Ambient PM₁ air pollution and cardiovascular disease prevalence: Insights from the 33 Communities Chinese Health...

Evidence on the association between long-term exposure to particulate matter with aerodynamic diameter ≤2.5 μm (PM_2.5) and cardiovascular disease (CVD) is scarce in developing countries. Moreover, few studies assessed the role of the PM₁ (≤1.0 μm) size fraction and CVD. We investigated the associations between PM₁ and PM_2.5 and CVD prevalence in Chinese adults.

In 2009, we randomly recruited 24,845 adults at the age of 18-74 years from 33 communities in Northeastern China. CVD status was determined by self-report of doctor-diagnosed CVD. Three-year (2006-08) average concentrations of PM₁ and PM_2.5 were assigned using a satellite-based exposure. We used spatial Generalized Linear Mixed Models to evaluate the associations between air pollutants and CVD prevalence, adjusting for multiple covariates. Stratified and interaction analyses and sensitivity analyses were also performed.

A 10 μg/m³ increase in long-term exposure to ambient PM₁ levels was associated a 12% higher odds for having CVD (OR = 1.12; 95% CI = 1.05-1.20). Compared to PM₁, association between PM_2.5 and CVD was lower (OR = 1.06; 95% CI = 1.01-1.11). No significant association was observed for PM_1-2.5 (1-2.5 μm) size fraction (OR = 0.98; 95% CI = 0.85-1.13). Stratified analyses showed greater effect estimates in men and the elder.

Long-term PM₁ exposure was positively related to CVD, especially in men and the elder. In addition, PM₁ may play a greater role than PM_2.5 in associations with CVD. Further longitudinal studies are warranted to confirm our findings.