Purpose: In younger men lower body mass is associated with fewer urinary symptoms, including incontinence and nocturia. However, lower body mass may have different implications in older men due to age associated muscle atrophy and decreased strength.
Materials and methods: We performed a prospective analysis of community dwelling men 70 to 79 years old in the multicenter Health ABC (Aging and Body Composition) study who underwent measurement of body mass on physical examination, composition using dual x-ray absorptiometry and strength according to grip and lower leg dynamometry. We evaluated associations with prevalent incontinence and nocturia on structured questionnaires as well as concurrent changes in urinary symptoms during 3 years using multivariate logistic regression.
Results: Of the 1,298 men analyzed 22% reported incontinence and 52% reported nocturia at baseline. Higher body mass index, fat mass and lower appendicular lean mass, and grip and quadriceps strength corrected for body mass index were associated with an increased prevalence of incontinence (each p <0.05). Higher body mass index and greater fat mass were also associated with an increased nocturia prevalence (each p <0.05). Concurrent 5% or greater decrease in body mass or fat mass was not associated with lower odds of new or worsening incontinence or nocturia, whereas a 5% or greater decrease in maximum grip strength was associated with higher odds of new or worsening incontinence.
Conclusions: Older men with a higher body mass index and greater fat mass are more likely to report prevalent incontinence and nocturia. However, late life decreases in strength but not increases in body mass or fat mass were associated with a concurrent increase in urinary incontinence.
Keywords: body composition; body mass index; lower urinary tract symptoms; muscle strength; urinary bladder.