Zinc status and polycystic ovarian syndrome: A systematic review and meta-analysis

Several studies have investigated serum zinc levels in patients with polycystic ovarian syndrome (PCOS), but the results of these studies remain inconclusive. Therefore, to derive a more precise estimation, we conducted a meta-analysis to investigate serum zinc concentrations in women with PCOS in comparison with healthy subjects. Electronic search was performed in PubMed, Scopus, and Google scholar up to April; 4, 2018 without any restriction. Eligible studies that evaluated the levels of zinc status in subjects with PCOS were included. Weighted mean differences (WMDs) with corresponding 95% Cls in serum zinc levels were initially estimated using a random-effects model. Eight studies, measuring circulating zinc levels in 552 PCOS and 464 control subjects, were included. Pooled effect size suggested that serum zinc levels in women with PCOS were not statistically different than their controls (WMD = 4.43 mg/dL; 95% CI = [10.30, 1.44]; P = 0.139). Exclusion of one study revealed that women with PCOS significantly have lower serum zinc levels compared to healthy controls (WMD: 6.60 mg/dL; 95% CI = [-12.43, 0.76], P = 0.027). Our study indicated that circulating zinc levels in women with PCOS were significantly lower than those in healthy controls when detailed analysis is conducted. Large scale studies are needed to elucidate clear relation between zinc status and etiology of PCOS.