate

Notes

Risk of bias



bias)

Unclear risk “randomised” - no details. At end of trial

the paper mentions - “after opening ran-

domisation list” page 1789



bias)

All outcomes

Low risk “Double blind” - no details



Balercia 2009 (Continued)


All outcomes

Low risk “5 patients dropped out of the study” 2

from the treatment group and 3 from the

placebo group this was discovered after

opening the randomisation list at the end

of the study. Intention to treat was carried

out.

Selective reporting (reporting bias) High risk Pregnancy was not in the original list of out-

comes but was reported in the results, “al-

though pregnancy was not an end point for

this controlled study, because of many pos-

sible interferences, it is interesting to note

that six pregnancies occurred with patients

given CoQ10”


Biagiotti 2003

Methods Randomised study - conference proceeding

Participants Country: Italy, Andrology clinic in Bologna

Population: severe idiopathic oligoasthenospermia (sperm concentration >5000/µl)

Mean age: Group a and b 35 (range 30-40 years), Group c 31 (range 24-34)

N= 42

Inclusion criteria: severe idiopathic oligoasthenospermia (sperm concentration >5000/

µl)

Exclusion criteria: Genomic, hormonal or inflammatory diseases

Duration of study: ?

Interventions a-Acetyl-carnitine 1 gr/day + L-carnitine 2gr/day + cinnoxicam (n=14)

versus

b-ALC + LC (n=14)

versus

c-no therapy (n=14)

Duration of treatment: ?


Notes Conference abstract - no data given. Contacted authors but no reply re questions as yet.

Risk of bias



bias)

Low risk “randomised (1patient = 1 block) analy-

sis of variance” Was this at the time of se-



Biagiotti 2003 (Continued)

quence generation or at data analysis?

Allocation concealment (selection bias) Unclear risk Not mentioned


bias)

All outcomes

Unclear risk Not mentioned


All outcomes

Unclear risk Unclear

Selective reporting (reporting bias) Unclear risk Unclear


Cavallini 2004

Methods Randomised controlled trial.

Allocation concealment: anonymous colour coded boxes


Population: Idiopathic plus variocoele associated oligoasthenospermia (OAT)

Mean age: 34 years (range 27-40)

N= 325

Inclusion criteria: OAT men with deficiencies in all sperm patterns whose chief complaint

was primary couple infertility >12 months with regular intercourse. Normal sperm ap-

pearance, consistency, liquefaction, volume, pH. Female partner without fertility prob-

lems.

Exclusion criteria: Azoospermia, seminal white blood cell concentration more than

1000,000/mL, positive urethral chlamydia swab test, oligospermia < 5000,000mL, hor-

monal alterations, age >40 yrs, presence of anti sperm antibodies, drug, tobacco or alco-

hol abuse, ongoing medical treatments, presence of hydrocoele, diabetes,hypertension,

x ray exposure in previous 8 months, peptic ulcer, unexplained gastric pain, previous

hypersensitivity to NSAIDS or carnitines, carnitine metabolism deficiency, bilateral var-

iocoele, prostate abnormalities, previous or current testicular pathology, testicle echo-

graphic abnormalities.


Interventions Group 1: Placebo, starch tablets 2x/day + glycerine suppository (1 every 4 days) (n=47)

Group 2: L-carnitine 1x 2g/day plus acetyl-L-carnitine 500 x 2mg/day plus glycerine

suppository (n=39)

Group 3: L-carnitine 1x 2g/day plus acetyl-L-carnitine 500 x 2mg/day plus glycerine

suppository plus cinnoxicam suppository 1 x 30mg (every 4 days) n=(44). Cinnoxicam

is a non steroidal antiinflammatory therefore this arm (Group 3) was not included in

meta analysis as per protocol.




Cavallini 2004 (Continued)

Outcomes Primary: Sperm parameters

Secondary: Pregnancy, side effects

Notes Continuous data taken from Cavallini 2004a ’excluded conference abstract’ no data for

placebo group

unit of analysis variocoele’s therefore cannot extract data that were presented as median

(interquartile range)

Author contacted regarding uneven numbers and missing placebo and continuous data

Author replied that raw data were not available due to computer crash

Risk of bias



bias)

Unclear risk “the patients were randomised into 3

groups” no details of how randomisation

was carried out

Allocation concealment (selection bias) Low risk “drug placebos identical in appearance”,

“anonymized carnitine and cinnoxicam

and glycerine suppository containers; and

filled and sealed anonymous color coded

boxes”, “the color code was disclosed to

physicians by pharmacists and by IRB at

the end of the research”


bias)

All outcomes

Low risk “All study personnel and participants were

blinded to treatment assignment for the du-

ration of the study”


All outcomes

High risk 325 randomised but only 185 accounted

for. 55 drop outs from 185 i.e. 42%, 53

reasons given for the drop outs



Ciftci 2009

Methods Randomised controlled trial

Allocation concealment: Sealed envelopes

Participants Country: Turkey

Population: Men attending fertility clinic with idiopathic infertility. Normal sperm pa-

rameters

Mean age: Treatment group 33.1±4.5, Control 32.8±3.7 years

N=120 recruited



Ciftci 2009 (Continued)

Inclusion criteria: Men attending fertility clinic with idiopathic infertility. Normal sperm

parameters

Exclusion criteria: Cryptorchidism, vasectomy, abnormal liver functioning, smoking,

alcohol consumption


Interventions N-acetylcysteine 600mg/day (n=60)

versus

placebo (n=60)


Outcomes Primary outcomes: Total antioxidant capacity, peroxide levels, oxidative stress

Secondary outcomes: Other semen parameters

Notes Attempt made to contact author regarding data reported in SD’s or SE’s email sent

24.09.10

Risk of bias



bias)

Unclear risk “patients were randomly allocated to the

study group (60 men) or control group (60

men)”

No mention of how the randomisation was

carried out.

Allocation concealment (selection bias) Low risk “Using sealed envelopes, these patients

were randomly allocated...”


bias)

All outcomes

Low risk “The patients in the study and control

groups were unaware of whether they were

receiving the drug or placebo.”

? researchers blinded


All outcomes

Low risk All men recruited were analysed. No with-

drawals

Selective reporting (reporting bias) Unclear risk No statement of funding

Report includes all expected outcomes

Baseline data were similar for both groups




Conquer 2000

Methods Randomised placebo controlled trial. 3 arms

Participants Country: Canada

Population: healthy asthenozoospermic individuals who were patients of an infertility

clinic

Mean age: placebo=35.2, DHA 400mg=38.3, DHA 800mg=34.4

N=28

Inclusion criteria: Asthenozoospermic, sperm motility <50% of total sperm

Exclusion criteria: Not stated

Duration of study: Not stated

Interventions Fatty acid omega 3

Docosahexaenoic acid (DHA) 400mg/day (n=9)

versus

DHA 800mg/day (n=10)

versus

placebo (n=9)


Outcomes Sperm parameters

Notes Data with SEMs converted to SDs

Placebo arms split

Risk of bias



bias)

Unclear risk “The 28 subjects were randomly assigned

to ...”

Allocation concealment (selection bias) Unclear risk Not stated


bias)

All outcomes

Unclear risk Placebo capsules made with “corn oil/soy

oil” however blinding not stated.


All outcomes

Low risk All men randomised were in the analysis,

no drop outs. All specified outcomes were

reported

Selective reporting (reporting bias) Unclear risk Outcomes reported

Other bias Unclear risk Funding from Martek Bioscience corpora-

tion (also provided the placebo capsules)



Dawson 1990


Participants Country: USA

Population: males with sperm agglutination

Mean age: age range 25-45 years

N=30

Inclusion criteria: sperm agglutination over 25%, negative sperm antibodies, physically

normal, no inflammatory disease

Exclusion criteria: unclear

Duration of study: 4 weeks

Interventions Ascorbic acid (AA)1000mg (n=10)

versus

AA 200mg (n=10)

versus

placebo (n=10)

Duration of treatment: 3 weeks

Outcomes Seminal parameters

Notes Placebo numbers split by 2

Data were given in standard error converted to standard deviation

Risk of bias



bias)

Unclear risk “By random selection, three groups of 10 subjects each..”

Allocation concealment (selection bias) Unclear risk Not stated


bias)

All outcomes

Unclear risk “Each subject was told he was receiving AA and expected

improvement in sperm quality”


All outcomes

Low risk No drop outs

Selective reporting (reporting bias) Unclear risk All specified outcomes were reported

Other bias Unclear risk “supplement and placebo were provided by Hoffmann-

La Roche, Inc, Nutley, NJ.”



Galatioto 2008

Methods Randomised controlled, intention to treat, single centre study. Central allocation - phar-

macy, blinded

Power calculation performed


Population: Men with persistent oligospermia (5-20m/ml)

Mean age:Treatment group=32 years (27.5-35.5), Control=33(23-36)

N=42

Inclusion criteria: having performed a retrograde embolization with concomitant

oligospermia, persistent oligospermia and infertility > 12 months

Exclusion criteria: smoking, alcohol consumption, taking any fertility drugs within 3

months prior to the study, serious medical or psychiatric condition, abnormal hormonal

profile, sperm infection

Interventions N-acetylcysteine (NAC) 600mg and vitamins-minerals (Vit C, Vit E, Vit A, thiamine,

riboflavin, piridoxin, nicotinamide, pantothenate, biotin, cyanocobalamin, ergocalcif-

erol, calcium, magnesium, phosphate, iron, manganese, copper, zinc. (n= 20)

versus

no treatment (n=22)

Duration: 12 months after end of study which ran for 90 days

Outcomes Primary: seminal parameters

Secondary: pregnancy and adverse effects

Notes Attempted to contact author regarding median data. No response as yet.

Risk of bias



bias)

Low risk “Subjects were randomly assigned to either

antioxidant therapy or no medical therapy.

Randomisation number was assigned by

random allocation software using a block

randomisation design”

Allocation concealment (selection bias) Low risk ’All steps of randomisation process were

performed blindly in the pharmacy of our

hospital.’


bias)

All outcomes

High risk Control is no treatment


All outcomes

Low risk “intention to treat”

Selective reporting (reporting bias) Low risk Does not appear to be any selective report-

ing



Galatioto 2008 (Continued)


Greco 2005

Methods Double blind randomised controlled trial. Trialists and patients blinded. Methods were

unclear

Participants Country: France

Population: infertile males

Mean age: ?

N=64

Inclusion criteria: Tunel assay showed a presence of fragmented DNA≥15%of ejaculated

spermatozoa

Exclusion criteria: Variocele, genitourinary inflammation, infection, smoking

Duration of study: ?

Interventions Vitamin C 500mg 2x/day + vitamin E 500mg 2x/day (n=32)

versus

placebo (n=32)



Notes

Risk of bias



bias)

Low risk “The study participants were randomised

into 2 groups”

Allocation concealment (selection bias) Unclear risk No mention of allocation concealment


bias)

All outcomes

Low risk “The study was double-blinded with both

the authors and the patients unaware of

which of the patients was in the treatment

or control arm of the study”


All outcomes

Low risk All specified outcomes are assessed. No

drop outs


ing




Keskes-Ammar 2003

Methods Randomised controlled trial - open labelled

Participants Country: Tunisia

Population: Infertile men

Mean Age: 35.5±6.8 (SD)

Recruited: N=78

Randomised: N=54

Inclusion criteria: Infertile men who had been married one year

Exclusion criteria: ?


Interventions Vitamin E (400mg/day) + selenium (225mg/day) for 3 months (n=12)

versus

vitamin B (4.5g/day) (n=8)



Notes Attempted to contact authors regarding high attrition rate >50% ?78 men randomised or

78 recruited then only 54 (28 in intervention and 26 in control) Then only 20 analysed

due to non-compliance.

Risk of bias



bias)

Low risk ”Randomisation was performed with ran-

dom numbers“ and the numeric code was

withheld from researchers and patients”

Allocation concealment (selection bias) Unclear risk open label


bias)

All outcomes

Unclear risk “The trial was randomised and open” How-

ever “the numeric code was withheld from

researchers and patients”


All outcomes

Low risk High attrition rate was due to non-compli-

ance, no intention to treat.

Selective reporting (reporting bias) Unclear risk MDA post treatment has no SD no expla-

nation




Kessopoulou 1995

Methods Double blinded randomised placebo cross over trial


Participants Country: UK, Sheffield

Population: Men with high levels of reactive oxygen species (ROS) attending Obstetrics

and Gynecology department for infertility

Couples were undergoing IVF

Mean Age: ? Median age: 32 years

Recruited: N= 30

Inclusion criteria: Attending fertility clinic, high levels of ROS in semen. Female partner

has tubal patency and is ovulating

Exclusion criteria: Men with antisperm antibodies, >20% spermatozoa with Ig (immuno

globin A) and/or IgG antibodies and sperm concentration <5x 06 mL

Duration of study: 2 years

Interventions Vitamin E 300mg 2x/day (n=15)

versus

identical placebo (n=15)


Outcomes Primary outcomes: Semen parameters

Secondary outcomes: Adverse effects. Live birth

Notes Attempted to contact author regarding median data, no response as yet

Only first phase data used in analysis

Risk of bias



bias)

Unclear risk “The study was a randomised double blind

placebo controlled trial”. “The randomisa-

tion was performed by the manufacturer”

Allocation concealment (selection bias) Unclear risk “The randomisation was performed by the

manufacturer”


bias)

All outcomes

Low risk “the code was blind for the researcher and

patients. The code was broken at the end

of the trial”


All outcomes

Low risk All outcomes are reported


ing

Other bias Unclear risk Funding grant by EEC. Tablets provided

by pharmaceutical company



Lenzi 2003

Methods Randomised placebo controlled, double blind crossover trial.



Population: Male factor infertility - oligoasthenoteratozoospermia (OAT).

Mean age: ? Range: 20-40 years

N=100

Inclusion criteria: Men are aged between 20-40 years with infertility lasting longer than

2 years. Regular sexual intercourse with a gynaecologically normal female partner with

no female infertility. Absence of endocrine disease, genital infections, obstructive cryp-

torchism, antisperm antibodies, normal sperm parameters with no significant differences

after 3 tests. Mild oligospermia. Sperm concentration 10-20 x 106/mL and motility 10-

30%

Exclusion criteria: Not mentioned

Duration of study:10 months

Interventions L-carnitine 2g/day (n=43)

Versus

placebo (n=43)


Outcomes Semen parameters and pregnancy rate

Notes First phase data only used in analysis

Attempted to contact author regarding standard deviations, how many were in each

group for the 1st phase and how many of the 4 who went to assisted reproduction did

so in the 1st phase and what do they mean by 172 cycles. No response yet.

Risk of bias



bias)

Unclear risk “we report on a randomised placebo con-

trolled cross over trial”. No mention of

method of randomisation

Allocation concealment (selection bias) Unclear risk No mention


bias)

All outcomes

Unclear risk Double blinded. “seemingly identical

placebo”


All outcomes

Low risk 14 withdrew - 4 went onto assisted re-

production, 6 did not return for 2nd pe-

riod and 4 due to pregnancy in first phase.

Therefore should only be ?4 at the most lost

from 1st phase. No intention to treat

All withdrawals accounted for for whole

trial however how many were lost in the



Lenzi 2003 (Continued)

first phase in first phase

Selective reporting (reporting bias) Unclear risk Although all outcomes are reported but no

standard deviations given

Other bias Unclear risk Funding stated - University grant. Tablets

from Sigma Tau SRL

Lenzi 2004

Methods Placebo controlled, double blind randomised trial. No mention of method of randomi-

sation or allocation concealment

“When codes were broken at the end of the study”



Population: Infertile males with oligoasthenoteratozoospermia

Mean age: Not stated. Age range 20-40 years

N=60


Inclusion criteria: oligoasthenoteratospermia, age between 20-40 years, infertility >2years

with regular intercourse. No endocrine disease, cryptorchidism, genital infections/ob-

structions, variocoele or testicular hypertrophy, antisperm antibodies

Exclusion criteria: None


Interventions L-carnitine 2g/day + L-acetyl-carnitine 500mg 2x/day (n=30)

versus

placebo (n=26)


Outcomes Semen parameters and pregnancy rate

Notes Attempted to contact author regarding 8 month follow up data. No reply as yet.

