Objective: To examine the association between physical activity and risk of developing urinary incontinence (UI).
Methods: Prospective analysis from the Nurses' Health Study of women aged 54-79 years. Physical activity was reported in 1986 and biennially afterward. To determine stable, long-term activity levels, data were averaged across all questionnaires (bottom quintile: 6.2 metabolic equivalent task hours per week or less; top quintile: more than 28.6 metabolic equivalent task hours per week). From 2000 to 2002, 2,355 cases of incident UI were identified using self-reports of leaking urine. Type of incontinence was determined from questions regarding the circumstances during which leaking occurred. We estimated adjusted odds ratios (ORs) of developing incontinence across quintiles of physical activity levels using logistic regression, controlling for numerous potential confounding factors.
Results: Increasing levels of total physical activity were significantly associated with a reduced risk of UI (top versus bottom quintile of metabolic equivalent task hours per week, OR 0.81, 95% confidence interval [CI] 0.71-0.93; P for trend across quintiles <.01). Walking, which constituted approximately half of total physical activity among our participants, was related to 26% lower risk of developing UI (top versus bottom quintile, OR 0.74, 95% CI 0.63-0.88; P for trend across quintiles <.01). Specifically, total physical activity and walking were associated with a significant reduction in stress UI (physical activity: P for trend =.01; walking: P for trend =.01), but neither was related to incidence of urge UI (P for trend =.8 and P for trend =.3, respectively).
Conclusion: Physical activity was associated with a significant reduction in UI. Results appeared somewhat stronger for stress UI than urge UI.
Level of evidence: II.