Vitamin D intake and the 10-year risk of urgency urinary incontinence in women.

Evidence indicates that higher serum 25-hydroxy vitamin D levels may be associated with decreased prevalence of urgency urinary incontinence (UI), but the impact of vitamin D consumption on development of urgency and mixed UI is unclear. The objective was to assess whether greater vitamin D intake was associated with decreased risk of incident urgency and mixed UI over 10 years using 2 large prospective cohorts of middle-aged and older women. We analyzed 38,101 women from the Nurses' Health Study I (NHS I) and 35,190 women from NHS II who were free of UI at baseline. We followed incident UI, defined as new UI occurring at least monthly, separately by subtype (urgency, mixed, stress UI), from 2002-2012. We categorized vitamin D intake from supplements and diet. We estimated relative risk for developing UI according to vitamin D intake using Cox-proportional hazard models with adjustment for covariates. Median vitamin D intake was 580IU in the older women in NHS I (age range 56-71 at baseline) and 487IU in middle-aged women in NHS II (age range 40-57). Among women taking ≥1000IU of vitamin D, median intake in the older women was 1252IU and 1202IU in the middle-aged women. Among the older women, we found no relation of vitamin D intake to risk of developing UI, across all UI subtypes. In multivariable-adjusted analysis for middle-aged women, the relative risk of developing mixed UI among women taking >1000IU was 0.79 (0.63, 0.99) and for urgency UI was 0.88 (0.71, 1.07), versus <200IU. Risks of developing stress UI were not related to vitamin D intake categories. Overall, we did not find a relationship between vitamin D intake and UI incidence in middle-aged and older women; however, the reported intake was moderate.