Vitamin D and Urinary Incontinence among Korean Women: a Propensity Score-matched Analysis from the 2008–2009 Korean National Health and Nutrition Examination Survey

A recent study investigated the role of vitamin D in urinary incontinence (UI). However, very few data are available on this topic. Therefore, we evaluated these relationships using nationally representative data from Korea. We included 6,451 women over the age of 20 years who had participated in the Korea National Health and Nutrition Examination Survey IV. We conducted a propensity-matched study by identifying women with UI. Women without UI, matched for menopause, number of pregnancies, hypertension, diabetes, body mass index, age, stroke, asthma, and chronic obstructive pulmonary disease, were selected as a control group at a 2:1 ratio. The χ(2) test, t-test and logistic regression analyses were used. Following propensity score matching, 558 UI cases and 1,116 normal controls were included, and confounders (menopause, hypertension, diabetes mellitus, asthma, age, obesity, and number of pregnancies) were evenly dispersed and did not differ significantly between the groups. There was no significant difference between the mean vitamin D levels of the UI and normal groups (vitamin D: 18.4 ± 6.6 vs. 18.5 ± 7.0 ng/mL; P = 0.752). Additionally, there was no significant difference in the distribution of vitamin D levels (< 20 ng/mL, 20–30 ng/mL, > 30 ng/mL: 63.8%, 30.5%, and 5.7% in normal controls, 64.0%, 27.8%, and 8.2% in UI cases; P = 0.107). In conclusion, low serum vitamin D is not significantly and independently related to female UI after propensity score matching in representative Korean data.