Body mass index and adult female urinary incontinence.

The aim of the present investigation was to study the possible role of obesity in the etiology of adult female urinary incontinence (UI). A random population sample of 3,114 women aged 30-59 years were mailed a questionnaire concerning UI and, among other things, body weight and height. The overall rate of response was 85%, and the present analysis comprises 2,589 women who supplied information about their body weight and height. The period prevalence of all UI, stress UI, urge UI, and mixed stress and urge UI was 17%, 15%, 9%, and 7%, respectively. The mean body mass index (BMI) was 22.7 kg/m2. Irrespective of other risk indicators, BMI was positively associated with UI prevalence (OR, 1.07/BMI unit; P < 0.0001). BMI interacted with childbirth in predicting stress UI prevalence, with cystitis in predicting urge UI, and with both in predicting mixed UI. Stress UI proved to be the UI type most closely associated with BMI.