Causal relationship between vitamin D and stress urinary incontinence: Two-sample Mendelian randomization study

Observational studies have found an association between vitamin D and stress urinary incontinence (SUI); however, this conclusion remains controversial, and the causal relationship is unclear. This study aimed to investigate the causal relationship between vitamin D and SUI using a Mendelian randomization (MR) approach. We conducted an MR analysis utilizing publicly available summary data from genome-wide association studies on European ancestry for SUI, vitamin D levels, vitamin D supplementation, and vitamin D deficiency. Regression models such as the inverse variance-weighted (IVW) method, MR-Egger, weighted median, and weighted mode were used for analysis, along with heterogeneity tests, sensitivity analyses, and pleiotropy assessments.MR analysis indicated that vitamin D levels, vitamin D deficiency, and vitamin D supplementation were not causally associated with SUI (IVW OR: 0.999, 95% CI: 0.992-1.006, P = .786); (IVW OR: 1.000, 95% CI: 1.000-1.000, P = .646); (IVW OR: 1.000, 95% CI: 1.000-1.001, P = .064). No evidence of horizontal pleiotropy or heterogeneity was found (P > .05). Our findings do not support a causal relationship between vitamin D and SUI. The incidental effect of SUI and vitamin D may be mediated by other factors, warranting further observational studies and clinical trials.