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

Abstract

Introduction: The toxicity of fine particulate matter (PM_2.5) is determined by its components, while the evidence regarding associations of PM_2.5 components with blood pressure (BP) is limited, especially in rural areas.

Objectives: This study aimed to explore the associations of PM_2.5 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 key components in Chinese rural areas.

Methods: 39,211 adults from the Henan Rural Cohort were included during 2015-2017. Different periods of PM_2.5 and chemical components were estimated by hybrid satellite model. The single-pollutant, component-PM_2.5 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.

Results: 12,826 (32.71%) were identified with hypertension. For each 1 μg/m³ increase of pollutants, the adjusted odds ratio (OR) for hypertension prevalence was 1.03 for PM_2.5 mass, 1.40 for BC, 1.16 for NH₄⁺, 1.08 for NO₃^-, 1.17 for OM, 1.12 for SO₄^2- and 1.25 for SOIL in the single-pollutant model. BC and SOIL were statistically significant in the component-PM_2.5 model, component-residual model and component-proportion model. Similarly, associations of these pollutants with elevated BP levels were also found in aforementioned four models. These pollutants produced a stronger association with SBP than DBP, PP and MAP. Most of associations were non-linear in E-R relationships. The groups of older, the men, with 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.

Conclusion: Long-term exposure to PM_2.5 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.

Keywords: Blood pressure (BP); Hypertension prevalence; Long-term exposure; PM(2.5) and chemical components; Rural adults.