Risk of bias



bias)

Unclear risk “placebo controlled double blind ran-

domised trial”

Allocation concealment (selection bias) Unclear risk Mentions coding - “When codes were bro-

ken at the end of the study”


bias)

All outcomes

Low risk Double



Lenzi 2004 (Continued)


All outcomes

Unclear risk 4 men withdrew from the placebo group.

60 randomised 56 analysed. No intention

to treat



Li 2005

Methods Double blinded randomised parallel trial

Participants Country: Eastern China

Population: infertile men with oligoasthenospermia

Mean Age: Treatment 30±5.5 (23-45 years), Control 32±3.5 (24-46 years)

N=150

Inclusion criteria: No smoking or alcohol. Any fertility medication needed to be stopped

2 weeks before

Exclusion criteria: Nil

Duration: 3 months

Interventions L-carnitine 2g/day + acetyl-L-carnitine 1g/day (n=85) (90 with intention to treat)

versus

vitamin E (100 mg tid) + vitamin C (100mg tid) (n=53) (60 with intention to treat)


Outcomes Seminal parameters and pregnancy rate per couple

Notes Withdrawal: 5 from treatment group and 7 from control

Query whether randomised as there is imbalance between the groups. Contact author

re methods of randomisation (large imbalance of numbers), concealment and whether

SD or SE’s used and query that this is the same trial as Li 2005a

Translated by Shaofu Li 10/11/08

Risk of bias



bias)

Unclear risk Randomised controlled trial. Methods not

described. Unexplained differences in the

number of men in the treatment and con-

trol groups

Allocation concealment (selection bias) Unclear risk Allocation concealment not described


bias)

All outcomes

Low risk Double



Li 2005 (Continued)


All outcomes

High risk Unexplained imbalance between the num-

ber of men randomised into the treatment

and control groups

Selective reporting (reporting bias) Unclear risk Unclear whether data given in standard de-

viations or standard errors

Other bias Unclear risk Unexplained imbalance between the num-

ber of men randomised into the treatment

(n90) and control groups (n60)

Li 2005a

Methods Randomised trial. No information on concealment

Participants Country: Eastern China

Population: Infertile men with oligoasthenospermia

Mean age: 29±3.5 (23-40 years)

N=80

Inclusion criteria: No smoking or alcohol. Any fertility medication needed to be stopped

2 weeks before

Exclusion criteria: Nil

Duration: Not stated

Interventions L-carnitine 2g/day (n=40)

versus

vitamin E 100mg + vitamin C 100mg tid (n=40)


Outcomes Seminal parameters and pregnancy

Notes Attempted to contact author re methods of randomisation, concealment and whether

SD or SE’s used and whether this is the same trial as Li 2005. Also asked whether there

were any data on pregnancy rate. Translator replied 22.09.09 no pregnancy data were

available in the text of the trial.

Translated by Shaofu Li 10/11/08

Risk of bias



bias)

Unclear risk No mention of methods of randomisation




Li 2005a (Continued)


bias)

All outcomes

Unclear risk No mention of blinding


All outcomes

Unclear risk Withdrawal: 8 from treatment (n=32) and

9 from control (n=31). 21% loss to follow

up. No intention to treat

Selective reporting (reporting bias) High risk No data on pregnancy outcome


Lombardo 2002

Methods Randomised controlled crossover trial


Population: male infertility, oligoasthenospermia

Mean age: Not stated

N=100

Inclusion criteria: Age 20-40 years. Infertility > 2 years. 3 baseline semen analysis demon-

strating concentration 10-20 106/mL , %motility 10-30%, forward progression <15%,

abnormal morphological forms <70%, curvilinear velocity 10-30/second + linearity <4

Exclusion criteria: not mentioned

Duration: 10 months

Interventions L-carnitine 2g/day (n=?)

versus

placebo (n=?)



Notes Abstract only

Attempted to contact author re 1st phase data, outcomes, randomisation, concealment

and whether there was a full publication of the trial.

Risk of bias



bias)

Unclear risk randomised -“all patients had an initial 2

months run in period and then randomised to

2 months of carnitine or placebo.”




Lombardo 2002 (Continued)


bias)

All outcomes

Low risk “double blind crossover trial”


All outcomes

Unclear risk 86 patients completed the trial out of 100.

Need to see full trial for the reasons for with-

drawals and intention to treat


Other bias Unclear risk Funding stated - “support: None”

Merino 1997


Participants Country: Mexico

Population: Male idiopathic asthenozoospermia attending a fertility clinic

Mean age: 30.8±6 (20-40 years)

N=47

Inclusion criteria: Free of urogenital symptoms, idiopathic asthenozoospermia, not re-

ceived drugs in prior 6 months and healthy

Exclusion criteria: Variocoele, inflammatory diseases, endocrine disorders


Interventions Pentoxifylline 1200mg - 400mg/3xday (n=25)

versus

placebo (n=22)

Duration of intervention: 6 months

Outcomes Seminal parameters and hormonal assays

Notes Attempted to contact author to ask if had data in means + SD and not medians + range

as published. Letter sent 15.09.09. Letter returned to sender.

Risk of bias



bias)

Unclear risk “The 47 men were divided at random”



bias)

All outcomes

Unclear risk No mention of blinding however the trial is placebo con-

trolled



Merino 1997 (Continued)


All outcomes

Unclear risk No withdrawals

Selective reporting (reporting bias) Unclear risk ?all outcomes reported however seminal outcomes re-

ported in medians


Micic 1988


Methods not stated. No mention on methods of concealment

Participants Country: Belgrade, Hungary

Population: idiopathic oligoasthenospermia

Mean age:29±2 in treatment group, 26±3 in control group

N=90

Inclusion criteria: idiopathic oligoasthenospermia and no pregnancy for 2 years

Exclusion criteria: Variocoele, inflammatory diseases, endocrine disorders


Interventions Pentoxifylline 1200mg/day (n=51)

versus

no treatment (n=39)



Notes Attempted to contact author regarding extractable data for pregnancy rate plus methods

of of randomisation and concealment also don’t know if adverse events are single or

multiple events. No reply as yet.

Risk of bias



bias)

Unclear risk “A randomised group of 90 men”



bias)

All outcomes

High risk No mention of blinding


All outcomes

Unclear risk Don’t know if adverse events are single or

multiple. Pregnancy data not extractable



Micic 1988 (Continued)

Selective reporting (reporting bias) Unclear risk All randomised were analysed


Nozha 2001

Methods Randomised comparative study

No mention of allocation concealment

Abstract only

Participants Country: Tunisia

Population: Infertile males with oligoasthenoteratozoospermia

Mean age: not stated

N=?

Inclusion criteria: males with oligoasthenoteratozoospermia.

Exclusion criteria: none mentioned

Duration of study: not stated

Interventions Vitamin E (400mg) + selenium (200mµg)/day (n=12)

versus

vitamin B (B2, B6 and B12) (n=8)



Notes Attempted to contact authors regarding methods of randomisation and data - no ex-

tractable data from the abstract. No reply as yet.

Risk of bias



bias)

Unclear risk “In a prospective randomised comparative

study”



bias)

All outcomes



All outcomes

Unclear risk Unclear





Omu 1998


Open trial - control is no treatment

Participants Country: Kuwait

Population: Men with asthenozoospermia attending infertility and andrology clinic

Mean age: 37.8±7.9 in treatment group, 38.1±8.2 in control

N= 100

Inclusion criteria: Men with asthenozoospermia. Spermatozoal motility impaired with

>40% non mobile sperm. Have been trying to conceive for at least one year. Plus no

obvious female factor

Exclusion criteria: None mentioned


Interventions Zinc 250mg 2xday (n=49)

versus

no treatment (n=48)



Notes Attempted to contact authors regarding methods randomisation and concealment ques-

tioned. No reply as yet.

Risk of bias



bias)

Unclear risk Randomised. “100 men with Astheno-

zoospermia were randomised into two

groups”



bias)

All outcomes



All outcomes

Unclear risk 100 men randomised, 97 analysed, drop

outs are accounted for

Other bias Unclear risk Funding - Kuwait University



Omu 2008

Methods Randomised controlled 4 armed trial, open as one arm of the trial is no therapy

Participants Country: Kuwait

Population: Men with Asthenozoospermia attending infertility clinic in Kuwait

Mean age: 35±1

N= 45

Inclusion criteria: Asthenozoospermia with normal sperm concentration (20-250mill/

ml) but with 40% or more immotile sperm

Exclusion criteria: Asthenozoospermia but sperm concentration of <20 mill/ml

Duration of study: No stated

Interventions Zinc 200mg 2x/day (n=11)

versus

zinc 200mg + vitamin E 10mg 2x/day (n=12)

versus

zinc 200mg + vitamin E 10mg + vitamin C 5mg 2x/day (n=14)

versus

no therapy (n=8)

Duration of intervention: 3 months


Notes Attempted to contact author re methods of randomisation - states that “8 men served as

non- therapy control”. No reply as yet.

Risk of bias



bias)

Unclear risk “the 45 asthenozoospermic men were ran-

domised into four groups”



bias)

All outcomes



All outcomes

Low risk All outcomes are reported. No drop outs

Selective reporting (reporting bias) Unclear risk Appears to be free of selective reporting




Peivandi 2010

Methods Double blind randomised crossover trial

Participants Country: Iran

Population: Infertile men with at least two abnormal spermiograms

N=30

Exclusion criteria: variocoele, testicular atrophy, ejaculatory disorders, use of medications,

azoospermia, endocrinological disorders, ICSI candidacy or other causes of infertility

Duration of 1st phase: 8 weeks

Interventions L-carnitine (2g/day)

versus

placebo


Notes Abstract in English, full text in Arabic. Contacted the author and he is filling out the data

extraction sheets. Author responded but data queries remain contacted again re SD’s and

pregnancies in 1st phase of cross over. Author responded saying that the data was given

in SD’s and there were 3 pregnancies in the 1st phase.

Risk of bias



bias)

Unclear risk ”patients were randomly allocated to two

groups of A and B“

Allocation concealment (selection bias) Low risk ”sealed opaque envelopes“


bias)

All outcomes

Low risk ”Double blind“ ”outcome assessor was

blinded“


All outcomes

Unclear risk ’loss to follow up was not accounted for”

Selective reporting (reporting bias) Unclear risk “Pregnancy was not our major goal but when

we found a positive pregnancy test after treat-

ment with carnitine, we reported the results”

Standard deviations appear to be unusual




Rolf 1999

Methods Randomised placebo controlled double blind study



Participants Country: Munster Germany

Population: men with infertility for over one year.

Mean age: treatment 36.1±5.0, placebo 35.2±4.8

N= 33

Inclusion criteria: Asthenozoospermia (<50% motile) diagnosed after 2 examinations,

normal or reduced sperm concentration (>20 x 106 per ejaculate) and without infection

of access glands



Interventions Vitamin C 1000mg + vitamin E 800mg/day (n=15)

versus

placebo (n=16)



Secondary: Pregnancy rate and adverse effects

Notes Contacted author about the allocation concealment and pregnancy and adverse effects

were outcomes in their protocol. Rolf replied saying that pregnancy and adverse effects

were stated in the protocol.

Risk of bias



bias)

Low risk “Randomisation was performed with ran-

dom numbers without further stratification

by the pharmacist and the code was with-

held from researchers and patients”

Allocation concealment (selection bias) Unclear risk Pharmacist performing randomisation and

code withheld from patients and re-

searchers. However no mention of type of

containers or envelopes


bias)

All outcomes

Low risk Double - patients and researchers


All outcomes

Low risk All data reported. 2 patients withdrew form

the trial - “results from two patients were

rejected from analysis.” 1 from the treat-

ment group due to poor compliance and 1

from the placebo group due to genital tract



Rolf 1999 (Continued)

infection. Intention to treat

Selective reporting (reporting bias) Low risk All semen outcomes reported and author

states (email 22.09.09) that pregnancy and

adverse effects were set a priori in the pro-

tocol

Other bias Unclear risk Funding stated - Health Ministry

Safarinejad 2009

Methods Double blind placebo controlled randomised study. Randomised using permuted blocks

Allocation concealment: Sealed envelopes

Blinding: Double, identical coating of tablets


Participants Country: Iran

Population: Idiopathic oligoasthenoteratospermia, asthenospermia or teratospermia of

2 years duration

Mean age: 31 years (25-48 years)

Recruited: N= 548

Randomised: N= 468

Inclusion criteria: Sperm count >5 x 106/ml, over 2 years of failed conception, no female

fertility problems, no history of possible cause for male infertility

Exclusion criteria: Abnormal testes, history of cancer or chemotherapy, testosterone or

antiandrogen use, use of selenium or N-acetyl-cystine supplements, abnormal hormone

levels, genital disease, genital inflammation or variocoele, history of genital surgery, major

surgery, central nervous system injury, a known sperm defect or retrograde ejaculation. Y

chromosome abnormalities, sexually transmitted disease, genitourinary infection, leuko-

cytospermia, smoking, any environmental exposures to reproductive toxins. Medical,

neurological or psychological problems. A history of drug or alcohol abuse, hepatobil-

iary disease or significant renal insufficiency. Any endocrine abnormality, a body mass

index (BMI) of 30kg/m2 or over, participation in another investigational study and a

likelihood of being unavailable for follow up.


Interventions Selenium 200 µg/day (n=116)

versus

N-acetylcysteine 600mg/day (n=118)

versus

selenium 200 µg/day + N-acetylcysteine 600mg/day (n=116)

versus

placebo (n=118)

Duration of treatment: 26 weeks or 6.5 weeks

Analysed: n= 105 in selenium group (loss 11), n= 106 in placebo group (loss 12), n=105

in N-acetylcysteine group (loss 13) and n= 104 in selenium + N-acetylcysteine group

(loss 12)



Safarinejad 2009 (Continued)

Outcomes Primary outcome: Semen parameters

Secondary outcomes: adverse events

Notes Attempted to contact authors regarding side effect data that had not yet been added to

the review due to the query of multiple comparisons. Also to ask whether data is in SD

or SE as requested by statistician 24.09.10.

Risk of bias



bias)

Low risk “randomisation table generated by the

method of random permuted blocks. Pa-

tient randomisation numbers were allo-

cated to each site in ascending sequence in

blocks.”

Allocation concealment (selection bias) Low risk “Assignment to treatment groups was per-

formed using a sealed envelope technique.”


bias)

All outcomes

Low risk “Eligible patients were randomly assigned

to double blind..”

“Placebo pills were coated with titanium

oxide to ensure an identical appearance and

smell.”


All outcomes

Low risk All withdrawals were accounted for in each

treatment group. Withdrawal was mainly

due to withdrawal of consent followed by

lost to follow up and lastly for reasons of

missing data. No intention to treat

Selective reporting (reporting bias) Low risk The published report includes all expected

outcomes


Safarinejad 2009a

Methods Randomised controlled trial, double blind

Allocation concealment: Not mentioned


Participants Country: Tehran, Iran

Population: Infertile males between 21 and 42 years with idiopathic oligoasthenoter-

atospermia.

Mean age: Treatment group 28±9, Placebo 28±10. (Range 21-42 years)

Recruited: N= 268



Safarinejad 2009a (Continued)

Randomised: N=212

Inclusion criteria: Minimum 2 years unprotected intercourse with 2 years unwilling

childlessness. male infertility diagnosed if 1 or more standard semen parameters were

below cutoff levels accepted by World Health Organisation (WHO). A fertile female

partner. No known medical condition that could account for infertility, testicular volume

12 ml or greater. No medical therapy for at least 12 weeks before the study begins. Only

patients seeking medical attention for infertility were included.

Exclusion criteria: Azoospermia or severe oligospermia (sperm count less than 5 million/

ml. An history of epypidymo-orchitis, prostatitis, genital trauma, testicular torsion, in-

guinal or genital surgery. Any genital or central nervous system disease, endocrinopathy,

cytotoxic drugs, immunosuppressants, anticonvulsives, androgens, antiandrogens, a re-

cent history of Sexually transmitted disease. Psychological or physiological abnormalities

that would impair sexual functioning or ability to produce sperm samples. Drug, alco-

hol or substance abuse. Liver disease, renal insufficiency or chromosome abnormalities.

occupational and environmental exposures to reproductive toxins. A body mass index

(BMI) of 30kg/m2 or over, participation in another investigational study and a likelihood

of being unavailable for follow up.

