Effects of vitamin D supplementation on metabolic parameters of women with polycystic ovary syndrome: a meta-analysis of randomized controlled trials

The purpose of this meta-analysis was to evaluate the effects of vitamin D supplementation on metabolic parameters of women with polycystic ovary syndrome (PCOS). We performed a literature search of databases and identified randomized controlled trials (RCTs) published prior to December 2019. A meta-analysis was conducted using RevMan 5.3 and Stata 12.0 software. We compared the effects of vitamin D supplementation alone to the administration of placebos on metabolic parameters of PCOS women with vitamin D deficiency. Ten articles of RCTs were included and analyzed in this meta-analysis, which included a total of 520 PCOS women. Our meta-analysis results showed no significant effects of vitamin D supplementation on BMI (<i>p</i> = .43), systolic blood pressure (<i>p</i> = .05), diastolic blood pressure (<i>p</i> = .87), fasting insulin concentration (<i>p</i> = .86), HOMA-IR (<i>p</i> = .47), HDL-C (<i>p</i> = .76), LDL-C (<i>p</i> = .23) and triglyceride (<i>p</i> = .77). Both low dose vitamin D supplementation (&lt;4000 IU/day) and high dose vitamin D supplementation (≥4000 IU/day) were found to significantly decreased the fasting glucose concentration (<i>p</i> = .01, <i>p</i> = .001, respectively). Vitamin D supplementation significantly decreased total cholesterol concentration (<i>p</i> = .03). The results of this meta-analysis suggested that vitamin D supplementation decreases fasting glucose concentration and total cholesterol concentration in PCOS women with vitamin D deficiency.