Long-term air pollution exposure and metabolic syndrome prevalence: A longitudinal cohort study from the electricity generating authority of Thailand study

Abstract

BACKGROUND AND AIM: It has been reported that long-term exposure to air pollution is linked to metabolic syndrome (MetS), which is an important risk factor for cardiovascular diseases. However, no study has investigated the epidemiological association between long-term air pollution exposure and MetS in Southeast Asia. We examined the association between long-term exposure to air pollution and prevalence of MetS in workers of Electricity Generating Authority of Thailand (EGAT) in Bangkok metropolitan region, Thailand. METHODS: The diagnosis of MetS was made based on the criteria defined by the National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) that modified waist circumference cut-points for Asians. This study was based on 1,839 subjects of EGAT1 cohort study (2002-2012; mean age 58.3 years at the baseline). Blood tests were measured in 2002, 2007, and 2012. One-year average air pollution concentrations of particulate matter ≤10 μm in diameter (PM10), sulfur dioxide (SO2), nitrogen dioxide (NO2), ozone (O3), and carbon monoxide (CO) prior to the laboratory test was estimated using ordinary kriging method. We applied the logistic mixed effects models to calculate odds ratios (ORs) of the MetS prevalence per an interquartile range increase in air pollution. RESULTS:After controlling for potential confounders, higher prevalence of MetS was significantly associated with increased PM10 (ORs = 1.31, 95%CI: 1.1, 1.56) and CO (ORs = 1.2, 95%CI: 1.04, 1.38). Although not statistically significant, we also found the positive association between SO2 and prevalent MetS (ORs = 1.26, 95%CI: 0.97, 1.64). In contrast, O3 was inversely associated with prevalence of MetS (ORs = 0.59, 95%CI: 0.46, 0.76). CONCLUSIONS:Long-term exposure to air pollutants, especially for PM10 and CO were positively associated with prevalence of MetS in subjects of EGAT cohort study. KEYWORDS: Air pollution, long-term exposure, particulate matter, ozone, cardiovascular diseases