Endocrine‐disrupting chemicals, risk of type 2 diabetes, and diabetes‐related metabolic traits: A systematic review and meta‐analysis

Abstract Background Elevated blood or urinary concentrations of endocrine‐disrupting chemicals ( EDCs ) may be related to increased risk of type 2 diabetes ( T2D ). The aim of the present study was to assess the role of EDCs in affecting risk of T2D and related metabolic traits. Methods MEDLINE was searched for cross‐sectional and prospective studies published before 8 M arch 2014 into the association between EDCs (dioxin, polychlorinated biphenyl [ PCB ], chlorinated pesticide, bisphenol A [ BPA ], phthalate) and T2D and related metabolic traits. Three investigators independently extracted information on study design, participant characteristics, EDC types and concentrations, and association measures. Results Forty‐one cross‐sectional and eight prospective studies from ethnically diverse populations were included in the analysis. Serum concentrations of dioxins, PCBs , and chlorinated pesticides were significantly associated with T2D risk; comparing the highest to lowest concentration category, the pooled relative risks ( RR ) were 1.91 (95% confidence interval [ CI ] 1.44–2.54) for dioxins, 2.39 (95% CI 1.86–3.08) for total PCBs , and 2.30 (95% CI 1.81–2.93) for chlorinated pesticides. Urinary concentrations of BPA and phthalates were also associated with T2D risk; comparing the highest to lowest concentration categories, the pooled RR were 1.45 (95% CI 1.13–1.87) for BPA and 1.48 (95% CI 0.98–2.25) for phthalates. Further, EDC concentrations were associated with indicators of impaired fasting glucose and insulin resistance. Conclusions Persistent and non‐persistent EDCs may affect the risk of T2D . There is an urgent need for further investigation of EDCs , especially non‐persistent ones, and T2D risk in large prospective studies.