Effect of vitamin D on biochemical parameters in polycystic ovary syndrome women: a meta-analysis

Aim To investigate the therapeutical effect of vitamin D supplementation on the metabolism and endocrine parameters of PCOS patients. Materials and methods Clinical studies investigating the therapeutic effect of vitamin D supplementation on PCOS patients were selected by searching PubMed, Embase, The Cochrane library and Web of Science until April 2016. The included articles were selected according to the inclusion criteria. Serum HOMA-IR, QUICKI, LDL, DHEAS, free testosterone (FT), total testosterone (TT), PTH, 25-hydroxy-vitamin D, and triglyceride of PCOS patients were enrolled for evaluating the therapeutic effects of vitamin D. Results 16 studies were included in this study. There was no significant difference between the placebo group and vitamin D group in the concentration of serum 25-hydroxyvitamin D in patients with PCOS (P = 0.06). After treated with vitamin D, the serum 25-hydroxy- vitamin D in PCOS patients was increased (P < 0.00001), while the serum PTH (P = 0.003) and triglyceride (P = 0.006) were decreased. In addition, the serum HOMA-IR, QUICKI, LDL, DHEAS, FT, and TT in PCOS patients did not change. Subgroup analysis showed that the serum triglyceride of PCOS patients was decreased by low dose of vitamin D supplementation (< 50,000 IU) ( P = 0.03), but no significantly changed by high-dose vitamin D supplementation (C50,000 IU) (P = 0.17). Conclusion Vitamin D supplementation significantly attenuates serum PTH and triglyceride in PCOS patients except for serum HOMA-IR, QUICKI, LDL, DHEAS, FT, and TT. Furthermore, less than 50,000 IU vitamin D supplementation is sufficient for decreasing serum triglyceride.