GRACE CHEN18 TH OCTOBER, 2014. OCCUPATIONAL AND ENVIRONMENTAL RISK FACTORS FOR MOTOR NEURONE DISEASE IN NZ Case - Control Study

GRACE CHEN 18TH OCTOBER, 2014

OCCUPATIONAL AND ENVIRONMENTAL RISK FACTORS FOR MOTOR NEURONE DISEASE IN NZ

Case - Control Study

OCCUPATIONAL AND ENVIRONMENTAL RISK FACTORS FOR MOTOR NEURON DISEASE

Very little is known about the causes of Motor Neurone Disease. Our study is to investigate the relationship between MND in New Zealand and a range of known or suspected occupational and environmental exposures.


This will be the first New Zealand study to investigate these potential risk factors, and it will allow comparisons to be made with MND in other developed countries.

WHAT IS MOTOR NEURON DISEASE

The motor neuron diseases (MNDs) are a group of progressive neurological disorders that destroy motor neurons, the cells that control essential voluntary muscle activity such as upper and lower limb activities, speaking, breathing, and swallowing.


BACKGROUND AND EPIDEMIOLOGY OF MND

• MND is uncommon but not rare and there is no cure or standard treatment for MND.

• Death usually results from respiratory failure and other lung complications, on average about 3 years after the first symptoms of weakness appear.

• Most MND cases are sporadic, familial ( inherited ) forms of MND account for less than 10% of cases.



• Highest incidence at age 70 years

• MND is more common in males than females with a ratio of 3:2.

• There has been some evidence of increasing incidence and mortality rates in developed countries in the last two decades.



In New Zealand

• 300 cases in NZ at any one time (7/100,000 pa)

• 100 new cases each year (2/100,000 pa)

• Some evidence of increasing incidence in New Zealand

• Ageing population in NZ

(New Zealand has an ageing population, with the proportion aged 65

years or older increasing from 11.8% to 13.1% during 2000- 2010)

The ageing population and increasing incidence mean that the number of MND cases in New Zealand is expected to rise.


POTENTIAL OCCUPATIONAL AND ENVIRONMENTAL RISK FACTORS FOR MND

Occupational risk factors:

• Agricultural chemicals• Electrical occupations/Electromagnetic fields (EMF)/ Electric shock

• Neurotoxic agents : solvents， lead, mercury or other heavy metals

• Welding

• Fumigants : methyl bromide• A range of chemicals in occupations: textile workers, veterinarians,

hairdressers• Military service


POTENTIAL OCCUPATIONAL AND ENVIRONMENTAL RISK FACTORS FOR MND

Environmental and other risk factors:

• Rural vs. urban residence

• Smoking

• Head trauma (history of head injury including sporting injuries)


INTERNATIONAL STUDY - 1- Pesticide exposure and MND

A meta-analysis of epidemiological studies. Malek et al, 2012.

• A meta-analysis of 6 epidemiological studies published to 2011.

• Total 592 cases from 6 studies

Result:

exposure to pesticides had a risk of develop MND

Summary OR=1.88, (95% CI 1.36 – 2.61)


INTERNATIONAL STUDY - 2 - Chemical exposures and ALS

American Cohort study: Weisskopf et al, 2009

• over 1 million participants from American Cancer Society's Cancer Prevention Study II. • Follow-up from 1989 through 2004• Individuals exposed to pesticides/herbicides compared to the unexposed• identified 617 male and 539 female deaths from ALS

Result

*There was a strongly dose-response relation with increasing years of exposure .


Exposures RRPesticides/herbicides(excluding those with missing duration of pesticides exposure )

1.44 ( 95% CI: 0.89-2.31)

Formaldehyde 1.34 ( 95% CI: 0.93-1.92)

INTERNATIONAL STUDY - 3Workplace exposure and ALS

American case control study, Fang, et al ,2009

• 109 cases and 253 control (3 years)• Compare detailed occupation and workplace exposure

Result:


Occupation OR (95% CI)Precision metal workers 3.5 (1.2-10.5)Construction workers 2.9 (1.2-7.2)

INTERNATIONAL STUDY - 3Workplace exposure and ALS continue…

Self-reported exposures to :• paint strippers; • cooling, lubricating oils;• antifreeze or coolants; • mineral or white spirits; • dry cleaning agents

each exposure appeared to be associated with a 60–90% higher risk.


