Associations between ambient fine particulate air pollution and hypertension: A nationwide cross-sectional study in China.

Limited evidence is available regarding the long-term effects of fine particulate (PM2.5) air pollution on hypertension in developing countries. This study aimed to explore the associations of long-term exposure to PM2.5 with hypertension prevalence and blood pressure (BP) in China. We conducted a cross-sectional study based on a nationally representative survey (13,975 participants). We estimated the long-term average exposure to PM2.5 for all subjects during the study period (June 2011 to March 2012) by a satellite-based model with a spatial resolution of 10×10km. We applied multivariable logistic regression models to evaluate the associations between PM2.5 and hypertension prevalence and linear regression models for the associations between PM2.5 and systolic BP and diastolic BP. We also explored potential effect modification by stratification analyses. There were 5715 cases of hypertension, accounting for 40.9% of the study population in this analysis. The annual mean exposure to PM2.5 for all participants was 72.8μg/m3 on average. An interquartile range increase (IQR, 41.7μg/m3) in PM2.5 was associated with higher prevalence of hypertension with an odds ratio of 1.11 [95% confidence interval (CI): 1.05, 1.17]. Systolic BP increased by 0.60mmHg (95% CI: 0.05, 1.15) per an IQR increase in PM2.5. The effects of PM2.5 on hypertension prevalence were stronger among middle-aged, obese and urban participants. This national study indicated that long-term exposure to PM2.5 was associated with increased prevalence of hypertension and slightly higher systolic BP in China.