Is Particle Pollution in Outdoor Air Associated with Metabolic Control in Type 2 Diabetes?

Background: There is growing evidence that air pollutants are associated with the risk of type 2 diabetes. Subclinical inflammation may be a mechanism linking air pollution with diabetes. Information is lacking whether air pollution also contributes to worse metabolic control in newly diagnosed type 2 diabetes. We examined the hypothesis that residential particulate matter (PM10) is associated with HbA(1c) concentration in newly diagnosed type 2 diabetes. Methods: Nationwide regional levels of particulate matter with a diameter of <= 10 mu m (PM10) were obtained in 2009 from background monitoring stations in Germany (Federal Environmental Agency) and assigned to place of residency of 9,102 newly diagnosed diabetes patients registered in the DPV database throughout Germany (age 65.5 +/- 13.5 yrs; males: 52.1%). Mean HbA(1c) (%) levels stratified for air pollution quartiles (PM10 in mu g/m(3)) were estimated using linear regression models adjusting for age, sex, BMI, diabetes duration, geographic region, year of ascertainment, and social indicators. Findings: In both men and women, adjusted HbA(1c) was significantly lower in the lowest quartile of PM10 exposure in comparison to quartiles Q2-Q4. Largest differences in adjusted HbA(1c) (95% CI) were seen comparing lowest quartiles of exposure with highest quartiles (men %: -0.42 (-0.62; -0.23)/mmol/mol: -28.11 (-30.30; -26.04), women, %: -0.28 (-0.47; -0.09)/mmol/mol: -0.28 (-0.47; -0.09)). Interpretation: Air pollution may be associated with higher HbA(1c) levels in newly diagnosed type 2 diabetes patients. Further studies are warranted to examine this association.