Long-term ambient PM 2.5 exposure associated with cardiovascular risk factors in Chinese less educated population

Introduction Long-term exposure to ambient air pollution is related to major cardiovascular risk factors including diabetes, hypertension, hyperlipidemia and overweight, but with few studies in high-concentration nations like China so far. We aimed to investigate the association between long-term exposure to ambient fine particulate matter (particles with an aerodynamic diameter ≤ 2.5 μm, PM 2.5 ) and major cardiovascular risk factors in China. Methods Adult participants with selected biochemical tests were recruited from the Chinese Physiological Constant and Health Condition (CPCHC) survey conducted from 2007 to 2011. Gridded PM 2.5 data used were derived from satellite-observed data with adjustment of ground-observed data. District-level PM 2.5 data were generated to estimate the association using multivariate logistic regression model and generalized additive model. Results A total of 19,236 participants from the CPCHC survey were included with an average age of 42.8 ± 16.1 years, of which nearly half were male (47.0%). The annual average PM 2.5 exposure before the CPCHC survey was 33.4 (14.8–53.4) μg/m 3 , ranging from 8.0 μg/m 3 (Xiwuqi) to 94.7 μg/m 3 (Chengdu). Elevated PM 2.5 was associated with increased prevalence of hypertension (odds ratio (OR) =1.022, 95% confidence interval (95%CI): 1.001, 1.043) and decreased prevalence of overweight (OR = 0.926, 95%CI: 0.910, 0.942). Education significantly interacted with PM 2.5 in association with all the interesting risk factors. Each 10 μg/m 3 increment of PM 2.5 was associated with increased prevalence of diabetes (OR = 1.118, 95%CI: 1.037, 1.206), hypertension (OR = 1.101, 95%CI: 1.056, 1.147), overweight (OR = 1.071, 95%CI: 1.030, 1.114) in participants with poor education, but not in well-educated population. PM 2.5 exposure was negatively associated with hyperlipidemia in all participants (OR = 0.939, 95%CI: 0.921, 0.957). The results were robust in all the sensitivity analyses. Conclusion Association between long-term PM 2.5 exposure and cardiovascular risk factors might be modified by education. PM 2.5 was associated with a higher prevalence of diabetes, hypertension, and overweight in a less-educated population with time-expose dependency. Long-term exposure to PM 2.5 might be associated with a lower prevalence of hyperlipidemia.