Duratoin of study: 20 months, from February 2005 until October 2006

Interventions Coenzyme Q10 (CoQ10) 300mg/day (n=106)

versus

placebo (n=106)

Duration of treatment: 26 weeks or 6.5 weeks

Analysed n= 98, 8 withdrawals in treatment group, analysed n=96, 10 withdrawals in

the placebo group

Outcomes Primary outcomes: semen parameters and testicular volume

Secondary outcomes: adverse effects and hormone levels

Notes

Risk of bias



bias)

Low risk “Each eligible patient received a randomi-

sation number, which was determined by a

computer generated schedule. Therafter a

randomisation table was generated by the

method of random permuted blocks. Indi-

viduals who were geographically and oper-

ationally independent of the study investi-

gator performed the study randomisation”

Allocation concealment (selection bias) Unclear risk Allocation concealment: not mentioned


bias)

All outcomes

Low risk “The clinician prescriber and the patients

were blinded to the treatment condi-

tion. To maintain and guarantee blinding



Safarinejad 2009a (Continued)

CoQ10 and placebo were identical in ap-

pearance. Participant data collected dur-

ing this trial were kept confidential and

locked in a secure office area. Randomisa-

tion codes were opened only after all pa-

tients had completed the whole study pro-

tocol.”


All outcomes

Low risk All patients who dropped out of the trial

were accounted for - 8 from treatment

group and 10 from placebo group for rea-

sons such as withdrawal of consent, miss-

ing data and loss to follow up

Selective reporting (reporting bias) Unclear risk All semen, hormone and adverse effects

outcomes reported. Pregnancy outcome

not stated as an outcome initially but it was

reported on in the discussion

Other bias Unclear risk Funding source not stated. Can not defini-

tively assess other bias

Scott 1998

Methods Double blind randomised trial

Allocation concealment: no mention

Participants Country: Glasgow, UK

Population: Men attending subfertility clinic with low sperm motility

Mean age: 33.3 years±0.64

Recruited: N=69

Analysed: N=64

Inclusion criteria: Low sperm motility


Duration of study: 3 months and two weeks

Interventions Selenium 100µg/day (n=16)

versus

selenium 100µg + vitamin A 1mg + vitamin C 10mg + vitamin E 15mg/day (n=30)

versus

placebo (n=18)


Analysed = 64, 5 withdrew 1 from selenium group, 4 from selenium + vit A, C and E

group. All withdrawals were due to non-compliance

Outcomes Primary outcome: semen parameters

Secondary outcome: Pregnancy rates given although not stated as an initial outcome



Scott 1998 (Continued)

Notes Uneven numbers, multivitamin numbers are double the other groups

Need to ask author if they have separate numbers for pregnancy data. Currently have 5

pregnancies in the 2 treatment groups and none in placebo

Who was blinded, was the placebo identical when group 2 contained so many different

vitamins

Was there any allocation concealment?

Author has retired and is not contactable

Risk of bias



bias)

Unclear risk “As the patients entered the trial they were

randomly allocated to one of three treat-

ments, which had in turn been randomised

within each block of four numbers and

’blinded’ using a numeric code.”

Unclear as to why the uneven nature of the

numbers in the groups i.e. 30 in multivi-

tamin group and 16 in Selenium, 18 in

placebo



bias)

All outcomes

Low risk Double blind


All outcomes

Low risk Numbers of withdrawals and reasons (non

compliance) were reported

Selective reporting (reporting bias) Unclear risk Sperm counts and motility were reported

as per trial methods. Pregnancy rates were

given in the results of the trial, these had not

been specified in the methods. The preg-

nancy results given as a combination of the

2 vitamin groups. There were no pregnan-

cies in the placebo group




Sigman 2006

Methods Randomised double blind trial

Allocation concealment: adequate

Participants Country: Minneapolis, USA

Population: Males aged 18-65 years

IVF

Mean age: 36.2±5.8 (SD), 35.3±7.5 (SD)

Recruited: N=26

Analysed: N=21, 5 withdrawals

Inclusion criteria: Males 18-65 years with infertility of at least six months duration,

sperm concentration of at least five million sperm/mL, motility of 10%-50%, absent

pyospermia and normal FSH and testosterone levels.

Exclusion criteria: History of post pubertal mumps, cryptorchism, vasal or epididymal

surgery, history of medication or chemotherapy. recent alcohol, chronic marijuana. Use

of testosterone or steroids. Exposure to environmental toxins. Recent history of fever or

diabetes, liver failure, renal failure, endocrine disorder, untreated variocoele, urogenital

infection, or prior vasectomy reversal.


Interventions Carnitine (L-carnitine 2000mg +L-acetylcarnitine 1000mg/day) (n=12)

versus

placebo (n=9)

Outcomes Primary outcome: semen parameters

Secondary outcomes: Pregnancy - 2 pregnancies, 1 in the treatment arm after IVF and

one in placebo through intercourse

Notes Author replied 21.09.09 saying ’The published 2006 trial is the published version of

the 2003 abstract (Pryor 2003)’ and giving details of randomisation and concealment.

Author says he will try and find out about the 5 patients that dropped out.

Why did - ”5 additional patients entered the study but dropped out before completion“

- when did these patients enter and were they randomised? ”One of these 5 dropped out

because of pregnancy three months after starting carnitine“ Pryor paper excluded as it

is the same study as Sigman, author also gave details of randomisation and allocation

concealment, author will try to find info on 5 patients who dropped out.

Risk of bias



bias)

Low risk ”Patients were randomised to receive carni-

tine or placebo“

”The randomisation was done by a 3rd

party a company that oversaw the trial. We

sent the patient number of new recruited

patients in to them, they assigned them a

study number that was associated with a

collection of medication/placebo.“

The author replied to randomisation query



Sigman 2006 (Continued)

23.09.09 saying that the protocol stated

that - ”treatments will be assigned ran-

domly to a subject number. The numbers

will range from 1-84 for study centre 1 and

85-168 for study centre 2. Randomisation

of treatments for each centre will be done

independently. One half of subject num-

bers will be placebo, the other half, active

ingredient.“

Allocation concealment (selection bias) Low risk ”The investigators and study sites had the

study medication/placebo packets identi-

fied by number only. They were blinded to

what was in the medication/placebo pack-

ets. We were sent the code at the con-

clusion of the trial.“ The author replied

to a query on allocation concealment on

23.09.09 saying that the protocol stated

that - ” Integrated Data Solutions, Inc. will

keep the randomisation code in a separate

sealed envelope for each site until the end

of the study. The randomisation lists will

be provided to the packaging company for

packaging of the packets into patient med-

ication boxes.”


bias)

All outcomes

Low risk “Both the investigators and the patient were

blinded to the treatment arm assignment.”


All outcomes

Low risk “5 additional patients entered the study

but dropped out before completion. One

of these dropped out because of pregnancy

three months after starting carnitine.” Au-

thor replied to query re drop outs - “I have

data on one drop out at my site - the drop

out occurred after randomisation to carni-

tine. The drop out occurred before the first

follow-up study visit. The other four drop

outs were from the other study site - I am

trying to get that data for you” (23.09.09)

Selective reporting (reporting bias) Unclear risk Baseline data were similar

Pregnancy data were not an outcome but is

reported in the paper

All outcomes of interest were reported




Suleiman 1996

Methods Double blind randomised controlled trial


Participants Country: Saudi Arabia

Population: Men attending a fertility centre

Mean age: 34.8 (27-52 years), placebo 33.2 (22-45 years)

N=110

Inclusion criteria: Asthenospermic (>/=20 x 106/ml). sperm motility </= 40%, normal

sperm count, leucocyte concentration <5%, normal fructose concentration. Normal

female



Interventions Vitamin E 100mg 3x/day (n=52)

versus

placebo 3x/day (n=35)


Outcomes Primary outcome: motility and MDA concentration

Secondary outcome: live birth, pregnancy, miscarriage

Notes Method of randomisation not stated. Large imbalance between the treatment (n=52)

and placebo group (n=35) at analysis. Drop outs were accounted for in text.

Risk of bias



bias)

Unclear risk “ Either 100mg vitamin E or a placebo was

prescribed in a random double blind fash-

ion”. Method of randomisation not stated.

Large imbalance between the treatment (n=

52) and placebo group (n=35) at analysis



bias)

All outcomes

Low risk “Double blinded”. Does not report on who

was blinded


All outcomes

Unclear risk All men who dropped out the trial were ac-

counted for. Although the exact figures for

each group is unclear - “A total of 110 pa-

tients were enrolled in the study, but some

of the patients dropped out and some left

the region and failed to continue. When

the experiment was terminated, 52 patients

were found to have taken vitamin E and 35

patients to have taken the placebo.”



Suleiman 1996 (Continued)

Selective reporting (reporting bias) Unclear risk All outcomes stated in the methods were

reported in results

Other bias Unclear risk Unequal reporting bias “If the semen sam-

ple improved and the patient’s spouse be-

came pregnant, the treatment was stopped;

otherwise it was continued for 6 months.

The placebo was given for 6 months” Un-

equal reporting ?? incomplete outcome data

addressed

Tremellen 2007

Methods Randomised double blind controlled trial. randomisation by computer generated blocks.

Using a 2:1 ratio (treatment 2: placebo 1)

Allocation concealment: numbered bottles delivered to the site with all members of the

trial blinded to sequence, identical placebo


Participants Country: Australia

Population:male factor infertility undergoing IVF

Mean age: treatment group - 37.1±5.1, placebo group - 35.5±4.3

Recruited: N= 82

Randomised: N= 60

Inclusion criteria: men with sperm samples showing oxidative stress and a significant

level of DNA fragmentation (>25% Tunel positive)

Exclusion criteria: Female partner with diminished ovarian reserve or if the female partner

is aged over 39 years

Duration of study: 1.5 years

Interventions Menevit (folate 0.5mg, garlic 1000mg, lycopene 6mg, vitamin E 400 IU, vitamin C

100mg, zinc 25mg, selenium 26 µgm, palm oil). One capsule per day

versus

placebo (identical in appearance and taste - containing palm oil)

Duraton of treatment: 3 months prior to IVF cycle

Outcomes Primary outcome: embryo quality

Secondary outcomes: pregnancy, fertilization rate, side effects

Notes The study reports only on 37 men in the treatment group and not 38. There is no

explanation of the one man missing from this analysis.

Risk of bias




Tremellen 2007 (Continued)


bias)

Low risk “The randomisation schedule was com-

puter generated in blocks of six by Bayer

Consumer Care Australia”. Using a 2:1 ra-

tio

“There were no significant differences be-

tween the active and the placebo group

in terms of important baseline prognostic

characteristics...”

Allocation concealment (selection bias) Low risk “the appropriately numbered bottles of

capsules delivered to the clinical site with-

out any participant knowing the treatment

sequence. Patients were allocated the next

numerical treatment package (one to sixty

as they became eligible for enrolment”


bias)

All outcomes

Low risk “double blind placebo controlled trial”


All outcomes

Unclear risk All withdrawals were accounted for, 2 from

the intervention group, 4 from placebo all

due to the couples not going through to

embryo transfer

The study reports only on 37 men in the

treatment group and not 38 (page 219 ?

typo). There is no explanation of the one

man missing from this analysis Intention

to treat stated

Selective reporting (reporting bias) Low risk All specified outcomes are reported

Pregnancy only followed to 13 weeks


Wang 1983

Methods Randomised placebo controlled trial

Participants Country: Hong Kong

Population: New patients attending infertility clinic

Mean age: 33.7±4.4 years (28-45 years)

N=46

Inclusion criteria: Men with Idiopathic oligospermia attending fertility clinic with nor-

mal hormones. They had not received treatment with pharmacologic agents for 1 year

prior to entry into the trial. None of the female partners had irreversible causes of female

infertility




Wang 1983 (Continued)

Duration of study: 6-9 months

Interventions Pentoxifylline 400mg 3 x/day (n=11)

versus

placebo (n=7)


Other interventions not included in meta analysis were clomiphene citrate, mesterolone

and testosterone enanthate

Outcomes Primary outcome: Semen parameters and pregnancy

Notes Pentoxifylline supplied by Hoechst Aktiengesellshaft

Attempted to contact the author re motility data as it was stated in the paper that this

was an outcome. Also asked about control data for post treatment period and methods

of randomisation + allocation concealment. Author replied saying she no longer has the

data.

Risk of bias



bias)

Unclear risk “the subjects were randomly assigned to one of

the therapy groups..”

No mention of methods of randomisation



bias)

All outcomes

High risk No blinding - one of the interventions was an

intra muscular injection while the others were

oral


All outcomes

High risk Sperm motility data not given when motility was

discussed as an outcome of interest

Selective reporting (reporting bias) High risk No post-treatment control data given however

there is post-treatment given for treatment group

No intention to treat reported

Side effects reported in the results but this was

not stated as an initial outcome

Other bias Unclear risk Funding - Hoechst Aktiengesellshaft



Wong 2002

Methods Double blind randomised placebo controlled interventional study. Computer generated

randomisation

Allocation concealment: central pharmacy coding

Participants Country: Netherlands

Population: Fertile and subfertile men

Mean age: 34.3±3.9 years

Recruited: N=258 subfertile

Randomised: N=103

Inclusion criteria for subfertile group: failure to conceive after 1 year regular unprotected

intercourse and sperm concentration of 5 - 20 million/ml

Exclusion criteria for subfertile group: chromosomal disorders, cryptorchidism, vasec-

tomy, use of folic acid or zinc supplements in the previous 3 months, vitamin B defi-

ciency

Duration of study: 1 year

Interventions Folic acid 5mg/day (n=22)

versus

placebo (n=25)

Zinc sulphate 66 mg/day (n=23)

versus

placebo (n=25)

Zinc sulphate 66 mg/day + folic acid 5 mg/day (n=24)

versus

placebo (n=25)



Notes Data in median and range. Attempted to contact authors regarding means and standard

deviations. Letter returned to sender.

Risk of bias



bias)

Low risk “eligible fertile and subfertile men were

randomly assigned according to a simple

computer-generated randomisation sched-

ule in four blocks to receive folic acid

and placebo, zinc sulphate and placebo,

zinc sulphate and folic acid, or placebo

and placebo, which resulted in eight sub-

groups.” “At the end of the trial, the re-

search fellow received the randomisation

list that matched the codes from the hospi-

tal pharmacy.”



Wong 2002 (Continued)

Allocation concealment (selection bias) Unclear risk “capsules were coded by the hospital phar-

macy according to the randomisation list.”


bias)

All outcomes

Low risk Double blind

“Neither the research fellow and the par-

ticipants knew whether the participants re-

ceived folic acid, zinc sulphate or placebo

capsules”

“Folic acid and placebo capsules were yel-

low and identical in appearance. Zinc sul-

phate and placebo capsules were white and

identical in appearance”


All outcomes

Unclear risk 9 men withdrew from the subfertile arm of

the trial, 1 due to side effects (gastrointesti-

nal) and 8 due to lack of motivation. It is

unclear which treatment groups these men

were randomised to

Selective reporting (reporting bias) Low risk All outcomes except for semen volume is

given as medians

The protocol is given in methods section -

main outcomes are semen parameters and

these are presented in the report - “ Our

main goal was to investigate the effects of

the interventions on semen variables in fer-

tile and subfertile men.”


Zalata 1998

Methods A randomised pilot study

Allocation concealment not mentioned

Participants Country: Belgium

Population: Men attending andrology clinic

Mean age: Not given

N=22

Inclusion criteria: None given

Exclusion criteria: None given

Duration of study: ?4-6 months

Interventions Acetylcysteine 600mg/day (n=5)

versus

EFA (DHA 1g, y-linolenic acid, arachidonic acid 100mg) 100mg/day + antioxidant oil

mixture and tocopherol + B-carotene (n=12)

versus



Zalata 1998 (Continued)

Acetylcysteine + EFA + antioxidants (n=5)

Duration of treatment: 4-6 months


Notes Abstract only. No extractable data. Attempted to contact authors re availability of data

as means, if published?, methods of randomisation and allocation concealment.

