Particulate matter exposure ups risk of cardiovascular disease

Long-term exposure to particulate matter (PM_2.5) increases the risk of cardiovascular diseases (CVD), with more evident effects at higher PM_2.5 levels, according to a recent China study.

To examine the association between CVD risks and long-term PM_2.5 exposure, a nationwide cohort study, China-PAR (Prediction for Atherosclerotic Cardiovascular Disease Risk in China), was used, comprising a total of 116,972 adults without CVD in 2000. Participants were followed through 2015.

For assessment of exposure, the authors used satellite-based PM_2.5 concentrations at 1-km spatial resolution during the study period. They then generated a Cox proportional hazards model with time-varying exposures to estimate the CVD risks associated with PM_2.5 exposure, adjusting for individual risk factors.

At the China-PAR sites, mean concentrations of PM_2.5 ranged from 25.5–114.0 μg/m³ per year. For each 10-μg/m³ increase in PM_2.5 exposures, risk increased by 25 percent for CVD incidence (hazard ratio [HR], 1.251, 95 percent confidence interval [CI], 1.220–1.283) and by 16 percent for CVD mortality (HR, 1.164, 95 percent CI, 1.117–1.213). Higher levels of PM_2.5 led to steeper slopes of concentration-response functions of PM_2.5 exposure and CVD risks.

Moreover, participants who were older, living in rural areas and never smokers were more vulnerable to the adverse effects of PM_2.5 exposure.

“These findings expand the current knowledge on adverse health effects of severe air pollution and highlight the potential cardiovascular benefits of air quality improvement in China and other low- and middle-income countries,” the authors said.