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 (nobs =7,108) of the population-based Heinz Nixdorf Recall study at baseline (2000–2003) and follow-up examination (2006–2008). Daily fine particulate matter (aerodynamic diameter≤2.5 μm, PM2.5 ; aerodynamic diameter≤10 μm, PM10 ), accumulation mode particle number (PNAM ), and nitrogen dioxide (NO2 ) 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 PM2.5 and PNAM exposures and blood glucose levels [e.g., 28-d PM2.5 : 0.91 mg/dL (95% CI: 0.38, 1.44) per 5.7 μg/m3 ]. PM2.5 , PM10 , and PNAM exposures were positively associated with HbA1c [e.g., 91-d PM2.5 : 0.07 p.p. (95% CI: 0.04, 0.10) per 4.0 μg/m3 ]. 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. NO2 exposure was not associated with blood glucose or with HbA1c.

CONCLUSIONS: Medium-term PM and PNAM 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.