Long-term exposure to PM2.5 and its components is associated with elevated blood pressure and hypertension prevalence: Evidence from rural adults

Abstract

The toxicity of fine particulate matter (PM2.5) is determined by its components, while the associations of PM2.5 components with blood pressure (BP) is limited, especially in economically in rural areas. This study aimed to explore the associations of PM2.5 and its chemical components with systolic BP (SBP), diastolic BP (DBP), pulse pressure (PP), mean artery pressure (MAP) levels and hypertension prevalence, and to identify the detrimental components in Chinese rural areas. 39,211 adults from the Henan Rural Cohort were included during 2015-2017. Different periods of PM2.5 and chemical components were estimated by hybrid satellite model. The single-pollutant, component-PM2.5 model, component-residual model and component-proportion model were applied to explore the associations of pollutants with BP levels and hypertension prevalence. Exposure-response (E-R) relationships, stratified analyses and sensitivity analyses were used to explore these associations further. 12,826 (32.71%) were identified with hypertension. For each1 μ g/m3 increase of pollutants, the adjusted odds ratio (OR) for hypertension prevalence was 1.03 for PM2.5 total, 1.40 for BC, 1.16 for NH4+, 1.08 for NO3-,1.17 for OM, 1.12 for SO42- and 1.25 for SOIL in the single-pollutant model. BC and SOIL were significant in the component-PM2.5 model, component-residual model and component-proportion model. Similarly, the associations of these pollutants with elevated SBP, DBP, PP and MAP were also found in aforementioned four models. These pollutants were most strongly associated with SBP. Most of the associations were non-linear in E-R relationships. The groups of older, the men, had lower per capita monthly income, lower educational level and higher BMI were more vulnerable to these pollutants in stratified analyses. The results remained stable in sensitivity analyses. Long-term exposure to PM2.5 and its components, especially BC and SOIL, was associated with elevated BP and hypertension prevalence in rural adults, and decreasing pollutants may provide additional benefits.