Air Pollution and Glucose Metabolism: An Analysis in Non-Diabetic Participants of the Heinz Nixdorf Recall Study

BACKGROUND: Despite the importance of understanding the connection between air pollution exposure and diabetes, studies investigating links between air pollution and glucose metabolism in nondiabetic adults are limited. OBJECTIVE: We aimed to estimate the association of medium-term air pollution exposures with blood glucose and glycated hemoglobin A1c (HbA1c) among nondiabetics. METHODS: This study included observations from nondiabetic participants ([Formula: see text]) of the population-based Heinz Nixdorf Recall study at baseline (2000–2003) and follow-up examination (2006–2008). Daily fine particulate matter ([Formula: see text]; [Formula: see text]), accumulation mode particle number ([Formula: see text]), and nitrogen dioxide ([Formula: see text]) exposures were estimated at participants’ residences using the spatiotemporal European Air Pollution Dispersion (EURAD) chemistry transport model. We evaluated the associations between medium-term air pollution exposures (28- and 91-d means) and glucose metabolism measures using mixed linear regression and adjusting for season, meteorology, and personal characteristics. A range of other exposure windows (1-, 2-, 3-, 7-, 14-, 45-, 60-, 75-, 105-, 120-, and 182-d means) were also evaluated to identify potentially relevant biological windows. RESULTS: We observed positive associations between [Formula: see text] and [Formula: see text] exposures and blood glucose levels [e.g., 28-d [Formula: see text]: [Formula: see text] (95% CI: 0.38, 1.44) per [Formula: see text]]. [Formula: see text] , [Formula: see text] , and [Formula: see text] exposures were positively associated with HbA1c [e.g., 91-d [Formula: see text]: [Formula: see text] (95% CI: 0.04, 0.10) per [Formula: see text]]. Mean exposures during longer exposure windows (75- to 105-d) were most strongly associated with HbA1c, whereas 7- to 45-d exposures were most strongly associated with blood glucose. [Formula: see text] exposure was not associated with blood glucose or with HbA1c. CONCLUSIONS: Medium-term PM and [Formula: see text] exposures were positively associated with glucose measures in nondiabetic adults. These findings indicate that reducing ambient air pollution levels may decrease the risk of diabetes. https://doi.org/10.1289/EHP2561