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

Limited evidence is available regarding the long-term effects of fine particulate (PM_2.5) air pollution on hypertension in developing countries. This study aimed to explore the associations of long-term exposure to PM_2.5 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 PM_2.5 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 PM_2.5 and hypertension prevalence and linear regression models for the associations between PM_2.5 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 PM_2.5 for all participants was 72.8μg/m³ on average. An interquartile range increase (IQR, 41.7μg/m³) in PM_2.5 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 PM_2.5. The effects of PM_2.5 on hypertension prevalence were stronger among middle-aged, obese and urban participants. This national study indicated that long-term exposure to PM_2.5 was associated with increased prevalence of hypertension and slightly higher systolic BP in China.