Effectiveness of vitamin D supplementation on lipid profile in polycystic ovary syndrome women: a meta-analysis of randomized controlled trials

BACKGROUND Vitamin D deficiency (VDD) is prevalent in polycystic ovary syndrome (PCOS) and the relationship between dyslipidemia and vitamin D status is close. This meta-analysis was to evaluate the effect of vitamin D (alone or with co-supplementation) on lipid profile in PCOS patients. METHODS Medline, the Cochrane Library, PubMed, and Web of Science were searched, and randomized controlled trials (RCTs) published prior to January, 2020 were identified. The pooled estimates of standardized mean deviation (SMD) with 95% confidence intervals (CI) were calculated using a fixed effect model or random effect model. RESULTS A total of 954 identified studies were retrieved, and 11 RCTs involving 677 participants were ultimately included in the meta-analysis. The pooled results suggested an association between vitamin D supplementation and a reduction in total cholesterol (TC) concentrations (SMD: -0.36 mg/dL, 95% CI: -0.54 to -0.18 mg/dL, P<0.0001), triglycerides (TG) (SMD: -0.50 mg/dL, 95% CI: -0.68 to -0.32 mg/dL, P<0.00001), low-density lipoprotein cholesterol (LDL-C) (SMD: -0.28 mg/dL, 95% CI: -0.45 to -0.11 mg/dL, P=0.001), and very low-density lipoprotein cholesterol (VLDL-C) (SMD: -0.54 mg/dL, 95% CI: -0.74 to -0.35 mg/dL, P<0.00001), but no effect on high-density lipoprotein cholesterol (HDL-C) (SMD: 0.01 mg/dL, 95% CI: -0.16 to 0.18 mg/dL, P=0.89) was found. Subgroup analyses showed that the dosage of vitamin D used, the duration of intervention and the type of vitamin D supplementation (alone or with co-supplementation) might influence the effect of vitamin D on the lipid profile. CONCLUSIONS This meta-analysis demonstrated that PCOS patients with the therapy of vitamin D had a statistical improvement in TC, TG, LDL-C, and VLDL-C, but did not affect HDL-C concentrations.