INTERNATIONAL STUDY – 4Head injury and ALS

Oxford Record Linkage Study Turner et al, 2010.• hospital records 1963 - 1999.• Follow up all in-patients for head injury.

ALS rate after head injury RR=1.5 (95% CI 1.1 – 2.1).

Swedish Case and control study, Peters et al, 2013.

4004 Swedish cases and 20,020 controls.

Conclusions: Similar finding of elevated ALS risk with severe head injury.


INTERNATIONAL STUDY – 5Smoking, alcohol consumption, and the risk of MND


Dutch Case-Control study. De Jong et al, 2012494 cases, 1,599 controls.

Results:Current smokers OR = 1.38, 95% CI 1.02 – 1.88.Current smoking also associated with shorter survival

HR = 1.51, 95% CI 1.07 – 2.15.(HR= hazard risk)Current alcohol consumption is a protected factor. OR = 0.52, 95% CI 0.40 – 0.75.

Conclusions: - Current smoking increases risk. - Alcohol consumption reduces risk


“If MND had just one cause, researchers would have found it a long time ago”.

Dr Brian DickieDirector of Research DevelopmentUK MND Association

NEW ZEALAND POPULATION BASED CASE-CONTROL STUDY

The study will recruit 400 cases and 800 controls.

Cases will be diagnosed for MND by neurologists and will be recruited directly from the Motor Neuron Disease Association New Zealand (MNDANZ) and/or neurologists throughout the country.

Controls will be selected from the New Zealand Electoral Roll, with two controls for each case, matched for age and gender. The controls will thus be representative of the general population that generated the cases.



The methods used to collect the data will be the same for both cases and controls

• face-to-face interviews• telephone interviews• postal questionnaires

(depending on the preference of the participant).



Standard questionnaire (16 parts) to obtain information on:

– demographic details– residential history– lifestyle factors– complete occupational history– Agriculture questions



Occupational exposure determined through use of Job Exposure Matrices

Environmental exposure determined through EPA data on location of use of specific chemicals - linked to information on residence.



Result to dateFor cases: • 217 invitation letters have been sent. • 199 replied (92%).• Of those 199, 176 agreed to take part in the study• 164 have been interviewed, 12 cases are in progress

For Controls:• 1600 invitation letters have been sent out, • 814 replied (51%). • Of those 814, 392 participated in the study.• 245 have been interviewed, 147 are in progress.


DETAILS OF CASES

Total cases :176

112 Males

64 Females

Male/Female ratio 3:2

Age group:

• 107 cases (61%) are in the age 60 -74 30 cases (17%) are in the age 60-64 44 cases (25%) are in the age 65-69 33 cases ( 19%) are in the age 70-74

• 11 cases are over 80 • 3 cases are under 40


CASES AGE GROUPS

Age <40

41-49 50-54 55-59 60-64 65-69 70-74 75-79 Age >80

0%

5%

10%

15%

20%

25%

CASES ACCORDING TO DHB

CASES ACCORDING TO DHB


DHBCompleted interviewed

Interviews are in progress

DHBCompleted interviewed

Interviews are in progress

Northland 9 1 Waitemata 8Auckland 12 3 Counties Manukau 4

Bay of Plenty 10 Tairawhiti 1Taranaki 2 Hawke’s Bay 3 1Wanganui 1 MidCentral 6Hutt Valley 4 Capital and Coast 19Wairarapa 2 Nelson Marlborough 11West Coast 3 Canterbury 20 4South Canterbury 6 1 Otago 5Southland 4 Southern 10

74 5 90 7

Total 164 12

2Waikato 21 Lakes 3




Thank you for all your support

Documents

GRACE CHEN18 TH OCTOBER, 2014. OCCUPATIONAL AND ENVIRONMENTAL RISK FACTORS FOR MOTOR NEURONE DISEASE IN NZ Case - Control Study