Are smoking and other lifestyle factors associated with female urinary incontinence? The Norwegian EPINCONT Study.

Objective: To examine whether modifiable lifestyle factors such as smoking, obesity, physical activity and intake of alcohol or caffeinated drinks were associated with urinary incontinence in women.

Design: Cross sectional population-based study.

Setting: The Norwegian Epidemiology of Incontinence in the County of Nord-Trøndelag (EPINCONT) Study is part of a large survey performed in a county in Norway during 1995-1997.

Population: Women >/=20 years (n = 34,755, 75% of the invited) attended the first part of the survey and received the questionnaire. There were 27,936 (80% of source population) women who completed the incontinence part of the questionnaire.

Methods: Questionnaire covering several health topics including urinary incontinence was received at a screening station. Logistic regression analysis was used to adjust for confounding and to establish associations with the different outcomes under investigation: any incontinence, severe incontinence and stress, urge and mixed subtypes.

Main Outcome Measures: Effect measure were odds ratios with corresponding 95% confidence intervals.

Results: Former and current smoking was associated with incontinence, but only for those who smoked more than 20 cigarettes per day. Severe incontinence was weakly associated with smoking regardless of number of cigarettes. The association between increasing body mass index and incontinence was strong and present for all subtypes. Increasing levels of low intensity physical activity had a weak and negative association with incontinence. Tea drinkers were at slightly higher risk for all types of incontinence. We found no important effects of high intensity physical activity, intake of alcohol or coffee.

Conclusions: Several potentially modifiable lifestyle factors are associated with urinary incontinence. Highest odds ratios were found for body mass index, heavy smoking and tea drinking.