Benefit of Glycemic Control for Reducing the Effects of Air Pollution on Blood Pressure: A Panel Study

Objective: Diabetes mellitus (DM) is known to aggravate the association between air pollution and cardiovascular diseases, such as hypertension. However, the influence may differ based on the degree of glycemic control. Therefore, we hypothesized that the adverse effects of air pollutants on Blood Pressure (BP) in patients with controlled DM would be less than those in patients with uncontrolled DM. Methods: Data were analyzed from a panel study of 560 elderly participants, conducted between 2008 and 2010 in Seoul, Korea. Mixed effects models were used to assess the association of air pollutants [particulate matter with aerodynamic diameters< 10 mu m (PM10), PM2.5, PM10-2.5, nitrogen dioxide, ozone, sulfur dioxide, and carbon monoxide] with BP. We compared the magnitude of the effects among individuals with controlled and uncontrolled DM and those without DM. Results: Increases in the interquartile range levels of PM10 were significantly associated with 2.0 mmHg (95% CI, 0.7-41.7 mmHg) increases in systolic BP (SBP) and 2.0 mmHg (95% CI, 1.2-41.7 mmHg) increases in diastolic BP (DBP) when we analyzed all participants. Most of the other air pollutants, except ozone, were also associated with significant increases in BP. When we compared the BP changes among the three groups (non-DM, controlled DM, and uncontrolled DM), significant increases in SBP and DBP were observed in participants with uncontrolled DM and those without DM; significant BP increases were not observed in participants with controlled DM. Conclusion: Glycemic control provided benefits for alleviating BP changes associated with exposure to air pollutants.