Vitamin D and stress urinary incontinence in pregnancy: a cross-sectional study

Abstract

Objective To assess the association between levels of vitamin D and urinary incontinence (UI) in pregnancy. Design A cross‐sectional study. Secondary analysis of a randomised controlled trial. Setting Two university hospitals in Norway. Population A total of 851 healthy, pregnant women >18 years in gestational weeks 18–22 with a singleton live fetus. Methods Data on UI were collected from a questionnaire at inclusion and serum analysis of 25‐hydroxy vitamin D (25(OH)D) was performed. Univariable and multivariable logistic regression analyses were applied to study associations between exposure and outcomes. Main outcome measures Prevalence of self‐reported UI, stress (SUI) and urge (UUI) or mixed UI. Results In total, 230/851 (27%) of the participants were vitamin D insufficient (25(OH)D <50 nmol/l) and 42% reported to have any UI. Women with 25(OH)D <50 nmol/l were more likely to report any UI (P = 0.03) and SUI (P < 0.01) compared with women with 25(OH)D ≥50 nmol/l. In a univariable logistic regression analysis, serum levels of 25(OH)D <50 nmol/l was associated with increased risk of any UI (odds ratio [OR] 1.5 with 95% CI 1.0–2.1), SUI only (OR 1.7, 95% CI 1.2–2.4), but not mixed UI or UUI only (OR 0.8, 95% CI 0.5–1.5). In a multivariable logistic regression model, serum levels of 25(OH)D <50 nmol/l were associated with a higher risk of experiencing SUI only (OR 1.5, 95% CI 1.1–2.2). Conclusions Serum 25(OH)D <50 nmol/l was associated with increased risk of any UI, and SUI in particular.