While laboratory studies show that air pollutants can potentiate insulin resistance, the epidemiologic evidence regarding the association of air pollution with diabetes incidence is conflicting. The purpose of the present study was to assess the association of the traffic-related nitrogen dioxide (NO2) with the incidence of diabetes in a longitudinal cohort study of African American women. We used Cox proportional hazards models to calculate hazard ratios and 95% confidence intervals (CI) for diabetes associated with exposure to NO2 among 43,003 participants in the Black Women's Health Study (BWHS). Pollutant levels at participant residential locations were estimated with 1) a land use regression model for participants living in 56 metropolitan areas, and 2) a dispersion model for participants living in 27 of the cities.From 1995 to 2011, 4387 cases of diabetes occurred. The hazard ratios per interquartile range of NO2 (9.7 ppb), adjusted for age, metropolitan area, education, vigorous exercise, body mass index, smoking, and diet, were 0.96 (95% CI 0.88-1.06) using the land use regression model estimates and 0.94 (95% CI 0.80, 1.10) using the dispersion model estimates. The present results do not support the hypothesis that exposure to NO2 contributes to diabetes incidence in African American women.
Bibliographical noteFunding Information:
This study was supported by grants from the National Institute of Environmental Health Sciences ( ES019573 ) and the National Cancer Institute ( UM1CA164974 and CA058420 ). The funding sources had no involvement in study design; collection, analysis, and interpretation of data; writing the paper; or in the decision to submit for publication. The content of this article is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
© 2016 Elsevier Inc.
- African American
- Air pollution
- Cohort study