Ambient Fine Particulate Matter, Outdoor Temperature, and Risk of Metabolic Syndrome

摘要

Ambient air pollution and temperature have been linked with cardiovascular morbidity and mortality. Metabolic syndrome and its components-abdominal obesity, elevated fasting blood glucose concentration, low highdensity lipoprotein cholesterol concentration, hypertension, and hypertriglyceridemia-predict cardiovascular disease, but the environmental causes are understudied. In this study, we prospectively examined the long-term associations of air pollution, defined as particulate matter with an aerodynamic diameter less than or equal to 2.5 mu m (PM2.5), and temperature with the development of metabolic syndrome and its components. Using covariate-adjustment Cox proportional hazards models, we estimated associations of mean annual PM2.5 concentration and temperature with risk of incident metabolic dysfunctions between 1993 and 2011 in 587 elderly (mean = 70 (standard deviation, 7) years of age) male participants in the Normative Aging Study. A 1-mu g/m3 increase in mean annual PM2.5 concentration was associated with a higher risk of developing metabolic syndrome (hazard ratio (HR) = 1.27, 95 confidence interval (CI): 1.06, 1.52), an elevated fasting blood glucose level (HR = 1.20, 95 CI: 1.03, 1.39), and hypertriglyceridemia (HR = 1.14, 95 CI: 1.00, 1.30). Our findings for metabolic syndrome and high fasting blood glucose remained significant for PM2.5 levels below the Environmental Protection Agency's health-safety limit (12 mu g/m3). A 1 degrees C increase in mean annual temperature was associated with a higher risk of developing elevated fasting blood glucose (HR = 1.33, 95 CI: 1.14, 1.56). Men living in neighborhoods with worse air quality-with higher PM2.5 levels and/or temperatures than average-showed increased risk of developing metabolic dysfunctions.