Risk of bias



bias)

Unclear risk “A prospective randomised pilot study”

No details of randomisation given

Allocation concealment (selection bias) Unclear risk No details of allocation concealment


bias)

All outcomes



All outcomes


Selective reporting (reporting bias) Unclear risk Unclear, abstract only

Other bias Unclear risk Unclear

Zavaczki 2003

Methods Randomised placebo controlled clinical study

Allocation concealment not mentioned

Participants Country: Hungary

Population: Subfertile men attending andrology Department of Obstetrics and Gynae-

cology, University of Szeged

Mean age: Treatment group 29.6, placebo group 28.3 years

Recruited: N =26

Randomised: N=20

Inclusion criteria: Unsuccessful attempt at pregnancy for over one year. A healthy female

partner examined by a gynaecologist. Sperm volume < 2ml and/or sperm concentration

<20mill/ml and/or morphology ratio <30% and/or motility <50%. No genital tract

infection, no bacteria or fungi in urine or semen. Hormones are within physiological

range. Intact renal function. No excessive magnesium intake





Zavaczki 2003 (Continued)

Interventions Magnesium 3000mg/day (n=10)

versus

placebo (n=10)

Number analysed: N=14

Duration of treatment: 90 days


Secondary: pregnancy and side effects

Notes Attempted to contact authors regarding methods of randomisation and allocation con-

cealment

Risk of bias



bias)

Unclear risk “Patients were randomised and divided

into Magnesium or Placebo groups”

Methods of randomisation are not men-

tioned



bias)

All outcomes

Unclear risk “The members of Group P received the

same number of placebo tablets which

closely resembled the Magnerot tablets.”


All outcomes

Low risk 20 were randomised and 14 were analysed.

“To date 26 patients have participated in

the study and 20 men (10 in both groups)

have completed the program of treatment.

Six patients (2 in group M and 4 in group P

were excluded from the program, including

five cases for poor compliance, since they

did not attend the control meeting at the

end of treatment. One patient from Group

M experienced severe diarrhoea and so his

treatment was halted.”

Selective reporting (reporting bias) Unclear risk All data for outcomes in the trial were given,

unsure if these were prespecified

Other bias Unclear risk Funding - OKTA program. Tablets sup-

plied by pharmaceutical company



Characteristics of excluded studies [ordered by study ID]

Study Reason for exclusion

Cavallini 2004a Superceded by full paper of the trial - Cavallini 2004. Continuous data were used in Cavallini 2004 analysis.

Comhaire 2005 Used non randomised controls recruited from another unrelated trial.

Ebisch 2003 Inappropriate outcomes. Polymorphisms.

Ebisch 2006 This study is part of included study Wong 2002.

Elgindy 2008 Antioxidant given to the women and not to the men.

Micic 2001 Not randomised. 105 men in the treatment group and 35 in control. Abstract only.

Nikolova 2007 Trial is not randomised, allocation method is by alternation. Translated from Bulgarian by Ivan Sola. “50 of them

were randomly invited to participate depending on their order of attendance to the clinic”.

Pawlowicz 2001 Not a randomised controlled trial.

Pryor 2003 Conference proceeding superceded by Sigman 2006.

Rolf 1998 Conference proceeding superceded by Rolfe 1999.

Stanislavov 2009 Trial design is not random. The trial uses alternate allocation, odd and even numbers. Appears to be a report of

the trial Nikolova 2007.

Tremellen 2006 Conference proceeding superceded by Tremellen 2007.

Vicari 2001 Inapproriate control (anti-inflammatory). Treatment is not compared to placebo or another antioxidant.

Vicari 2001a Inappropriate comparison. The same antioxidant is compared at different times - L-carnitine +acetyl-carnitine

versus L-carnitine +acetyl-carnitine.

Zalata 1998a Same study as included trial Zalata 1998.

Characteristics of studies awaiting assessment [ordered by study ID]

Dimitriadis 2010


Participants 75 “infertile men with oligioasthenospermia”

Interventions Vardenafil (10mg/day)- Group A, sildenafil (50mg/day)- Group B, L-carnitine (1000mg/day)- Group C, no treat-

ment- Group D



Dimitriadis 2010 (Continued)

Outcomes sperm motility, sperm concentration

Notes

Wang 2010

Methods Random controlled trial

Participants 135 men with asthenozoospermia

Interventions L-carnitine + vitamin E vs vitamin E

Outcomes Pregnancy, adverse events, motile sperm.

Notes In Chinese - paper will need translation

Characteristics of ongoing studies [ordered by study ID]

Gonzalez 2009

Trial name or title Assessment of the efficacy of dietary supplement Spermotrend in the treatment of male infertility

Methods Randomised, double blind (subject, caregiver, investigator), placebo control, parallel assignment, efficacy

study

Participants Subfertile men

Interventions Spermotrend (vitamins plus other antioxidants) versus placebo

Outcomes Parameters of seminal analysis at weeks 24

Fertilisation achievement

Presence of mild or severe adverse effects

Starting date September 2009

Contact information Rogelio Gonzalez Sanchez, MD

53 7 838 2626 ext 277

Gynecologic and Obstetric Hospital

Havana, Cuba, 10400

Notes Havana, Cuba, 10400



Kumar 2010

Trial name or title Kumar R. Evaluation of oxidative stress as a cause for idiopathic male infertility and the role of Addyzoa in

its treatment

Methods Randomised, parallel group, placebo controlled trial. Method of generating randomisation sequence: Random

number table method of allocation concealment: Pre-numbered or coded identical containers. Blinding and

masking: participant, investigator,outcome assessor and data-entry operator/statistician blinded.

Participants Inclusion criteria: Infertile male, normal semen volume with either oligospermia (sperm density between 5

and 20 million/mL) or asthenospermia or teratospermia by WHO criteria

Exclusion criteria: Identifiable cause for semen abnormality (varicocele, cryptorchidism, orchitis, radiation,

chemotherapy, recent febrile illness, hormonal abnormality etc)

Interventions Intervention1: Addyzoa capsules: 2 BD for 3 months

Control Intervention1: placebo: 2 BD for 3 months

Outcomes Improvement in semen parameters timepoint: 3 months and 6 months

Pregnancy timepoint: Upto 12 months

Starting date 15-03-2009

Contact information Name: Dr Rajeev Kumar

Address: Department of Urology,AIIMS, Ansari Nagar 110029, New Delhi, India

Telephone: 01126594884

Email: [email protected]

Notes Main ID:CTRI/2009/091/000551. In WHO International Clinical trials Registry Platform.

Revel 2006

Trial name or title Revel A. A preliminary study on effect of omega-3 on human sperm. ClinicalTrials.gov. [ClinicalTrials.gov:

NCT00479960]

Methods Double blind randomised crossover trial

Participants Men with oligospermia, asthenoospermia or teratozoospermia

Interventions Omega 3 fatty acids

Outcomes Sperm count, sperm lipid transition determination

Starting date Enrollment due to be June 2007

Contact information Ariel Revel: [email protected]

Abraham Benchetrit: [email protected]

Notes Email sent to Drs Revel and Benchetrit 17.09.09 asking whether they have any data ready for their trial



Sadeghi 2008

Trial name or title Sadeghi M. Effects of coenzymeQ10 (CoQ10) supplementation on semen quality and seminal oxidative stress

of idiopathic oligoasthenoteratozoospermic (iOAT) infertile men. World Health Organization International

Clinical Trials Registry Platform Search Portal 2008. [ISRCTN: ISRCTN29954277]

Methods Randomised double blind placebo controlled trial

Participants Men with idiopathic oligoasthenoteratozoospermia with at least one year infertility

Interventions Coenzyme10 (Ubiquinone) 200mg 2x/day for 3 months

Outcomes Sperm morphology, motility and sperm DNA fragmentation

Starting date 1.10.08

Contact information [email protected]

Notes letter sent to author regarding data 17.09.09

Tsafrir 2010

Trial name or title Is a carnitine based food supplement (PorimoreTM) for infertile men superior to folate and zinc with regard

to pregnancy rates in intrauterine insemination cycles?

Methods Randomised, open label, active control, parallel assignment, efficacy study

Participants Infertile men aged 18-50 years

Interventions Carnitine supplement versus zinc and folate supplement

Outcomes Pregnancy rate and sperm quality parameters

Starting date February 2010 - expected completion December 2012

Contact information Avi Tsafrir, MD

tel: 972-6555111

[email protected]

Shaare-Zedek IVF and Infertility Unit

Jerusalem

91031

Notes



D A T A A N D A N A L Y S E S

Comparison 1. Antioxidant(s) versus control

Outcome or subgroup titleNo. of

studies

No. of

participants Statistical method Effect size

1 Live Birth per couple randomised 3 214 Peto Odds Ratio (Peto, Fixed, 95% CI) 4.85 [1.92, 12.24]

1.1 Vitamin E versus placebo 2 117 Peto Odds Ratio (Peto, Fixed, 95% CI) 6.44 [1.72, 24.04]

1.2 Zinc versus no treatment 1 97 Peto Odds Ratio (Peto, Fixed, 95% CI) 3.67 [1.00, 13.51]

2 Pregnancy rate per couple

randomised

15 964 Peto Odds Ratio (Peto, Fixed, 95% CI) 4.18 [2.65, 6.59]

2.1 Combined antioxidants

versus placebo/no treatment


2.2 L acetyl carnitine versus

placebo


2.3 L carnitine versus placebo 3 136 Peto Odds Ratio (Peto, Fixed, 95% CI) 5.08 [1.51, 17.09]

2.4 L acetyl carnitine + L

carnitine versus placebo


2.5 Coenzyme Q10 versus

placebo


2.6 Pentoxifylline versus

placebo


2.7 Magnesium versus placebo 1 20 Peto Odds Ratio (Peto, Fixed, 95% CI) 7.39 [0.15, 372.38]


2.9 Vitamin C plus Vitamin E

versus placebo



3 Adverse event: Miscarriage rate

per couple randomised



versus placebo




4 DNA fragmentation 1 Mean Difference (IV, Fixed, 95% CI) Subtotals only

4.1 Vitamin C + vitamin E

versus placebo at 2 months

1 64 Mean Difference (IV, Fixed, 95% CI) -13.80 [-17.50, -

10.10]

5 Sperm total motility at 3 months

or less

10 Mean Difference (IV, Random, 95% CI) Subtotals only

5.1 Docosahexaenoic acid

(DHA) 400g/day versus

placebo

1 14 Mean Difference (IV, Random, 95% CI) -7.80 [-30.56,

14.96]


(DHA) 800mg/day vs placebo


3.91]

5.3 Ascorbic acid (Vitamin C)

200mg/day versus placebo

1 15 Mean Difference (IV, Random, 95% CI) 2.0 [-24.07, 28.07]

5.4 Ascorbic acid (Vitamin

C)1000mg/day versus placebo

1 15 Mean Difference (IV, Random, 95% CI) 45.0 [15.25, 74.75]



5.5 Ascorbic acid (vitamin C)

+ Vitamin E versus placebo at 2

months


5.6 L-carnitine +l-acetyl

carnitine versus placebo at 3

months

1 21 Mean Difference (IV, Random, 95% CI) -9.0 [-39.49, 21.49]

5.7 Selenium versus placebo

at 3 months





5.9 N-acetylcysteine versus

placebo at 3 months


5.10 Magnesium versus

placebo at 90 days


5.11 L-carnitine versus

placebo


5.12 Pentoxifyllin versus no

treatment at 3 months


5.13 Zinc versus no treatment

at 3 months


5.14 Zinc + Vitamin E versus

no treatment at 3 months


5.15 Zinc + Vitamin E +

Vitamin C versus no treatment

at 3 months


6 Sperm total motility at 6 months 7 Mean Difference (IV, Random, 95% CI) Subtotals only

6.1 L-carnitine versus placebo

at 6 months


6.2 L-acetyl carnitine versus

placebo at 6 months


6.3 L-carnitine + L-acetyl


months



at 26 weeks (6 months)


6.5 N-acetyl-cysteine versus

placebo at 26 weeks (6months)


6.6 Selenium plus

N-acetyl-cysteine versus




placebo at 6 months.

Safarinejad trial =26 weeks


6.8 Vitamin E versus placebo

at 6 months



or more



at 9 months



placebo at 9 months






months



placebo at 9 months


8 Sperm concentration at 3

months or less




placebo


30.49]



placebo


8.3 Magnesium versus placebo

at 90 days


8.4 Vitamin C + Vitamin E



8.5 N-acetylcysteine versus

placebo at 3 months



placebo at 3 months


8.7 L-carnitine versus placebo 1 30 Mean Difference (IV, Random, 95% CI) 29.5 [25.39, 33.61]


months



at 6 months



placebo at 6 months




months



at 26 weeks (6 months)


9.5 N-acetyl-cysteine versus



9.6 Selenium plus

N-acetyl-cysteine versus




placebo at 6 months



placebo up to 6 months



months or more

3 332 Mean Difference (IV, Fixed, 95% CI) 1.61 [0.61, 2.61]


placebo at 9 months

1 20 Mean Difference (IV, Fixed, 95% CI) 9.27 [-1.51, 20.05]


placebo at 9 months




months





placebo at 9 months or more


11 Total sperm motility over time 16 Mean Difference (IV, Random, 95% CI) Subtotals only

11.1 Total sperm motility at 3

months or less



months



months or more


12 Sperm concentration over time 12 Mean Difference (IV, Random, 95% CI) Subtotals only

12.1 Sperm concentration at

3 months or less


12.2 Sperm concentration 6

months


12.3 Sperm concentration at

9 months or more


13 Side effects 6 Peto Odds Ratio (Peto, Fixed, 95% CI) Subtotals only

13.1 gastrointestinal 6 426 Peto Odds Ratio (Peto, Fixed, 95% CI) 1.63 [0.48, 5.58]

13.2 euphoria 1 86 Peto Odds Ratio (Peto, Fixed, 95% CI) 1.21 [0.16, 9.01]

14 Sperm motility at 3 months or

less

Other data No numeric data

14.1 L-carnitine +

Acetyl-carnitine versus placebo

(median and interquartile

range)



versus no treatment


14.3 Vitamin E versus placebo Other data No numeric data


placebo



Placebo


15 Sperm motility at 6 months Other data No numeric data

15.1 L-carnitine +



range)



placebo


15.3 Folic acid versus placebo Other data No numeric data

15.4 Zinc versus placebo Other data No numeric data

15.5 Zinc + folic acid versus

placebo



months or less


16.1 L-carnitine +



range)


16.2 Vitamin E versus placebo Other data No numeric data




placebo



months


17.1 L-carnitine +

acetyl-carnitine versus placebo


17.2 Folic acid versus Placebo Other data No numeric data

17.3 Zinc versus Placebo Other data No numeric data

18 Pregnancy 15 963 Peto Odds Ratio (Peto, Fixed, 95% CI) 4.40 [2.78, 6.97]

18.1 Pregnancy rate of trials

that also report live birth


18.2 Pregnancy rate only

reported


Comparison 2. Live birth versus pregnancy


studies

No. of


1 Live birth 2 Peto Odds Ratio (Peto, Fixed, 95% CI) Subtotals only

1.1 live birth 2 184 Peto Odds Ratio (Peto, Fixed, 95% CI) 4.73 [1.82, 12.27]

1.2 pregnancy 2 184 Peto Odds Ratio (Peto, Fixed, 95% CI) 5.53 [2.34, 13.08]

Comparison 3. Head to head antioxidant(s)


studies

No. of


1 Pregnancy per couple

randomised

2 Peto Odds Ratio (Peto, Fixed, 95% CI) Subtotals only

1.1 L acetyl carnitine +

L carnitine versus L acetyl

carnitine



carnitine versus L- carnitine



carnitine versus Vitamin E +

Vitamin C



or less

7 Mean Difference (IV, Fixed, 95% CI) Subtotals only

2.1 Ethylcysteine 600mg/day

vs Vitamin E

1 10 Mean Difference (IV, Fixed, 95% CI) -1.90 [-41.97,

38.17]

2.2 Docosahexaenoic

acid (DHA) 400g/day

vs Docosahexaenoic acid

800mg/day




2.3 Ascorbic Acid 200mg/day

versus Ascorbic Acid

1000mg/day

1 20 Mean Difference (IV, Fixed, 95% CI) -43.0 [-67.10, -

18.90]

2.4 Vitamin E + Selenium

versus Vitamin B at 3 months


2.5 Zinc versus Zinc +

Vitamin E at 3 months

1 18 Mean Difference (IV, Fixed, 95% CI) -1.0 [-13.00, 13.00]

2.6 Zinc versus Zinc +

Vitamin E + Vitamin C at 3

months


2.7 Zinc + Vitamin E versus

Zinc + Vitamin E + Vitamin C

at 3 months


2.8 Selenium versus combined

antioxidants




Vitamin C


3 Sperm total motility at 6 months 2 Mean Difference (IV, Fixed, 95% CI) Subtotals only

3.1 L-aceytl carnitine

+L-carnitine versus L-carnitine

at 6 months


3.2 L-acetyl carnitine +

L-carnitine versus L-acetyl

carnitine at 6 months


3.3 Selenium versus

N-acetyl-cysteine at 26 weeks

(6 months)


3.4 Selenium versus selenium

plus N-acetyl-cysteine at 26

weeks (6 months)

1 116 Mean Difference (IV, Fixed, 95% CI) -3.10 [-4.16, -2.04]

3.5 N-acetyl-cysteine vs

selenium plus N-acetyl-cysteine

at 26 weeks



or more




at 9 months







months or less


5.1 Ethylcysteine 600mg/day

vs Vitamin E




Docosahexaenoic acid (DHA)

800g/day


28.27]



5.3 L-carnitine versus Vitamin

E + Vitamin C



months




at 6 months






13.06]

6.3 Selenium versus

N-acetyl-cysteine at 26 weeks

(6 months)


6.4 Selenium versus selenium

plus N-acetyl-cysteine at 26

weeks (6 months)


6.5 N-acetyl-cysteine vs

selenium plus N-acetyl-cysteine

at 26 weeks



months or more




at 9 months






8 Side effects 1 150 Odds Ratio (M-H, Fixed, 95% CI) 0.0 [0.0, 0.0]



Vitamin C

1 150 Odds Ratio (M-H, Fixed, 95% CI) 0.0 [0.0, 0.0]


months


9.1 Zinc versus Folic acid Other data No numeric data

9.2 Zinc versus Zinc + Folic

acid


10 Sperm motility at 6 months Other data No numeric data

10.1 Zinc versus Folic acid Other data No numeric data



Analysis 1.1. Comparison 1 Antioxidant(s) versus control, Outcome 1 Live Birth per couple randomised.

