Platinum Priority – EditorialReferring to the article published on pp. 79–95 of this issue

Incontinence: Do We Speak the Same Language?

Piotr Radziszewski *, Bartosz Dybowski

Department of General, Oncological and Functional Urology, Medical University of Warsaw, Warsaw, Poland

The prevalence of urinary incontinence (UI) has been

studied for years using proper epidemiological methodolo-

gy and large populations. Despite all those efforts, reviews

such as the recent International Consultation on Continence

still have the same conclusion: ‘‘Current data provide very

disparate estimates of population prevalence for UI in

women’’ [1]. In the current issue of European Urology,

Milsom at al present their systematic review on the

prevalence of urgency UI (UUI) [2]. They mention some of

the possible reasons for variations in prevalence: age

distribution, different types of answers given to questions,

and different ways of questionnaire administration. Yet

the authors do not reject the assumption that for some

differences, race, ethnicity, or genetics may be responsi-

ble. Nonetheless, the range of values presented in the

paper is so huge that the reader may be left with the

feeling that we still know nothing about UUI epidemiolo-

gy. This is not true.

UUI is defined as a report of involuntary loss of urine

associated with urgency. This definition is well accepted

and remains the basis for preparing questions used in

surveys. However, the definition is so general that it might

be interpreted in different ways. The definition needs

extension by additional questions on severity, frequency,

and bother. Debate seems to be unresolved on whether we

need total UUI prevalence or bothersome UUI prevalence.

Also, the word urgency is sometimes difficult to translate

into different languages. The same problem might apply to

the questionnaires, as only some of them were culturally

and linguistically validated (for review, see Staskin et al.

[1]). Multinational epidemiological studies often use

nonvalidated definitions and questionnaires, thus produc-

ing severe methodological bias at the very beginning.

Among studies reporting on >5000 respondents cited in

the Milsom et al. review [2], the lowest UUI prevalence in

women was found in the studies originating from Nigeria

(1.6%) [3] and China (1.8%) [4]. Both studies are well

designed. Both research teams proposed their explanations

of low prevalence. Wang et al. [4] stressed the role of

frequency of symptoms (at least once a week), while

Ojengbede et al. [3] pointed at cultural factors such as

reluctance to talk about embarrassing symptoms by some

African communities. Linguistic difficulties also might be

suspected. In China, there are seven main Chinese

languages, each consisting of many dialects, in addition

to languages of national minorities. Yoruba, the language in

Nigeria used in the study by Ojengbede et al. [3], also

consists of almost 20 dialects. Other Chinese studies

reported a much higher UUI prevalence (10–15%), indicat-

ing that it is the UUI definition that probably had the most

effect on the results.

A number of studies reported on UI prevalence stratified

by race. In the National Overactive Bladder Evaluation

(NOBLE) study, the difference between white women and

women of other races was 30%, but this value was neither

significant nor adjusted for other parameters such as body

mass index, income, or education [5]. Important data came

from the Epidemiology of LUTS (EpiLUTS) survey [6].

Logistic regression analysis did not show a significant

difference in the overactive bladder (OAB) prevalence

between races among women. UUI, being a severe grade

of OAB, is not supposed to behave differently. The EPI study

included similar numbers of white and black women [7].

The prevalence of UUI occurring ‘‘often’’ was 7% and 9.8% for

black and white Americans, respectively, aged 35–64 yr.

There is also no proof in the literature of differences related

E U R O P E A N U R O L O G Y 6 5 ( 2 0 1 4 ) 9 6 – 9 8

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DOI of original article: http://dx.doi.org/10.1016/j.eururo.2013.08.031.* Corresponding author. Department of General, Oncological and Functional Urology, Medical University of Warsaw, Lindley’a 4, 02-005 Warsaw,Poland. Tel. +48 225021702; Fax: +48 225022148.E-mail address: pradziszewski@wum.edu.pl (P. Radziszewski).

0302-2838/$ – see back matter # 2013 Published by Elsevier B.V. on behalf of European Association of Urology.http://dx.doi.org/10.1016/j.eururo.2013.09.008

to lifestyle, diet, physical activity, type of work, or toileting

behaviors.

