Urinary incontinence and hydration: A population‐based analysis

Aims To determine if there is an association between urinary incontinence (UI) and an objective measure of hydration status in men and women in a nationwide, population‐based sample. Methods We utilized data from the 2009 to 2010 and 2011 to 2012 National Health and Nutrition Examination Surveys (NHANES), cross sectional surveys of the US non‐institutionalized population. Our primary outcome was moderate/severe UI measured using a validated scale. Our exposure of interest was hydration status. Urine osmolality ≥ 800 mOsm/kg defined dehydration versus adequate hydration (<800 mOsm/kg). We included men and women ≥ 20 years who had both UI and urine osmolality data. Using multivariable models, we controlled for age, race/ethnicity, BMI, chronic kidney disease, the interaction of age with osmolality, and hysterectomy (women only). Results Among the 11 482 total subjects, 9497 (83%—4882 men and 4615 women) had both UI and urine osmolality data. Compared to women, men were less likely to report UI (5.9% vs 18.9%; P < 0.001) and more likely to be dehydrated (33.4% vs 24.0%; P < 0.001). In bivariate analysis, men and women who were dehydrated had less UI than men with adequate hydration (men: 3.5% vs 7.6%; P < 0.001; women: 16.3% vs 20.0%; P = 0.02); however, dehydration was not associated with UI in men (OR 0.2, 95% CI 0.6‐1.0) or in women (OR 0.8, 95% CI 0.4‐1.5) in multivariable models. Conclusions Hydration status as defined by urine osmolality was not associated with moderate to severe urinary incontinence in men or women.