Review: Antioxidants for male subfertility

Comparison: 1 Antioxidant(s) versus control

Outcome: 1 Live Birth per couple randomised

Study or subgroup Experimental Control Peto Odds Ratio Weight Peto Odds Ratio

n/N n/N Peto,Fixed,95% CI Peto,Fixed,95% CI

1 Vitamin E versus placebo

Kessopoulou 1995 1/15 0/15 5.6 % 7.39 [ 0.15, 372.38 ]

Suleiman 1996 9/52 0/35 43.8 % 6.33 [ 1.56, 25.63 ]

Subtotal (95% CI) 67 50 49.4 % 6.44 [ 1.72, 24.04 ]

Total events: 10 (Experimental), 0 (Control)

Heterogeneity: Chi2 = 0.01, df = 1 (P = 0.94); I2 =0.0%

Test for overall effect: Z = 2.77 (P = 0.0056)

2 Zinc versus no treatment

Omu 1998 8/49 2/48 50.6 % 3.67 [ 1.00, 13.51 ]

Subtotal (95% CI) 49 48 50.6 % 3.67 [ 1.00, 13.51 ]


Heterogeneity: not applicable


Total (95% CI) 116 98 100.0 % 4.85 [ 1.92, 12.24 ]




Test for subgroup differences: Chi2 = 0.35, df = 1 (P = 0.55), I2 =0.0%

0.001 0.01 0.1 1 10 100 1000

Favours control Favours antioxidant



Analysis 1.2. Comparison 1 Antioxidant(s) versus control, Outcome 2 Pregnancy rate per couple

randomised.



Outcome: 2 Pregnancy rate per couple randomised

Study or subgroup Experimental Control Peto Odds Ratio Peto Odds Ratio


1 Combined antioxidants versus placebo/no treatment

Galatioto 2008 1/20 0/22 8.17 [ 0.16, 413.39 ]

Tremellen 2007 20/38 4/20 3.75 [ 1.26, 11.16 ]

Subtotal (95% CI) 58 42 3.97 [ 1.39, 11.33 ]




2 L acetyl carnitine versus placebo

Balercia 2005 2/15 1/5 0.61 [ 0.04, 9.64 ]

Subtotal (95% CI) 15 5 0.61 [ 0.04, 9.64 ]




3 L carnitine versus placebo

Balercia 2005 2/15 1/5 0.61 [ 0.04, 9.64 ]

Lenzi 2003 6/43 0/43 8.37 [ 1.61, 43.58 ]

Peivandi 2010 3/15 0/15 8.57 [ 0.82, 89.45 ]

Subtotal (95% CI) 73 63 5.08 [ 1.51, 17.09 ]


Heterogeneity: Chi2 = 2.81, df = 2 (P = 0.25); I2 =29%


4 L acetyl carnitine + L carnitine versus placebo

Balercia 2005 5/15 1/5 1.83 [ 0.21, 15.73 ]

Cavallini 2004 9/39 1/47 7.50 [ 2.01, 27.98 ]

Lenzi 2004 4/30 0/26 7.20 [ 0.95, 54.34 ]

Sigman 2006 1/12 1/9 0.74 [ 0.04, 13.02 ]

Subtotal (95% CI) 96 87 4.48 [ 1.77, 11.36 ]




5 Coenzyme Q10 versus placebo

0.002 0.1 1 10 500


(Continued . . . )



(. . . Continued)Study or subgroup Experimental Control Peto Odds Ratio Peto Odds Ratio


Balercia 2009 6/30 3/30 2.16 [ 0.53, 8.82 ]

Safarinejad 2009a 0/106 0/106 0.0 [ 0.0, 0.0 ]

Subtotal (95% CI) 136 136 2.16 [ 0.53, 8.82 ]




6 Pentoxifylline versus placebo

Wang 1983 0/11 0/7 0.0 [ 0.0, 0.0 ]

Subtotal (95% CI) 11 7 0.0 [ 0.0, 0.0 ]



Test for overall effect: Z = 0.0 (P < 0.00001)

7 Magnesium versus placebo

Zavaczki 2003 1/10 0/10 7.39 [ 0.15, 372.38 ]

Subtotal (95% CI) 10 10 7.39 [ 0.15, 372.38 ]





Suleiman 1996 11/52 0/35 6.64 [ 1.84, 23.93 ]

Subtotal (95% CI) 52 35 6.64 [ 1.84, 23.93 ]




9 Vitamin C plus Vitamin E versus placebo

Rolf 1999 0/15 0/16 0.0 [ 0.0, 0.0 ]

Subtotal (95% CI) 15 16 0.0 [ 0.0, 0.0 ]





Omu 1998 11/49 2/48 4.75 [ 1.49, 15.20 ]

Subtotal (95% CI) 49 48 4.75 [ 1.49, 15.20 ]




Total (95% CI) 515 449 4.18 [ 2.65, 6.59 ]





0.002 0.1 1 10 500




Analysis 1.3. Comparison 1 Antioxidant(s) versus control, Outcome 3 Adverse event: Miscarriage rate per

couple randomised.



Outcome: 3 Adverse event: Miscarriage rate per couple randomised



1 Combined antioxidants versus placebo

Tremellen 2007 2/38 2/20 54.1 % 0.48 [ 0.06, 4.03 ]

Subtotal (95% CI) 38 20 54.1 % 0.48 [ 0.06, 4.03 ]





Suleiman 1996 2/52 0/35 30.1 % 5.43 [ 0.32, 93.28 ]

Subtotal (95% CI) 52 35 30.1 % 5.43 [ 0.32, 93.28 ]





Omu 1998 1/49 0/48 15.8 % 7.24 [ 0.14, 364.94 ]

Subtotal (95% CI) 49 48 15.8 % 7.24 [ 0.14, 364.94 ]




Total (95% CI) 139 103 100.0 % 1.54 [ 0.32, 7.30 ]




Test for subgroup differences: Chi2 = 2.50, df = 2 (P = 0.29), I2 =20%

0.01 0.1 1 10 100

Favours antioxidant Favours control



Analysis 1.4. Comparison 1 Antioxidant(s) versus control, Outcome 4 DNA fragmentation.



Outcome: 4 DNA fragmentation

Study or subgroup Experimental Control Mean Difference Weight Mean Difference

N Mean(SD) N Mean(SD) IV,Fixed,95% CI IV,Fixed,95% CI

1 Vitamin C + vitamin E versus placebo at 2 months

Greco 2005 32 9.1 (7.2) 32 22.9 (7.9) 100.0 % -13.80 [ -17.50, -10.10 ]

-50 -25 0 25 50


Analysis 1.5. Comparison 1 Antioxidant(s) versus control, Outcome 5 Sperm total motility at 3 months or

less.



Outcome: 5 Sperm total motility at 3 months or less


N Mean(SD) N Mean(SD) IV,Random,95% CI IV,Random,95% CI

1 Docosahexaenoic acid (DHA) 400g/day versus placebo

Conquer 2000 9 39.4 (24.3) 5 47.2 (18.6) 100.0 % -7.80 [ -30.56, 14.96 ]

Subtotal (95% CI) 9 5 100.0 % -7.80 [ -30.56, 14.96 ]



2 Docosahexaenoic acid (DHA) 800mg/day vs placebo

Conquer 2000 10 32 (16.1) 5 47.2 (18.6) 100.0 % -15.20 [ -34.31, 3.91 ]

Subtotal (95% CI) 10 5 100.0 % -15.20 [ -34.31, 3.91 ]



3 Ascorbic acid (Vitamin C) 200mg/day versus placebo

Dawson 1990 10 51 (22.1) 5 49 (25.3) 100.0 % 2.00 [ -24.07, 28.07 ]

Subtotal (95% CI) 10 5 100.0 % 2.00 [ -24.07, 28.07 ]


-50 -25 0 25 50


(Continued . . . )



(. . . Continued)Study or subgroup Experimental Control Mean Difference Weight Mean Difference



4 Ascorbic acid (Vitamin C)1000mg/day versus placebo

Dawson 1990 10 94 (32) 5 49 (25.3) 100.0 % 45.00 [ 15.25, 74.75 ]

Subtotal (95% CI) 10 5 100.0 % 45.00 [ 15.25, 74.75 ]



5 Ascorbic acid (vitamin C) + Vitamin E versus placebo at 2 months

Greco 2005 32 41.6 (22) 32 38.7 (21.5) 100.0 % 2.90 [ -7.76, 13.56 ]

Subtotal (95% CI) 32 32 100.0 % 2.90 [ -7.76, 13.56 ]



6 L-carnitine +l-acetyl carnitine versus placebo at 3 months

Sigman 2006 12 28.6 (38.1) 9 37.6 (33) 100.0 % -9.00 [ -39.49, 21.49 ]

Subtotal (95% CI) 12 9 100.0 % -9.00 [ -39.49, 21.49 ]



7 Selenium versus placebo at 3 months

Scott 1998 16 30.2 (22.8) 9 15.3 (17.4) 100.0 % 14.90 [ -1.04, 30.84 ]

Subtotal (95% CI) 16 9 100.0 % 14.90 [ -1.04, 30.84 ]



8 Combined antioxidants versus placebo at 3 months

Scott 1998 30 27 (20.3) 9 15.3 (17.4) 100.0 % 11.70 [ -1.79, 25.19 ]

Subtotal (95% CI) 30 9 100.0 % 11.70 [ -1.79, 25.19 ]



9 N-acetylcysteine versus placebo at 3 months

Ciftci 2009 60 31.29 (8.62) 60 20.33 (8.43) 100.0 % 10.96 [ 7.91, 14.01 ]

Subtotal (95% CI) 60 60 100.0 % 10.96 [ 7.91, 14.01 ]



10 Magnesium versus placebo at 90 days

Zavaczki 2003 10 33.5 (29.8) 10 19 (14.4) 100.0 % 14.50 [ -6.01, 35.01 ]

Subtotal (95% CI) 10 10 100.0 % 14.50 [ -6.01, 35.01 ]



11 L-carnitine versus placebo

Peivandi 2010 15 48.3 (0.16) 15 17 (0.09) 100.0 % 31.30 [ 31.21, 31.39 ]

Subtotal (95% CI) 15 15 100.0 % 31.30 [ 31.21, 31.39 ]


-50 -25 0 25 50


(Continued . . . )






12 Pentoxifyllin versus no treatment at 3 months

Micic 1988 51 31.21 (10.66) 39 18.44 (6.35) 100.0 % 12.77 [ 9.23, 16.31 ]

Subtotal (95% CI) 51 39 100.0 % 12.77 [ 9.23, 16.31 ]



13 Zinc versus no treatment at 3 months

Omu 2008 11 49 (12) 3 24 (12) 100.0 % 25.00 [ 9.68, 40.32 ]

Subtotal (95% CI) 11 3 100.0 % 25.00 [ 9.68, 40.32 ]



14 Zinc + Vitamin E versus no treatment at 3 months

Omu 2008 12 50 (18) 3 24 (12) 100.0 % 26.00 [ 9.03, 42.97 ]

Subtotal (95% CI) 12 3 100.0 % 26.00 [ 9.03, 42.97 ]



15 Zinc + Vitamin E + Vitamin C versus no treatment at 3 months

Omu 2008 14 50 (20) 3 24 (12) 100.0 % 26.00 [ 8.85, 43.15 ]

Subtotal (95% CI) 14 3 100.0 % 26.00 [ 8.85, 43.15 ]



-50 -25 0 25 50




Analysis 1.6. Comparison 1 Antioxidant(s) versus control, Outcome 6 Sperm total motility at 6 months.



Outcome: 6 Sperm total motility at 6 months



1 L-carnitine versus placebo at 6 months

Balercia 2005 15 64.53 (8.41) 5 43.4 (9.85) 100.0 % 21.13 [ 11.50, 30.76 ]

Subtotal (95% CI) 15 5 100.0 % 21.13 [ 11.50, 30.76 ]



2 L-acetyl carnitine versus placebo at 6 months

Balercia 2005 15 60.43 (10.46) 5 43.4 (9.85) 100.0 % 17.03 [ 6.90, 27.16 ]

Subtotal (95% CI) 15 5 100.0 % 17.03 [ 6.90, 27.16 ]



3 L-carnitine + L-acetyl carnitine versus placebo at 6 months

Balercia 2005 15 61.07 (9.07) 5 43.4 (9.85) 38.4 % 17.67 [ 7.89, 27.45 ]

Lenzi 2004 30 31.11 (13.46) 26 29.55 (9.5) 43.9 % 1.56 [ -4.48, 7.60 ]

Sigman 2006 12 32.3 (24.2) 9 40 (33) 17.7 % -7.70 [ -33.24, 17.84 ]

Subtotal (95% CI) 57 40 100.0 % 6.12 [ -7.37, 19.60 ]

Heterogeneity: Tau2 = 98.36; Chi2 = 8.61, df = 2 (P = 0.01); I2 =77%


4 Selenium versus placebo at 26 weeks (6 months)

Safarinejad 2009 116 26.1 (2.9) 39 22.9 (2.2) 100.0 % 3.20 [ 2.33, 4.07 ]

Subtotal (95% CI) 116 39 100.0 % 3.20 [ 2.33, 4.07 ]



5 N-acetyl-cysteine versus placebo at 26 weeks (6months)

Safarinejad 2009 118 24.8 (2.9) 39 22.9 (2.2) 100.0 % 1.90 [ 1.03, 2.77 ]

Subtotal (95% CI) 118 39 100.0 % 1.90 [ 1.03, 2.77 ]



6 Selenium plus N-acetyl-cysteine versus placebo at 26 weeks (6months)

Safarinejad 2009 116 29.2 (2.9) 39 22.9 (2.2) 100.0 % 6.30 [ 5.43, 7.17 ]

Subtotal (95% CI) 116 39 100.0 % 6.30 [ 5.43, 7.17 ]



7 Coenzyme Q10 versus placebo at 6 months. Safarinejad trial =26 weeks

-20 -10 0 10 20


(Continued . . . )





Balercia 2009 30 39.41 (6.8) 30 34.93 (8.04) 2.3 % 4.48 [ 0.71, 8.25 ]

Safarinejad 2009a 106 27.6 (2.2) 106 23.1 (2.1) 97.7 % 4.50 [ 3.92, 5.08 ]

Subtotal (95% CI) 136 136 100.0 % 4.50 [ 3.93, 5.07 ]

Heterogeneity: Tau2 = 0.0; Chi2 = 0.00, df = 1 (P = 0.99); I2 =0.0%


8 Vitamin E versus placebo at 6 months

Suleiman 1996 52 48.9 (15.5) 35 35.9 (12.8) 100.0 % 13.00 [ 7.02, 18.98 ]

Subtotal (95% CI) 52 35 100.0 % 13.00 [ 7.02, 18.98 ]



-20 -10 0 10 20


Analysis 1.7. Comparison 1 Antioxidant(s) versus control, Outcome 7 Sperm total motility at 9 months or

more.



