Serum vitamin D levels in females with urinary incontinence: a meta-analysis of observational trials

Introduction and hypothesis The association of vitamin D deficiency with female urinary incontinence is unclear. Methods A systematic review of English and non-English articles was conducted. All observational studies in databases including PubMed, EMBASE, the Cochrane Library Trials Register, and Google Scholar were searched until 5 October 2020. Additional studies were identified by contacting clinical experts and searching the bibliographies and abstracts of the compiled articles. Search terms included urinary incontinence and vitamin D. Article data, including study quality indicators, were independently extracted by two authors using predefined data fields. Results Two cohort studies, four case-control studies and five cross-sectional studies were included in the qualitative synthesis. Two cohort studies and one cross-sectional study, with a total of 2501 females, were included in the meta-analysis. Heterogeneity among the three studies was not observed (I2 = 0.0%, P = 0.69). All pooled analyses were based on fixed-effects models. No difference in vitamin D level was observed between the urinary incontinence group and the control group (mean difference 0.07 ng/ml; 95% confidence interval [CI] –0.57–0.72, P = 0.81, I2 = 0%). Conclusions Our meta-analysis revealed that adult females with urinary incontinence did not have lower serum vitamin D levels than control females.