Associations between Air Pollution Indicators and Prevalent and Incident Diabetes among African American Participants in the Jackson Heart Study
Type 2 diabetes mellitus (DM) is a major risk factor for cardiovascular disease (CVD) and is especially prevalent among African Americans. Prior studies suggest that long-term exposure to ambient air pollution is may be associated with greater incidence of DM, but results remain heterogeneous and few studies have included large numbers of African Americans. We assessed DM status among African American participants of the Jackson Heart Study, an ongoing prospective cohort study, at visit 1 (2000-2004, N = 5231) and visit 2 (2005-2008, N = 2845). We estimated residential levels of 1-year and 3-year fine particulate matter (PM2.5) and ozone (O3). We used mixed-effect modified Poisson regression to estimate prevalence ratios (PR) and 95% confidence intervals (CI) of the association between markers of air pollution exposure and prevalent DM at visits 1 and 2, and risk ratios (RR) of indicators of air pollution exposure at visit 1 and cumulative incidence of DM at visit 2. We adjusted for potential confounding by patient characteristics and comorbid conditions, as well as inverse probability weights of DM at visit 2 and accounting for clustering by census tract. We did not observe associations between 1-year or 3-year PM2.5 and incident or prevalent DM. We observed a positive association between 1-year O3 and incident DM at visit 2 (RR = 1.12, 95% CI 1.04, 1.20). Our results provide some evidence of possible positive associations between indicators of long-term O3 exposure and DM. However, we did not observe associations with PM2.5. This study is particularly relevant to African Americans, who have higher prevalence of DM but relatively few studies of environmental pollution risk factors.