Abstract
OBJECTIVE: To characterize change in physical performance and differential prevalence of low skeletal muscle mass and strength (sarcopenia) and lower 25-hydroxyvitamin D concentrations among older women who developed urinary incontinence (UI) symptoms. METHODS: This is a secondary analysis of the Health, Aging, and Body Composition Study. Urinary incontinence symptoms were assessed using validated questions. The Short Physical Performance Battery measured physical performance. Sarcopenia, defined by low muscle mass and strength, was determined using validated cutoffs for gait speed, grip strength, and appendicular skeletal muscle mass. All parameters were evaluated at baseline and year 4. Serum 25-hydroxyvitamin D concentrations were assessed at year 2. The primary outcome was change in Short Physical Performance Battery total scores. Sarcopenia and lower serum 25-hydroxyvitamin D concentrations have been independently associated with poor physical performance and UI and were therefore included as secondary outcomes. Univariate and multivariate analyses were used to characterize the associations of change in physical performance from baseline to year 4, incidence of sarcopenia, and lower serum 25-hydroxyvitamin D on the development of UI symptoms. RESULTS: Of the 1,583 women enrolled, 910 were excluded (730 had baseline UI; 180 with missing data). Six hundred seventy-three women were continent at baseline; 223 (33%) developed UI symptoms at year 4. SPPB total scores significantly declined in women with UI versus continent women (mean difference continent-incident UI 0.32, 95% CI 0.04-0.60, P=.02). Of subscale measures, standing balance showed the greatest decline at 0.20 (0.05-0.36; continent-incident UI, respectively; P=.009). Sarcopenia developed at a higher rate with incident UI (adjusted odds ratio [OR] 1.7, 95% CI 1.0-2.9). Low 25-hydroxyvitamin D was not associated with incident UI (adjusted OR 1.1, 95% CI 0.7-1.6 and 1.1, 95% CI 0.7-1.6 for deficient or insufficient versus sufficient status, respectively). CONCLUSION: We observed a significant decline in standing balance among older women who developed UI symptoms. This decline may be associated with coinciding development of sarcopenia.