Outcome: 7 Sperm total motility at 9 months or more




Balercia 2005 15 54.27 (8.96) 5 42.73 (10.02) 100.0 % 11.54 [ 1.66, 21.42 ]

Subtotal (95% CI) 15 5 100.0 % 11.54 [ 1.66, 21.42 ]




Balercia 2005 15 50.57 (5.71) 5 42.73 (10.02) 100.0 % 7.84 [ -1.41, 17.09 ]

Subtotal (95% CI) 15 5 100.0 % 7.84 [ -1.41, 17.09 ]




Balercia 2005 15 49 (7.8) 5 42.73 (10.02) 100.0 % 6.27 [ -3.36, 15.90 ]

-20 -10 0 10 20


(Continued . . . )





Subtotal (95% CI) 15 5 100.0 % 6.27 [ -3.36, 15.90 ]



4 Coenzyme Q10 versus placebo at 9 months

Balercia 2009 30 32.93 (6.33) 30 35.3 (8) 38.1 % -2.37 [ -6.02, 1.28 ]

Safarinejad 2009a 106 24.2 (2.1) 106 22.8 (2.2) 61.9 % 1.40 [ 0.82, 1.98 ]

Subtotal (95% CI) 136 136 100.0 % -0.04 [ -3.62, 3.55 ]



-20 -10 0 10 20


Analysis 1.8. Comparison 1 Antioxidant(s) versus control, Outcome 8 Sperm concentration at 3 months or

less.



Outcome: 8 Sperm concentration at 3 months or less




Conquer 2000 9 37.8 (36.9) 9 43.1 (40.5) 6.2 % -5.30 [ -41.09, 30.49 ]

Subtotal (95% CI) 9 9 6.2 % -5.30 [ -41.09, 30.49 ]




Conquer 2000 10 44.6 (41.1) 9 43.1 (40.5) 6.0 % 1.50 [ -35.23, 38.23 ]

Subtotal (95% CI) 10 9 6.0 % 1.50 [ -35.23, 38.23 ]



3 Magnesium versus placebo at 90 days

Zavaczki 2003 10 16.1 (10.2) 10 10.9 (7.4) 14.7 % 5.20 [ -2.61, 13.01 ]

Subtotal (95% CI) 10 10 14.7 % 5.20 [ -2.61, 13.01 ]

-50 -25 0 25 50


(Continued . . . )







4 Vitamin C + Vitamin E versus placebo at 2 months

Greco 2005 32 27.5 (24.6) 32 20.3 (21.2) 13.7 % 7.20 [ -4.05, 18.45 ]

Rolf 1999 15 20.6 (13.5) 16 25 (17.8) 13.7 % -4.40 [ -15.48, 6.68 ]

Subtotal (95% CI) 47 48 27.4 % 1.36 [ -10.01, 12.72 ]



5 N-acetylcysteine versus placebo at 3 months

Ciftci 2009 60 21.85 (11.08) 60 22.32 (22) 15.0 % -0.47 [ -6.70, 5.76 ]

Subtotal (95% CI) 60 60 15.0 % -0.47 [ -6.70, 5.76 ]



6 Pentoxifylline versus placebo at 3 months

Wang 1983 11 12.8 (4.7) 7 8.5 (5.6) 15.3 % 4.30 [ -0.69, 9.29 ]

Subtotal (95% CI) 11 7 15.3 % 4.30 [ -0.69, 9.29 ]



7 L-carnitine versus placebo

Peivandi 2010 15 46 (3.62) 15 16.5 (7.26) 15.4 % 29.50 [ 25.39, 33.61 ]

Subtotal (95% CI) 15 15 15.4 % 29.50 [ 25.39, 33.61 ]



Total (95% CI) 162 158 100.0 % 6.04 [ -5.42, 17.50 ]

Heterogeneity: Tau2 = 217.11; Chi2 = 107.29, df = 7 (P<0.00001); I2 =93%



-50 -25 0 25 50




Analysis 1.9. Comparison 1 Antioxidant(s) versus control, Outcome 9 Sperm concentration at 6 months.



Outcome: 9 Sperm concentration at 6 months




Balercia 2005 15 45.53 (21.42) 5 33.73 (14.36) 100.0 % 11.80 [ -4.81, 28.41 ]

Subtotal (95% CI) 15 5 100.0 % 11.80 [ -4.81, 28.41 ]




Balercia 2005 15 39.57 (19.99) 5 33.73 (14.36) 100.0 % 5.84 [ -10.31, 21.99 ]

Subtotal (95% CI) 15 5 100.0 % 5.84 [ -10.31, 21.99 ]




Balercia 2005 15 37.4 (16.42) 5 33.73 (14.36) 18.9 % 3.67 [ -11.41, 18.75 ]

Lenzi 2004 30 22.09 (9.05) 26 22.17 (16.95) 81.1 % -0.08 [ -7.36, 7.20 ]

Subtotal (95% CI) 45 31 100.0 % 0.63 [ -5.93, 7.18 ]



4 Selenium versus placebo at 26 weeks (6 months)

Safarinejad 2009 116 27.6 (6.4) 39 23.5 (5.8) 100.0 % 4.10 [ 1.94, 6.26 ]

Subtotal (95% CI) 116 39 100.0 % 4.10 [ 1.94, 6.26 ]



5 N-acetyl-cysteine versus placebo at 26 weeks (6months)

Safarinejad 2009 118 26.8 (5.3) 39 23.5 (5.8) 100.0 % 3.30 [ 1.24, 5.36 ]

Subtotal (95% CI) 118 39 100.0 % 3.30 [ 1.24, 5.36 ]



6 Selenium plus N-acetyl-cysteine versus placebo at 26 weeks (6months)

Safarinejad 2009 116 32.1 (6.8) 39 23.5 (5.8) 100.0 % 8.60 [ 6.40, 10.80 ]

Subtotal (95% CI) 116 39 100.0 % 8.60 [ 6.40, 10.80 ]



7 Coenzyme Q10 versus placebo at 6 months

Balercia 2009 30 44.93 (19.3) 30 46.37 (19.77) 24.7 % -1.44 [ -11.33, 8.45 ]

-20 -10 0 10 20


(Continued . . . )





Safarinejad 2009a 106 26.4 (4.4) 106 20.8 (4.3) 75.3 % 5.60 [ 4.43, 6.77 ]

Subtotal (95% CI) 136 136 100.0 % 3.86 [ -2.09, 9.81 ]



8 Pentoxifylline versus placebo up to 6 months

Wang 1983 11 11.1 (5.8) 7 8.3 (5.6) 100.0 % 2.80 [ -2.58, 8.18 ]

Subtotal (95% CI) 11 7 100.0 % 2.80 [ -2.58, 8.18 ]



-20 -10 0 10 20


Analysis 1.10. Comparison 1 Antioxidant(s) versus control, Outcome 10 Sperm concentration at 9 months

or more.



Outcome: 10 Sperm concentration at 9 months or more




Balercia 2005 15 39.4 (13.93) 5 30.13 (9.3) 0.9 % 9.27 [ -1.51, 20.05 ]

Subtotal (95% CI) 15 5 0.9 % 9.27 [ -1.51, 20.05 ]




Balercia 2005 15 31.21 (8.6) 5 30.13 (9.3) 1.2 % 1.08 [ -8.16, 10.32 ]

Subtotal (95% CI) 15 5 1.2 % 1.08 [ -8.16, 10.32 ]




Balercia 2005 15 33.27 (13.62) 5 30.13 (9.3) 0.9 % 3.14 [ -7.54, 13.82 ]

Subtotal (95% CI) 15 5 0.9 % 3.14 [ -7.54, 13.82 ]

-20 -10 0 10 20


(Continued . . . )







4 Coenzyme Q10 versus placebo at 9 months or more

Balercia 2009 30 44.18 (20.43) 30 49.56 (20.47) 0.9 % -5.38 [ -15.73, 4.97 ]

Safarinejad 2009a 106 22.8 (3.8) 106 21.2 (3.8) 96.1 % 1.60 [ 0.58, 2.62 ]

Subtotal (95% CI) 136 136 97.1 % 1.53 [ 0.51, 2.55 ]



Total (95% CI) 181 151 100.0 % 1.61 [ 0.61, 2.61 ]




-20 -10 0 10 20


Analysis 1.11. Comparison 1 Antioxidant(s) versus control, Outcome 11 Total sperm motility over time.



Outcome: 11 Total sperm motility over time



1 Total sperm motility at 3 months or less

Ciftci 2009 60 31.29 (8.62) 60 20.33 (8.43) 12.4 % 10.96 [ 7.91, 14.01 ]

Conquer 2000 10 32 (16.1) 9 47.2 (18.6) 9.6 % -15.20 [ -30.92, 0.52 ]

Dawson 1990 10 94 (32) 10 49 (25.3) 7.0 % 45.00 [ 19.72, 70.28 ]

Greco 2005 32 41.6 (22) 32 38.7 (21.5) 11.0 % 2.90 [ -7.76, 13.56 ]

Micic 1988 51 31.21 (10.66) 39 18.44 (6.35) 12.3 % 12.77 [ 9.23, 16.31 ]

Omu 2008 14 50 (20) 8 24 (12) 10.2 % 26.00 [ 12.62, 39.38 ]

Peivandi 2010 15 48.3 (0.16) 15 17 (0.09) 12.5 % 31.30 [ 31.21, 31.39 ]

Scott 1998 30 27 (20.3) 18 15.3 (17.4) 10.9 % 11.70 [ 0.87, 22.53 ]

-50 -25 0 25 50


(Continued . . . )





Sigman 2006 12 28.6 (38.1) 9 37.6 (33) 5.8 % -9.00 [ -39.49, 21.49 ]

Zavaczki 2003 10 33.5 (29.8) 10 19 (14.4) 8.2 % 14.50 [ -6.01, 35.01 ]

Subtotal (95% CI) 244 210 100.0 % 13.47 [ 3.45, 23.49 ]



2 Total sperm motility at 6 months

Balercia 2005 15 61.07 (9.07) 15 43.4 (9.85) 6.5 % 17.67 [ 10.89, 24.45 ]

Balercia 2009 30 39.41 (6.8) 30 34.93 (8.04) 14.5 % 4.48 [ 0.71, 8.25 ]

Lenzi 2004 30 31.11 (13.46) 26 29.55 (9.5) 7.7 % 1.56 [ -4.48, 7.60 ]

Safarinejad 2009 116 29.2 (2.9) 118 22.9 (2.2) 31.4 % 6.30 [ 5.64, 6.96 ]

Safarinejad 2009a 106 27.6 (2.2) 106 23.1 (2.1) 31.6 % 4.50 [ 3.92, 5.08 ]

Sigman 2006 12 32.3 (24.2) 9 40 (33) 0.6 % -7.70 [ -33.24, 17.84 ]

Suleiman 1996 52 48.9 (15.5) 35 35.9 (12.8) 7.8 % 13.00 [ 7.02, 18.98 ]

Subtotal (95% CI) 361 339 100.0 % 6.28 [ 4.36, 8.21 ]



3 Total sperm motility at 9 months or more

Balercia 2005 15 49 (7.8) 15 42.73 (10.02) 17.8 % 6.27 [ -0.16, 12.70 ]

Balercia 2009 30 32.93 (6.33) 30 35.3 (8) 31.9 % -2.37 [ -6.02, 1.28 ]

Safarinejad 2009a 106 24.2 (2.1) 106 22.8 (2.2) 50.3 % 1.40 [ 0.82, 1.98 ]

Subtotal (95% CI) 151 151 100.0 % 1.07 [ -2.29, 4.43 ]



-50 -25 0 25 50




Analysis 1.12. Comparison 1 Antioxidant(s) versus control, Outcome 12 Sperm concentration over time.



Outcome: 12 Sperm concentration over time



1 Sperm concentration at 3 months or less

Ciftci 2009 60 21.85 (11.08) 60 22.32 (22) 16.0 % -0.47 [ -6.70, 5.76 ]

Conquer 2000 10 44.6 (41.1) 9 43.1 (40.5) 6.4 % 1.50 [ -35.23, 38.23 ]

Greco 2005 32 27.5 (24.6) 32 20.3 (21.2) 14.6 % 7.20 [ -4.05, 18.45 ]

Peivandi 2010 15 46 (3.62) 15 16.5 (7.26) 16.4 % 29.50 [ 25.39, 33.61 ]

Rolf 1999 15 20.6 (13.5) 16 25 (17.8) 14.6 % -4.40 [ -15.48, 6.68 ]

Wang 1983 11 12.8 (4.7) 7 8.5 (5.6) 16.3 % 4.30 [ -0.69, 9.29 ]

Zavaczki 2003 10 16.1 (10.2) 10 10.9 (7.4) 15.6 % 5.20 [ -2.61, 13.01 ]

Subtotal (95% CI) 153 149 100.0 % 6.79 [ -5.09, 18.66 ]



2 Sperm concentration 6 months

Balercia 2005 15 37.4 (16.42) 15 33.73 (14.36) 4.8 % 3.67 [ -7.37, 14.71 ]

Balercia 2009 30 44.93 (19.3) 30 46.37 (19.77) 5.8 % -1.44 [ -11.33, 8.45 ]

Lenzi 2004 30 22.09 (9.05) 26 22.17 (16.95) 9.4 % -0.08 [ -7.36, 7.20 ]

Safarinejad 2009 116 32.1 (6.8) 118 23.5 (5.8) 31.9 % 8.60 [ 6.98, 10.22 ]

Safarinejad 2009a 106 26.4 (4.4) 106 20.8 (4.3) 33.9 % 5.60 [ 4.43, 6.77 ]

Wang 1983 11 11.1 (5.8) 7 8.3 (5.6) 14.2 % 2.80 [ -2.58, 8.18 ]

Subtotal (95% CI) 308 302 100.0 % 5.12 [ 2.53, 7.72 ]



3 Sperm concentration at 9 months or more

Balercia 2005 15 33.27 (13.62) 15 30.13 (9.3) 1.5 % 3.14 [ -5.21, 11.49 ]

Balercia 2009 30 44.18 (20.43) 30 49.56 (20.47) 1.0 % -5.38 [ -15.73, 4.97 ]

Safarinejad 2009a 106 22.8 (3.8) 106 21.2 (3.8) 97.6 % 1.60 [ 0.58, 2.62 ]

Subtotal (95% CI) 151 151 100.0 % 1.56 [ 0.55, 2.57 ]



-20 -10 0 10 20




Analysis 1.13. Comparison 1 Antioxidant(s) versus control, Outcome 13 Side effects.



Outcome: 13 Side effects



1 gastrointestinal

Cavallini 2004 2/39 2/47 1.21 [ 0.16, 9.01 ]

Kessopoulou 1995 0/15 1/15 0.14 [ 0.00, 6.82 ]

Safarinejad 2009a 0/106 0/106 0.0 [ 0.0, 0.0 ]

Sigman 2006 0/12 0/9 0.0 [ 0.0, 0.0 ]

Tremellen 2007 3/37 0/20 4.94 [ 0.44, 55.27 ]

Zavaczki 2003 2/10 1/10 2.11 [ 0.19, 23.05 ]

Subtotal (95% CI) 219 207 1.63 [ 0.48, 5.58 ]




2 euphoria

Cavallini 2004 2/39 2/47 1.21 [ 0.16, 9.01 ]

Subtotal (95% CI) 39 47 1.21 [ 0.16, 9.01 ]





0.002 0.1 1 10 500


Analysis 1.14. Comparison 1 Antioxidant(s) versus control, Outcome 14 Sperm motility at 3 months or less.

