Elevated Exposure to Lead, Mercury, or Chromium in Relation to Polycystic Ovary Syndrome: A Meta Analysis.
OBJECTIVES This study aims to systematically assess the association between exposure to endocrine-disrupting heavy metals (Pb, Hg, or Cr) and the risk of polycystic ovary syndrome (PCOS) through a meta-analysis of observational studies. DESIGN Meta analysis Materials, Setting, Methods: We thoroughly explored PubMed, Embase, and the Cochrane Library for studies released until April 2023, using MeSH terms and keywords related to heavy metals and PCOS. Inclusion criteria encompassed observational studies reporting blood or urinary concentrations of Pb, Hg, or Cr in PCOS cases versus healthy controls. RESULTS Seven Asian studies involving 897 reproductive-aged women were included. Whole-blood levels of Pb were significantly higher in PCOS (SMD=0.494, 95% CI: 0.227-0.761, p = 0.0003; I² = 99%), while serum or urinary levels showed no difference. Whole blood analysis provided more biologically relevant data for Pb exposure assessment due to its high binding affinity for hemoglobin. No statistically significant associations were observed for Hg exposure across biological matrices: serum (SMD = 2.047, 95% CI: -2.382 to 6.476, p = 0.365), whole blood (SMD = 0.831, 95% CI: -0.740 to 2.401, p = 0.300), or urine (SMD = 0.110, 95% CI: -0.253 to 0.473, p = 0.553). PCOS women had significant increased Cr across biological matrices (serum: SMD=0.287, 95%CI: 0.085-0.632, p <0.001; whole blood: SMD=0.506, 95% CI: 0.184-0.828, p =0.002) with minimal heterogeneity (I² = 0%). CONCLUSIONS This meta-analysis identifies Pb and Cr exposure as a potential risk factor for PCOS in Asian populations. In contrast, Hg exhibited no statistically significant associations. These findings highlight the need for metal-specific prevention strategies in reproductive health.