The effect of Vitamin D supplementation on hormonal and glycaemic profile of patients with PCOS: A meta-analysis of randomised trials

Background: Vitamin D deficiency is frequently manifested in women with polycystic ovarian syndrome (PCOS). To date, supplementation of deficient patients has not been correlated with the hormonal and metabolic status of these patients. Purpose: We aimed to investigate the impact of vitamin D supplementation on the hormonal and metabolic profile of PCOS women. Materials and Methods: We searched Medline, Scopus, ClinicalTrials.gov and Cochrane Central Register databases for published randomised controlled trials. The meta-analysis was performed with the RevMan 5.3.5 software. Results: Nine studies were included in the present meta-analysis which investigated the impact of vitamin D supplementation in 647 patients. According to our meta-analysis neither serum testosterone (MD 0.04 ng/mL, 95% CI -0.09 to 0.17) nor serum LH (MD -0.48 IU/mL, 95% CI -1.97 to 1.00) were significantly affected by vitamin D supplementation in any of the subgroup comparisons. On the contrary, serum DHEAS was significantly affected by vitamin D (MD -32.24 mu g/dL, 95% CI -32.24 to -14.01) an effect which was mainly affected by the vitamin D vs placebo comparison. Vitamin D supplementation did not have an impact on fasting glucose (MD 0.42 mg/dL, 95% CI -2.75 to 3.60) or fasting insulin (MD 1.27 mu U/mL, 95% CI -1.42 to 3.97) levels. HOMA-IR was, however, increased among patients that received placebo compared to vitamin D (MD 0.52, 95% CI 0.39-0.65). Conclusion: There is no evidence to support that vitamin D supplementation significantly benefits PCOS patients. However, given the relatively small number of enrolled patients further studies are needed to elucidate this field.