Urinary incontinence and hydration: A population-based analysis

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.

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).

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.

Hydration status as defined by urine osmolality was not associated with moderate to severe urinary incontinence in men or women.