The EPIC and EpiLUTS studies have often been compared

because those two studies, which included populations in

Western Europe and northern America, yielded results so

different that assessment of all the factors discussed

previously seems futile. An in-depth look at methodology

can explain the differences (Table 1) [8,9].

The sample matching adopted in EpiLUTS reduced

selection bias caused by Internet use. However, the sample

matching was not able to adjust for the presumably lower

percentage of UI among nonresponders. In neither of the

two studies has nonresponse bias been addressed. Mean-

while, a couple of approaches are available to assess the

source of variations and to deal with that crucial problem.

However, this large difference in prevalence is most likely

because of the types of answers to the question on UUI

presence and to the use of questions rating UI-related

bother. We are not sure how women with minimal UI

answered the UUI question in the EPIC study. The EpiLUTS

questionnaire design tended to report even the lightest

forms of UI. It is interesting that the prevalence of UUI

causing at least moderate problems in EpiLUTS is quite close

to that reported in EPIC for the same age group. Similar

mechanisms may explain why various prevalence values

are reported by different studies for the same country.

With thousands of people investigated, we should expect

that the topic of UUI prevalence is well studied. With no

reliable proof of significant interracial or international

variations, we just have to accept the best-quality data we

have: data coming from studies with clearly defined

questions and answers; data assessing not only presence

but also frequency, severity, and bother; data from studies

with a high response rate; data from studies performed in a

culture that is open to talk about illness; and data from

studies using validated definitions and questionnaires.

What about the Norwegian Epidemiology of Incontinence

in the County of Nord-Trøndelag (EPINCONT) Study? This

population-based study is characterized by a very high

response rate, reaching 70% among women 40–69 yr [10].

The study assessed UI type, frequency, and severity, as well as

UI-related bother. In the age group 40–69 yr, UUI prevalence

was estimated to be 12%. What we would like to know is

the proportion of those women for whom UUI is at least

‘‘some bother.’’ Looking at the effect of bother on prevalence

presented in EpiLUTS, one can expect values between 4%

and 6%.

So, do we speak the same language? Yes, we do. Can we

be more specific on UUI prevalence? Yes, because we know

a lot. Can we get even more precise data? Yes, if we really

need them.

Conflicts of interest: The authors have nothing to disclose.

References

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Table 1 – Comparison of methods and results between two multinational epidemiologic studies

EPIC [8] EpiLUTS [9]

Population European plus North American

Age, yr �18 (31% <40) �40

Exclusion criteria Infection, pregnancy

Type of study Population-based, cross-sectional

Mode of survey Computer-assisted telephone interview Internet survey

Questionnaire Developed by experts, tested and

improved after pilot studies

Developed, translated, and revised by experts

and users; improved after pilot interviews

Question/answer on UUI Do you leak urine in connection with

a sudden, compelling desire to urinate?

Answer: yes/no

Do you leak urine in connection with

a sudden need to rush to urinate?

Answer: Likert scale

Quantification of frequency No Yes

Assessment of bother No Yes

Response rate, % 33 Sweden: 52.3; USA: 59.6; UK: 60.6

UUI plus mixed UI

crude prevalence, %

Total in women: 3.9; women �40 yr: 5.5 Total in women within past 4 wk: 30.4;

UUI causing minor, moderate, severe, or very severe

problems (excluding no or very minor problems): 16.8;

UUI causing moderate or more severe

problems: 9.5

EpiLUTS = Epidemiology of LUTS; UUI = urgency urinary incontinence; UI = urinary incontinence.

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urinary incontinence, overactive bladder, and other lower urinary

tract symptoms in five countries: results of the EPIC study. Eur Urol

2006;50:1306–15.

[9] Coyne KS, Kvasz M, Ireland AM, Milsom I, Kopp ZS, Chapple CR.

Urinary incontinence and its relationship to mental health and

health-related quality of life in men and women in Sweden, the

United Kingdom, and the United States. Eur Urol 2012;61:88–95.

[10] Hannestad YS, Rortveit G, Sandvik H, Hunskaar S. A community-

based epidemiological survey of female urinary incontinence: the

Norwegian EPINCONT study: Epidemiology of Incontinence in the

County of Nord-Trondelag. J Clin Epidemiol 2000;53:1150–7.

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