Long-Term Effects of Ambient PM_2.5 on Hypertension and Blood Pressure and Attributable Risk among Older Chinese Adults

Long-term exposure to ambient fine particulate pollution (PM_2.5) has been associated with cardiovascular diseases. Hypertension, a major risk factor for cardiovascular diseases, has also been hypothesized to be linked to PM_2.5. However, epidemiological evidence has been mixed. We examined long-term association between ambient PM_2.5 and hypertension and blood pressure. We interviewed 12 665 participants aged 50 years and older and measured their blood pressures. Annual average PM_2.5 concentrations were estimated for each community using satellite data. We applied 2-level logistic regression models to examine the associations and estimated hypertension burden attributable to ambient PM_2.5. For each 10 μg/m³ increase in ambient PM_2.5, the adjusted odds ratio of hypertension was 1.14 (95% confidence interval, 1.07-1.22). Stratified analyses found that overweight and obesity could enhance the association, and consumption of fruit was associated with lower risk. We further estimated that 11.75% (95% confidence interval, 5.82%-18.53%) of the hypertension cases (corresponding to 914, 95% confidence interval, 453-1442 cases) could be attributable to ambient PM_2.5 in the study population. Findings suggest that long-term exposure to ambient PM_2.5 might be an important risk factor of hypertension and is responsible for significant hypertension burden in adults in China. A higher consumption of fruit may mitigate, whereas overweight and obesity could enhance this effect.