Association of stress urinary incontinence with serum 25-hydroxyvitamin D level in adult women: A cross-sectional analysis of the National Health and Nutrition Examination Survey (2005-2018) data.

ObjectiveTo examine the association between serum 25-hydroxyvitamin D levels and stress urinary incontinence among women in the United States.MethodsThis cross-sectional analysis included data from 13,768 female participants of the National Health and Nutrition Examination Survey (2005-2018). Weighted multivariable logistic regression, subgroup analyses, and restricted cubic spline analysis were used to evaluate associations.ResultsOverall, 42% of the participants had stress urinary incontinence. In fully adjusted models, continuous serum 25-hydroxyvitamin D level was inversely associated with stress urinary incontinence (odds ratio = 0.98, 95% confidence interval: 0.96-1.00, p = 0.040). The highest quartile (fourth quartile, Q4) of 25-hydroxyvitamin D level also showed a significant inverse association with stress urinary incontinence (odds ratio = 0.81, 95% confidence interval: 0.68-0.96, p = 0.016). A significant interaction with smoking status was detected (p < 0.001). Restricted cubic splines revealed a nonlinear relationship (p-nonlinear = 0.012) with a threshold level of 73.8 nmol/L, and 25-hydroxyvitamin D levels beyond this value were associated with a reduced risk of stress urinary incontinence.ConclusionHigher 25-hydroxyvitamin D levels (≥73.8 nmol/L) are associated with a lower risk of stress urinary incontinence among women in the United States, indicating a nonlinear relationship. Further prospective studies are needed to confirm these findings.