Urinary Incontinence in Older Women: The Role of Body Composition and Muscle Strength: From the Health, Aging, and Body Composition Study

Objectives: To evaluate prospective relationships between body composition and muscle strength with predominantly stress urinary incontinence (SUI) and urgency urinary incontinence (UUI) in older women.

Design: Prospective community-dwelling observational cohort study (Health, Aging, and Body Composition study).

Participants: Women initially aged 70 to 79 recruited from Pittsburgh, Pennsylvania, and Memphis, Tennessee (N = 1,475).

Measurements: Urinary incontinence was assessed using structured questionnaires. Body mass index (BMI), grip strength, quadriceps torque, and walking speed were assessed using physical examination and performance testing. Appendicular lean body mass (ALM) and whole-body fat mass were measured using dual-energy X-ray absorptiometry.

Results: At baseline, 212 (14%) women reported at least monthly predominantly SUI and 233 (16%) at least monthly predominantly UUI. At 3 years, of 1,137 women, 164 (14%) had new or persistent SUI, and 320 (28%) had new or persistent UUI. Women had greater odds of new or persistent SUI if they demonstrated a 5% or greater decrease in grip strength, (adjusted odds ratio (AOR) = 1.60, P = .047) and lower odds of new or persistent SUI if they demonstrated a 5% or greater decrease in BMI (AOR = 0.46, P = .01), a 5% or greater increase in ALM corrected for BMI (AOR = 0.17, P = .004), or a 5% or greater decrease in fat mass (AOR = 0.53, P = .01). Only a 5% or greater increase in walking speed was associated with new or persistent UUI over 3 years (AOR = 1.54, P = .04).

Conclusion: In women aged 70 and older, changes in body composition and grip strength were associated with changes in SUI frequency over time. In contrast, changes in these factors did not influence UUI. Findings suggest that optimization of body composition and muscle strength is more likely to modify risk of SUI than of UUI in older women.