Effect of vitamin D supplementation on the severity of stress urinary incontinence in premenopausal women with vitamin D insufficiency: a randomized controlled clinical trial

BACKGROUND: Urinary incontinence, especially stress urinary incontinence (SUI), is one of the problems experienced by premenopausal women. Given the role of vitamin D in enhancing muscle strength and function, this study explored the effect of vitamin D3 supplementation on SUI in premenopausal women. METHODS: A randomized controlled trial was performed with 60 premenopausal women referring to Kerman gynecological clinic in 2020 and 2021. Eligible women received a 5000-unit vitamin D supplement or placebo weekly for 3 months. The International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form (ICIQ-SF) was utilized to assess SUI severity before and after the intervention. The t-test, Chi-square test, and repeated measures ANOVA were carried out in SPSS software (version 22) to analyze the data. P-values smaller than 0.05 were considered significant. RESULTS: Before the intervention, there was no significant difference between the intervention and control groups in SUI severity (P = 0.652) and the impact of SUI severity on premenopausal women’s lives (P = 0.804). In contrast, after 8-12 weeks of vitamin D supplementation, these scores decreased significantly in the intervention group relative to the control group (P < 0.001). In addition, after vitamin D supplementation, the number of SUI and urinary leakage symptoms decreased in the intervention group (P < 0.001). CONCLUSION: Vitamin D supplementation improves SUI in premenopausal women. TRIAL REGISTRATION: This trial was registered with the Iranian Registry of Clinical Trials; https://fa.irct.ir/trial/53474 (IRCT20190724044318N2) on 11/02/2021.