Sperm motility at 3 months or less

Study Heading one Heading two

L-carnitine + Acetyl-carnitine versus placebo (median and interquartile range)

Cavallini 2004 L-carnitine + Acetyl-carnitine

Median=22.3 (n=39)

Interquartile range =28.4-15.2

Placebo

Median= 14.0 (n=47)

Interquartile range=17.4-5.1

Combined antioxidants versus no treatment

Galatioto 2008 Combined antioxidants

% of motile sperm =58% (n=20)

No treatment

% of motile sperm =51% (n=22)



Sperm motility at 3 months or less (Continued)

Vitamin E versus placebo

Kessopoulou 1995 Vitamin E

Median=7 (n=15)

min/max= -27-34

Placebo

Median=7 (n=15)

min/max= -33-36

L-carnitine versus placebo

Lenzi 2003 L-carnitine

Mean=11(n=43)

no sd given

Placebo

Mean=8.8 (n=43)

no sd given

Pentoxifylline versus Placebo

Merino 1997 Pentoxifylline

Median=35.5 (n=25)

Range=31.5-39.5

Placebo

Median=33.5 (n=22)

Range=28.5-37.5

Analysis 1.15. Comparison 1 Antioxidant(s) versus control, Outcome 15 Sperm motility at 6 months.

Sperm motility at 6 months



Cavallini 2004 L-carnitine + acetyl-carnitine

Median=23.6 (n=39)


Placebo

Median=13.2 (n=47)


Pentoxifylline versus placebo

Merino 1997 Pentoxifylline

Median=42 (n=25)

Range=38-46

Placebo

Median=31.5 (22)

Range=28-35

Folic acid versus placebo

Wong 2002 Folic acid

Median=35 (n=22)

Range=5-65

Placebo

Median=30 (n=25)

Range=5-80

Zinc versus placebo

Wong 2002 Zinc

Median=35 (n=23)

Range=10-65

Placebo

Median=30 (n=25)



Sperm motility at 6 months (Continued)

Range=5-80

Zinc + folic acid versus placebo

Wong 2002 Zinc + folic acid

Median=35 (n=24)

Range 5-70

Placebo

Median=30 (n=25)

Range=5-80

Analysis 1.16. Comparison 1 Antioxidant(s) versus control, Outcome 16 Sperm concentration at 3 months

or less.

Sperm concentration at 3 months or less



Cavallini 2004 L-carnitine + acetyl-carnitine

Median=20.9 (n=39)


Placebo

Median=12.3 (n=47)


Vitamin E versus placebo

Kessopoulou 1995 Vitamin E

Median= -15 (n=15)

min/max= -58-59

Placebo

Median=0 (n=15)

min/max= -37-160

L-carnitine versus placebo

Lenzi 2003 L-carnitine

Mean= 9 (1st phase data) (n=43)

no sd given

Placebo

Mean=5.3 (n=43)

no sd given

Analysis 1.17. Comparison 1 Antioxidant(s) versus control, Outcome 17 Sperm concentration at 6 months.

Sperm concentration at 6 months


L-carnitine + acetyl-carnitine versus placebo

Cavallini 2004 L-carnitine + acetyl-carniitne

Median=20.6 (n=39)


Placebo

Median=10.9 (n=47)


Folic acid versus Placebo



Sperm concentration at 6 months (Continued)

Wong 2002 Folic acid

Median=14 (n=22)

Range=0.9-130

Placebo

Median=9 (n=25)

Range=0.8-80

Zinc versus Placebo

Wong 2002 Zinc

Median=16 (n= 23)

Range=0.6-80

Placebo

Median=9 (n= 25)

Range=0.8-80

Analysis 1.18. Comparison 1 Antioxidant(s) versus control, Outcome 18 Pregnancy.



Outcome: 18 Pregnancy



1 Pregnancy rate of trials that also report live birth

Omu 1998 11/49 2/48 4.75 [ 1.49, 15.20 ]

Suleiman 1996 11/52 0/35 6.64 [ 1.84, 23.93 ]

Subtotal (95% CI) 101 83 5.53 [ 2.34, 13.08 ]




2 Pregnancy rate only reported

Balercia 2005 9/45 3/15 1.00 [ 0.23, 4.26 ]

Balercia 2009 6/30 3/30 2.16 [ 0.53, 8.82 ]

Cavallini 2004 9/39 1/47 7.50 [ 2.01, 27.98 ]

Galatioto 2008 1/20 0/22 8.17 [ 0.16, 413.39 ]

Lenzi 2003 6/43 0/43 8.37 [ 1.61, 43.58 ]

Lenzi 2004 4/30 0/26 7.20 [ 0.95, 54.34 ]

Peivandi 2010 3/15 0/15 8.57 [ 0.82, 89.45 ]

Rolf 1999 0/15 0/16 0.0 [ 0.0, 0.0 ]

Safarinejad 2009a 0/106 0/106 0.0 [ 0.0, 0.0 ]

0.005 0.1 1 10 200


(Continued . . . )



(. . . Continued)Study or subgroup Experimental Control Peto Odds Ratio Peto Odds Ratio


Sigman 2006 1/10 0/10 7.39 [ 0.15, 372.38 ]

Tremellen 2007 20/38 4/20 3.75 [ 1.26, 11.16 ]

Wang 1983 0/11 0/7 0.0 [ 0.0, 0.0 ]

Zavaczki 2003 1/10 0/10 7.39 [ 0.15, 372.38 ]

Subtotal (95% CI) 412 367 4.02 [ 2.34, 6.92 ]




Total (95% CI) 513 450 4.40 [ 2.78, 6.97 ]





0.005 0.1 1 10 200


Analysis 2.1. Comparison 2 Live birth versus pregnancy, Outcome 1 Live birth.


Comparison: 2 Live birth versus pregnancy

Outcome: 1 Live birth



1 live birth

Omu 1998 8/49 2/48 53.6 % 3.67 [ 1.00, 13.51 ]

Suleiman 1996 9/52 0/35 46.4 % 6.33 [ 1.56, 25.63 ]

Subtotal (95% CI) 101 83 100.0 % 4.73 [ 1.82, 12.27 ]




2 pregnancy

Omu 1998 11/49 2/48 54.9 % 4.75 [ 1.49, 15.20 ]

Suleiman 1996 11/52 0/35 45.1 % 6.64 [ 1.84, 23.93 ]

Subtotal (95% CI) 101 83 100.0 % 5.53 [ 2.34, 13.08 ]

0.005 0.1 1 10 200


(Continued . . . )



(. . . Continued)Study or subgroup Experimental Control Peto Odds Ratio Weight Peto Odds Ratio





0.005 0.1 1 10 200


Analysis 3.1. Comparison 3 Head to head antioxidant(s), Outcome 1 Pregnancy per couple randomised.


Comparison: 3 Head to head antioxidant(s)

Outcome: 1 Pregnancy per couple randomised

Study or subgroup Antioxidant ’a’ Antioxidant ’b’ Peto Odds Ratio Weight Peto Odds Ratio


1 L acetyl carnitine + L carnitine versus L acetyl carnitine

Balercia 2005 2/7 2/15 100.0 % 2.66 [ 0.27, 25.80 ]

Subtotal (95% CI) 7 15 100.0 % 2.66 [ 0.27, 25.80 ]

Total events: 2 (Antioxidant ’a’), 2 (Antioxidant ’b’)



2 L acetyl carnitine + L carnitine versus L- carnitine

Balercia 2005 3/8 2/15 100.0 % 3.89 [ 0.51, 29.76 ]

Subtotal (95% CI) 8 15 100.0 % 3.89 [ 0.51, 29.76 ]




3 L acetyl carnitine + L carnitine versus Vitamin E + Vitamin C

Li 2005 10/90 2/60 100.0 % 2.86 [ 0.86, 9.49 ]

Subtotal (95% CI) 90 60 100.0 % 2.86 [ 0.86, 9.49 ]





0.01 0.1 1 10 100

Favours antioxidant ’b’ Favours antioxidant ’a’



Analysis 3.2. Comparison 3 Head to head antioxidant(s), Outcome 2 Sperm total motility at 3 months or

less.



Outcome: 2 Sperm total motility at 3 months or less

Study or subgroup Antioxidant b Antioxidant b Mean Difference Weight Mean Difference


1 Ethylcysteine 600mg/day vs Vitamin E

Akiyama 1999 5 40.9 (30.1) 5 42.8 (34.4) 100.0 % -1.90 [ -41.97, 38.17 ]

Subtotal (95% CI) 5 5 100.0 % -1.90 [ -41.97, 38.17 ]



2 Docosahexaenoic acid (DHA) 400g/day vs Docosahexaenoic acid 800mg/day

Conquer 2000 9 39.4 (24.3) 10 32 (16.1) 100.0 % 7.40 [ -11.35, 26.15 ]

Subtotal (95% CI) 9 10 100.0 % 7.40 [ -11.35, 26.15 ]



3 Ascorbic Acid 200mg/day versus Ascorbic Acid 1000mg/day

Dawson 1990 10 51 (22.1) 10 94 (32) 100.0 % -43.00 [ -67.10, -18.90 ]

Subtotal (95% CI) 10 10 100.0 % -43.00 [ -67.10, -18.90 ]



4 Vitamin E + Selenium versus Vitamin B at 3 months

Keskes-Ammar 2003 28 39 (19) 26 39 (21) 100.0 % 0.0 [ -10.71, 10.71 ]

Subtotal (95% CI) 28 26 100.0 % 0.0 [ -10.71, 10.71 ]



5 Zinc versus Zinc + Vitamin E at 3 months

Omu 2008 6 49 (12) 12 50 (18) 100.0 % -1.00 [ -15.00, 13.00 ]

Subtotal (95% CI) 6 12 100.0 % -1.00 [ -15.00, 13.00 ]



6 Zinc versus Zinc + Vitamin E + Vitamin C at 3 months

Omu 2008 6 49 (12) 6 50 (20) 100.0 % -1.00 [ -19.66, 17.66 ]

Subtotal (95% CI) 6 6 100.0 % -1.00 [ -19.66, 17.66 ]



7 Zinc + Vitamin E versus Zinc + Vitamin E + Vitamin C at 3 months

Omu 2008 12 50 (18) 6 50 (20) 100.0 % 0.0 [ -18.97, 18.97 ]

Subtotal (95% CI) 12 6 100.0 % 0.0 [ -18.97, 18.97 ]

-50 -25 0 25 50

Antioxidant b Antioxidant a

(Continued . . . )



(. . . Continued)Study or subgroup Antioxidant b Antioxidant b Mean Difference Weight Mean Difference




8 Selenium versus combined antioxidants

Scott 1998 16 30.2 (22.8) 30 27 (20.3) 100.0 % 3.20 [ -10.13, 16.53 ]

Subtotal (95% CI) 16 30 100.0 % 3.20 [ -10.13, 16.53 ]




Li 2005 90 38.29 (9.67) 60 15.24 (7.89) 100.0 % 23.05 [ 20.23, 25.87 ]

Subtotal (95% CI) 90 60 100.0 % 23.05 [ 20.23, 25.87 ]



-50 -25 0 25 50

Antioxidant b Antioxidant a

Analysis 3.3. Comparison 3 Head to head antioxidant(s), Outcome 3 Sperm total motility at 6 months.



Outcome: 3 Sperm total motility at 6 months

Study or subgroup Antioxidant ’a’ Antioxidant ’b’ Mean Difference Weight Mean Difference


1 L-aceytl carnitine +L-carnitine versus L-carnitine at 6 months

Balercia 2005 7 61.07 (9.07) 15 64.53 (8.41) 100.0 % -3.46 [ -11.41, 4.49 ]

Subtotal (95% CI) 7 15 100.0 % -3.46 [ -11.41, 4.49 ]



2 L-acetyl carnitine + L-carnitine versus L-acetyl carnitine at 6 months

Balercia 2005 8 61.07 (9.07) 15 60.43 (10.46) 100.0 % 0.64 [ -7.58, 8.86 ]

Subtotal (95% CI) 8 15 100.0 % 0.64 [ -7.58, 8.86 ]



3 Selenium versus N-acetyl-cysteine at 26 weeks (6 months)

Safarinejad 2009 58 26.1 (2.9) 118 24.8 (2.9) 100.0 % 1.30 [ 0.39, 2.21 ]

Subtotal (95% CI) 58 118 100.0 % 1.30 [ 0.39, 2.21 ]

-10 -5 0 5 10

Favours antioxidant b Favours antioxidant a

(Continued . . . )



(. . . Continued)Study or subgroup Antioxidant ’a’ Antioxidant ’b’ Mean Difference Weight Mean Difference




4 Selenium versus selenium plus N-acetyl-cysteine at 26 weeks (6 months)

Safarinejad 2009 58 26.1 (2.9) 58 29.2 (2.9) 100.0 % -3.10 [ -4.16, -2.04 ]

Subtotal (95% CI) 58 58 100.0 % -3.10 [ -4.16, -2.04 ]



5 N-acetyl-cysteine vs selenium plus N-acetyl-cysteine at 26 weeks

Safarinejad 2009 118 24.8 (2.9) 58 29.2 (2.9) 100.0 % -4.40 [ -5.31, -3.49 ]

Subtotal (95% CI) 118 58 100.0 % -4.40 [ -5.31, -3.49 ]




-10 -5 0 5 10

Favours antioxidant b Favours antioxidant a

Analysis 3.4. Comparison 3 Head to head antioxidant(s), Outcome 4 Sperm total motility at 9 months or

more.



Outcome: 4 Sperm total motility at 9 months or more




Balercia 2005 7 49 (7.8) 15 54.27 (8.96) 100.0 % -5.27 [ -12.61, 2.07 ]

Subtotal (95% CI) 7 15 100.0 % -5.27 [ -12.61, 2.07 ]




Balercia 2005 8 49 (7.8) 15 50.57 (5.71) 100.0 % -1.57 [ -7.70, 4.56 ]

Subtotal (95% CI) 8 15 100.0 % -1.57 [ -7.70, 4.56 ]




-20 -10 0 10 20




Analysis 3.5. Comparison 3 Head to head antioxidant(s), Outcome 5 Sperm concentration at 3 months or

less.



Outcome: 5 Sperm concentration at 3 months or less



1 Ethylcysteine 600mg/day vs Vitamin E

Akiyama 1999 5 20.1 (14.8) 5 17.9 (15.6) 100.0 % 2.20 [ -16.65, 21.05 ]

Subtotal (95% CI) 5 5 100.0 % 2.20 [ -16.65, 21.05 ]



2 Docosahexaenoic acid (DHA) 400g/day versus Docosahexaenoic acid (DHA) 800g/day

Conquer 2000 9 37.8 (36.9) 10 44.6 (41.1) 100.0 % -6.80 [ -41.87, 28.27 ]

Subtotal (95% CI) 9 10 100.0 % -6.80 [ -41.87, 28.27 ]



3 L-carnitine versus Vitamin E + Vitamin C

Li 2005a 32 34.6 (7.4) 31 19.1 (4.5) 100.0 % 15.50 [ 12.49, 18.51 ]

Subtotal (95% CI) 32 31 100.0 % 15.50 [ 12.49, 18.51 ]




-100 -50 0 50 100




Analysis 3.6. Comparison 3 Head to head antioxidant(s), Outcome 6 Sperm concentration at 6 months.



Outcome: 6 Sperm concentration at 6 months




Balercia 2005 7 37.4 (16.42) 15 45.53 (21.42) 100.0 % -8.13 [ -24.42, 8.16 ]

Subtotal (95% CI) 7 15 100.0 % -8.13 [ -24.42, 8.16 ]




Balercia 2005 8 37.4 (16.42) 15 39.57 (19.99) 100.0 % -2.17 [ -17.40, 13.06 ]

Subtotal (95% CI) 8 15 100.0 % -2.17 [ -17.40, 13.06 ]



3 Selenium versus N-acetyl-cysteine at 26 weeks (6 months)

Safarinejad 2009 58 27.6 (6.4) 118 26.8 (5.3) 100.0 % 0.80 [ -1.10, 2.70 ]

Subtotal (95% CI) 58 118 100.0 % 0.80 [ -1.10, 2.70 ]



4 Selenium versus selenium plus N-acetyl-cysteine at 26 weeks (6 months)

Safarinejad 2009 58 27.6 (6.4) 58 32.1 (6.8) 100.0 % -4.50 [ -6.90, -2.10 ]

Subtotal (95% CI) 58 58 100.0 % -4.50 [ -6.90, -2.10 ]



5 N-acetyl-cysteine vs selenium plus N-acetyl-cysteine at 26 weeks

Safarinejad 2009 118 26.8 (5.3) 58 32.1 (6.8) 100.0 % -5.30 [ -7.29, -3.31 ]

Subtotal (95% CI) 118 58 100.0 % -5.30 [ -7.29, -3.31 ]




-20 -10 0 10 20




Analysis 3.7. Comparison 3 Head to head antioxidant(s), Outcome 7 Sperm concentration at 9 months or

more.



