The Hordaland Women's Cohort: prevalence, incidence, and remission of urinary incontinence in middle-aged women.

INTRODUCTION AND HYPOTHESIS: The aim of study is to prospectively investigate the prevalence, incidence, and remission of urinary incontinence (UI) in a cohort of middle-aged women. METHODS: In 1997-1999, 2,229 randomly selected women aged 41-45 agreed to participate in the Hordaland Women's Cohort, and six almost identical postal questionnaires were sent them during the following 10 years. Response rate was 95.7% at inclusion and has remained 87% to 93% in subsequent waves; 64.1% answered all six questionnaires. UI variables include type, amount, frequency, and severity. RESULTS: Prevalence of UI increased by age until a peak in age group 51-52 years for any (50.3%) and significant (10.0%) UI. There was then a decrease in prevalence caused by a decrease in incidence and decrease in remission. Stress UI was the major type and most UI was of low severity. CONCLUSION: Prevalence of any UI is high in middle-aged women but reaches a peak followed by a decrease.