Objectives: To estimate (1) the prevalence of urinary incontinence in a population-based sample of Australian women aged 45-55 and to identify the factors associated with urinary incontinence; (2) the incidence of urinary incontinence over a 7-year follow-up period and to identify whether the transition from pre- to postmenopause is associated with the development of urinary incontinence.
Methods: This was a cross-sectional study of 1897 women and a 7-year longitudinal follow-up of 373 of these women who were premenopausal at baseline. Annual interviews and physical measurements were taken in their homes.
Results: Cross-sectional: the prevalence of urinary incontinence was 15%; multivariate analysis found that urinary incontinence patients were significantly more likely than those without incontinence to have higher body mass index (odds ratio [OR] 1.50, 95% confidence interval [CI] 1.15, 1.95), have had gynecologic surgery (OR 2.17, 95% CI 1.42, 3.32), report urinary tract infections (OR 4.75, 95% CI 2.28, 9.90), diarrhea or constipation (OR 1.95, 95% CI 1.27, 3.00), and have had three or more children (OR 1.47, 95% CI 1.06, 2.05). Longitudinal: during the 7-year follow-up, the average prevalence of urinary incontinence was 18% and the overall incidence 35%. Women who experienced a hysterectomy during the follow-up period had a higher incidence.
Conclusion: Urinary incontinence in middle-aged women is more closely associated with mechanical factors than with menopausal transition.