Outcome: 7 Sperm concentration at 9 months or more




Balercia 2005 7 33.27 (13.62) 15 39.4 (13.93) 100.0 % -6.13 [ -18.44, 6.18 ]

Subtotal (95% CI) 7 15 100.0 % -6.13 [ -18.44, 6.18 ]




Balercia 2005 8 33.27 (13.62) 15 31.21 (8.6) 100.0 % 2.06 [ -8.33, 12.45 ]

Subtotal (95% CI) 8 15 100.0 % 2.06 [ -8.33, 12.45 ]




-20 -10 0 10 20


Analysis 3.8. Comparison 3 Head to head antioxidant(s), Outcome 8 Side effects.



Outcome: 8 Side effects

Study or subgroup Experimental Control Odds Ratio Odds Ratio

n/N n/N M-H,Fixed,95% CI M-H,Fixed,95% CI


Li 2005 0/90 0/60 0.0 [ 0.0, 0.0 ]

Total (95% CI) 90 60 0.0 [ 0.0, 0.0 ]




0.01 0.1 1 10 100

Favours antioxidant ’a’ Favours antioxidant ’b’



Analysis 3.9. Comparison 3 Head to head antioxidant(s), Outcome 9 Sperm concentration at 6 months.

Sperm concentration at 6 months


Zinc versus Folic acid

Wong 2002 Zinc

Median=16

Range=0.6-80

Folic acid

Median=14

Range=0.9-130

Zinc versus Zinc + Folic acid

Wong 2002 Zinc

Median= 16

Range=0.6-80

Zinc + Folic acid

Median=12

Range=0.5-180

Analysis 3.10. Comparison 3 Head to head antioxidant(s), Outcome 10 Sperm motility at 6 months.

Sperm motility at 6 months


Zinc versus Folic acid

Wong 2002 Zinc

Median=35

Range=10-65

Folic acid

Median=35

Range=5-65

A P P E N D I C E S

Appendix 1. MEDLINE search strategy

1 exp male infertility/ (19113)

2 (asthenozoospermia or oligospermia or azoospermia).tw. (4464)

3 exp Spermatozoa/ (48125)

4 Sperm$.tw. (85274)

5 (male$ adj2 subfertil$).tw. (484)

6 (male$ adj2 infertil$).tw. (5719)

7 (subfertil$ adj2 men).tw. (356)

8 (infertil$ adj2 men).tw. (2400)

9 (male$ adj2 fertility).tw. (2706)

10 semen.tw. (16927)

11 oligoasthenoteratozoospermi$.tw. (185)

12 or/1-11 (108373)



13 exp antioxidants/ or free radical scavengers/ (280006)

14 (antioxidant$ or radical scavengers).tw. (69599)

15 exp vitamins/ or exp ascorbic acid/ or exp dehydroascorbic acid/ or exp vitamin a/ or exp vitamin e/ or exp vitamin u/ or exp alpha-

tocopherol/ or exp beta carotene/ or exp beta-tocopherol/ or exp gamma-tocopherol/ (234713)

16 vitamin$.tw. (111181)

17 exp Zinc/ (41085)

18 exp Selenium/ (13920)

19 (Glutathione$ or folate).tw. (81376)

20 exp Ubiquinone/ (5352)

21 ubiquin$.tw. (5228)

22 coenzyme q10.tw. (1462)

23 exp Carnitine/ (6812)

24 (carnitine$ or carotenoid$).tw. (17142)

25 (astaxanthin$ or lycopene$).tw. (2711)

26 menevit.tw. (1)

27 multivitamin$.tw. (1967)

28 (betacarotene$ or beta carotene$).tw. (7738)

29 ascorbic acid.tw. (18104)

30 n-acetylcysteine.tw. (5514)

31 alpha-tocopherol$.tw. (10653)

32 exp Pentoxifylline/ (3302)

33 Pentoxifylline$.tw. (3079)

34 (fish adj2 oil$).tw. (5536)

35 omega$.tw. (23211)

36 exp fatty acids/ or exp fish oils/ or exp cod liver oil/ or exp fatty acids, omega-3/ or exp plant oils/ (321518)

37 fatty acid$.tw. (109608)

38 (plant adj4 oil$).tw. (899)

39 l-arginine$.tw. (25627)

40 flavonoid$.tw. (11562)

41 carotenoid$.tw. (8425)

42 riboflavin$.tw. (5897)

43 pycnogenol$.tw. (177)

44 lutein$.tw. (27811)

45 lipoic acid$.tw. (1986)

46 or/13-45 (968481)

47 46 and 12 (8395)

48 randomized controlled trial.pt. (280587)

49 controlled clinical trial.pt. (80011)

50 randomized.ab. (190341)

51 placebo.tw. (118552)

52 clinical trials as topic.sh. (146404)

53 randomly.ab. (138335)

54 trial.ti. (82364)

55 (crossover or cross-over or cross over).tw. (43907)

56 or/48-55 (666167)

57 (animals not (humans and animals)).sh. (3345663)

58 56 not 57 (615399)

59 47 and 58 (247)

60 from 59 keep 1-247 (247)



Appendix 2. EMBASE search strategy




4 Sperm$.tw. (62512)






10 semen.tw. (11264)


12 or/1-11 (74872)

13 vitamin$.tw. (83637)

14 exp Zinc/ (44487)









23 menevit.tw. (6)









32 omega$.tw. (19649)








40 lutein$.tw. (21048)


42 exp antioxidant/ (46224)

43 exp vitamin/ or exp ascorbic acid/ or exp carotenoid/ or exp multivitamin/ or vitamin b group/ (246879)

44 exp fatty acid/ (244186)

45 exp vegetable oil/ (25806)

46 exp fish oil/ (7175)

47 exp cod liver oil/ (573)

48 exp omega 3 fatty acid/ (8974)

49 or/13-48 (735430)

50 12 and 49 (5848)

51 Clinical Trial/ (579096)



52 Randomized Controlled Trial/ (181492)

53 exp randomization/ (27531)

54 Single Blind Procedure/ (9051)

55 Double Blind Procedure/ (76202)

56 Crossover Procedure/ (22447)

57 Placebo/ (138119)

58 Randomi?ed controlled trial$.tw. (37822)

59 Rct.tw. (3250)

60 random allocation.tw. (669)

61 randomly allocated.tw. (10813)

62 allocated randomly.tw. (1393)

63 (allocated adj2 random).tw. (573)

64 Single blind$.tw. (7937)

65 Double blind$.tw. (88810)

66 ((treble or triple) adj blind$).tw. (149)

67 placebo$.tw. (116382)

68 prospective study/ (90830)

69 or/51-68 (760080)

70 case study/ (6847)

71 case report.tw. (127165)

72 abstract report/ or letter/ (526689)

73 or/70-72 (658112)

74 69 not 73 (733696)

75 50 and 74 (544)

76 (2009$ or 2010$).em. (774638)

77 75 and 76 (59)

78 from 77 keep 1-59 (59)

Appendix 3. CENTRAL search strategy




4 Sperm$.tw. (1726)






10 semen.tw. (510)


12 or/1-11 (2087)





16 vitamin$.tw. (7367)

17 exp Zinc/ (930)











26 menevit.tw. (1)









35 omega$.tw. (885)









44 lutein$.tw. (1402)


46 or/13-45 (36854)

47 46 and 12 (253)

48 from 47 keep 1-253 (253)

Appendix 4. CINAHL search strategy

CINAHL search from inception until 13.08.08



3 (male$ or men or man).tw. (60126)


5 Sperm$.tw. (585)

6 or/1-5 (60531)






11 exp Zinc/ (1056)

12 (zinc or selenium).tw. (1529)


14 exp Glutathione Peroxidase/ or exp folic acid/ (2362)



17 (ubiquin$ or folic acid).tw. (988)





22 menevit.tw. (2)



23 or/7-22 (18483)

24 6 and 23 (1359)

25 exp fertilization in vitro/ or exp sperm injections, intracytoplasmic/ or exp Insemination, Artificial, Homologous/ (947)

26 (in vitro fertilisation or intracytoplasmic sperm injection$).tw. (148)

27 (intrauterine adj3 insemination$).tw. (45)

28 (ivf or icsi or iui).tw. (332)

29 in-vitro fertilisation.tw. (90)

30 in vitro fertilization.tw. (287)

31 ART.tw. (5558)

32 Artificial reproduc$ technique$.tw. (1)

33 or/25-32 (6666)

34 24 and 33 (8)

35 exp clinical trials/ (61758)

36 Clinical trial.pt. (32434)

37 (clinic$ adj trial$1).tw. (14019)

38 ((singl$ or doubl$ or trebl$ or tripl$) adj (blind$3 or mask$3)).tw. (8276)

39 Randomi?ed control$ trial$.tw. (12024)

40 Random assignment/ (18434)

41 Random$ allocat$.tw. (1272)

42 Placebo$.tw. (11470)

43 Placebos/ (4474)

44 Quantitative studies/ (4044)

45 Allocat$ random$.tw. (74)

46 or/35-45 (85043)

47 34 and 46 (3)

48 from 47 keep 1-3 (3)

CINAHL search from 13.08.08 until 22.02.10

# Query Limiters/Expanders Last Run Via Results

S5 S1 and S4 Search modes

- Boolean/Phrase

Interface

- EBSCOhost

Search Screen

- Advanced Search

Database

- CINAHL Plus

31

S4 S2 or S3 Search modes

- Boolean/Phrase

Interface

- EBSCOhost

Search Screen

- Advanced Search

Database

- CINAHL Plus

1167

S3 (“sperm”) or (MH “Sperm

Count”) or (MH “Spermato-

zoa”)

Search modes

- Boolean/Phrase

Interface

- EBSCOhost

Search Screen

- Advanced Search

Database

- CINAHL Plus

1074



(Continued)

S2 “male infertility” Search modes

- Boolean/Phrase

Interface

- EBSCOhost

Search Screen

- Advanced Search

Database

- CINAHL Plus

168

S1 (MH “Antioxidants+”) or

(MH “Berries+”) or

(MH “Chlorophyll”) or (MH

“Flavonoids+”) or (MH “Ly-

copene”) or (MH “Polyphe-

nols+”)

Search modes

- Boolean/Phrase

Interface

- EBSCOhost

Search Screen

- Advanced Search

Database

- CINAHL Plus

8581

Appendix 5. PsycINFO search strategy




4 Sperm$.tw. (1871)






10 semen.tw. (268)


12 or/1-11 (2254)






17 exp Zinc/ (317)









26 menevit.tw. (0)











35 omega$.tw. (908)









44 lutein$.tw. (1034)


46 or/13-45 (11595)

47 46 and 12 (29)

48 from 47 keep 1-29 (29)

Appendix 6. AMED search strategy




4 Sperm$.tw. (151)






10 semen.tw. (82)


12 or/1-11 (285)






17 exp Zinc/ (92)









26 menevit.tw. (0)











35 omega$.tw. (173)









44 lutein$.tw. (47)


46 or/13-45 (6342)

47 46 and 12 (24)

48 from 47 keep 1-24 (24)

Appendix 7. MDSG Specialised Register search strategy

Keywords CONTAINS “antioxidants” or “antioxidant levels” or “vitamin” or “vitamin A” or “vitamin B” or “Vitamin-B-12” or

“Vitamin-B-12-Therapeutic-Use” or “vitamin B6” or “vitamin C” or “Vitamin D” or “vitamin E” or “vitamins” or “selenium” or

“folic acid” or “glutathione” or “Menevit anti-oxidant” or “carnitene” or “carnitine” or “ascorbic acid” or “zinc” or “fatty acids” or

“oil” or “fish oils” or “plant extracts” or Title CONTAINS “fatty acids” or “oil” or “fish oils” or “plant extracts or ”antioxidants“ or

”antioxidant levels“ or ”vitamin“ or ”vitamin A“ or ”vitamin B“ or ”Vitamin-B-12“ or ”Vitamin-B-12-Therapeutic-Use“ or ”vitamin

B6“ or ”vitamin C“ or ”Vitamin D“ or ”vitamin E“ or ”vitamins“ or ”selenium“ or ”folic acid“ or ”glutathione“ or ”Menevit anti-

oxidant“ or ”carnitene“ or ”carnitine“ or ”ascorbic acid“ or ”zinc“

AND

Keywords CONTAINS ”IVF“ or ”ICSI“ or ”idiopathic asthenospermia“ or ”idiopathic oligozoospermia“ or ”in-vitro fertilisation “ or

”in-vitro fertilisation procedure“ or ”in vitro fertilization“ or ”intracytoplasmic sperm injection“ or ”intracytoplasmic morphologically

selected sperm injection“ or ”superovulation“ or ”superovulation induction“ or ”IUI“ or ”insemination, intrauterine “ or ”Intrauterine

Insemination“ or ”ART“ or ”artificial insemination“ or ”Sperm“ or ”sperm DNA integrity“ or ”sperm damage“ or ”sperm quality“ or

”sperm parameters“ or ”oligo-asthenozoospermia“ or ”Oligoasthenospermia“ or ”oligoasthenoteratozoospermia“ or ”oligospermia“ or

”oligozoospermia“ or ”asthenospermia“ or ”asthenozoospermia“ or ”assisted reproduction techniques“ or ”azoospermia“

Appendix 8. ’The World Health Organization International Trials Registry Platform’ search portal

1) Antioxidants AND men

2) Vitamins AND men

3) Antioxidant* AND male

4) Vitamin* AND male

5) Infertiltiy AND men

Appendix 9. ’ClinicalTrials.gov’ trials register

1) Antixidants AND men

2) Vitamins AND men



Appendix 10. OpenSigle

1) Antioxidant*

2) Vitamin*

3) Infertility AND Men

W H A T ’ S N E W

Last assessed as up-to-date: 21 August 2010.

Date Event Description

3 May 2011 Amended 2.1 Analysis edited to fixed effect Peto. The conclusions remain the same.

H I S T O R Y

Protocol first published: Issue 4, 2008

Review first published: Issue 1, 2011

Date Event Description

8 March 2011 Amended Changed summary of findings table to reflect quality of studies

21 December 2010 Amended Minor edits made - no changes to conclusions

4 May 2007 New citation required and major changes Substantive amendment

C O N T R I B U T I O N S O F A U T H O R S

MGS: initiated, conceptualised and wrote the protocol. Performed the searches, selected trials for inclusion, assessed quality, performed

data extraction, entered data and wrote the final review.

RH: advised and supervised both the protocol and review, helped select trials for inclusion and wrote the implications for practice and

research and assisted with the abstract.

JB: co-drafted the protocol. Selected trials for inclusion, assessed quality and performed data extraction. Julie also provided advice on

the data analysis and helped with incorporating the editorial comments into the review.

AY: co-drafted the protocol and provided Word document concerning sperm DNA for background and provided technical advice.

MS: co-drafted the protocol and provided technical advice.



D E C L A R A T I O N S O F I N T E R E S T

None known

S O U R C E S O F S U P P O R T

Internal sources

• Cochrane Menstrual Disorders and Subfertility Group, Not specified.

External sources

• No sources of support supplied

D I F F E R E N C E S B E T W E E N P R O T O C O L A N D R E V I E W

Sperm outcomes of concentration and motility were added as these two sperm outcomes are thought to reflect the oxidative process.

A study by El-Taieb (El-Taieb 2009) states that ”increased ROS generation and reduced antioxidant capacity is negatively correlated

with sperm concentration and motility in infertile men“.

The comparisons ’antioxidant versus placebo’ and ’antioxidants versus no treatment’ were combined as one comparison ’antioxidants

versus control’ and then it was stated under sensitivity analysis whether exclusion of those that failed to use placebo would have altered

the conclusions - as per statistical advice in editorial comments.

Subgrouping and sensitivity analysis were performed on the outcomes of live birth and pregnancy in order to assess the potential of

overestimation of benefit and reporting bias.

Sensitivity analysis was performed on trials that enrolled couples undergoing IVF or ICSI or IUI.

I N D E X T E R M S

Medical Subject Headings (MeSH)

Antioxidants [∗therapeutic use]; DNA Damage; Infertility, Male [∗drug therapy; etiology]; Live Birth; Oxidative Stress [∗drug effects];

Pregnancy Rate; Sperm Count; Sperm Motility [drug effects]; Spermatozoa [drug effects]

MeSH check words

Female; Humans; Male; Pregnancy



Documents

Antioxidants for Male Sub Fertility (Review)