Association between Ambient Air Pollution and Diabetes Mellitus: Systematic Review and Meta-Analysis

Background: Air pollution is hypothesized to be a risk factor for diabetes mellitus. Epidemiological evidence is inconsistent and has not been systematically evaluated. Objectives: We systematically reviewed epidemiological evidence on the association between air pollution and diabetes, and synthesized results of studies on type 2 diabetes (T2DM). Methods: We systematically searched epidemiological studies reporting the association between air pollution (particle concentration or traffic exposure) and diabetes (type 1, type 2 or gestational) in electronic literature databases up to 03 February 2014. We systematically evaluated risk of bias and role of potential confounders in all studies. We synthesized results of the association with T2DM in meta-analyses using random effect models and conducted several sensitivity analyses. Results: We included 12 studies (eight on T2DM, two on type 1, two on gestational diabetes). All were conducted in Europe or North-America. Five studies had a longitudinal design, fo...