Long-term exposure to air pollution significantly increases the risk of cardiovascular disease (CVD), with the greatest danger facing individuals who already have cardiovascular-kidney-metabolic (CKM) syndrome, according to a new study published in The Innovation Medicine.

Researchers from Fudan University analyzed data from 3,103 participants in the China Health and Retirement Longitudinal Study (CHARLS) over a four-year period. They found that for every 10 μg/m³ increase in fine particulate matter (PM2.5) and coarse particulate matter (PM2.5–10), the odds of developing CVD rose by approximately 10%.

The study is the first to show that CKM syndrome—a condition encompassing the interconnected risks of heart disease, kidney disease, diabetes, and obesity—significantly modifies this risk.

"We observed a clear gradient: individuals at more advanced CKM stages were far more susceptible to the harmful cardiovascular effects of air pollution," said Dr. Cong Liu, corresponding author of the study. "This suggests that CKM staging could be a powerful tool for identifying vulnerable populations and guiding precision prevention strategies."

The research also uncovered a surprising link to cooking fuel. "A stronger association between PM exposure and heart disease was found among those using 'clean' fuels like gas or electricity," shared Liu. "This may be because these households have better healthcare access, leading to higher diagnosis rates, or because the relative contribution of indoor pollution is lower, making ambient pollution's effect more apparent."

Furthermore, the researchers found that accelerated biological aging mediated nearly 9% of the PM2.5-related CVD risk. "Air pollution appears to accelerate the body's aging process at a molecular level, which in turn increases the risk for heart disease," explained first author Yuan Liu. "This provides a biological pathway linking the environment to chronic disease."

The findings underscore the need for stricter air quality standards and targeted health interventions for people with CKM syndrome, a condition that affects nearly 90% of adults in the U.S. according to recent estimates.