A new study using cardiac MRI shows that long-term exposure to air pollution is linked to early signs of heart muscle damage, underscoring the urgent need for improved air quality standards.
Long-term exposure to air pollution has been found to cause early signs of heart damage, according to a recent study published in Radiology, a journal of the Radiological Society of North America (RSNA).
Utilizing cardiac MRI, the researchers discovered that fine particulate matter in the air, known as PM2.5, is associated with diffuse myocardial fibrosis — scarring in the heart muscle that can precede heart failure.
“We know that if you’re exposed to air pollution, you’re at higher risk of cardiac disease, including higher risk of having a heart attack,” senior author Kate Hanneman, an associate professor and vice chair of research at the University of Toronto and a clinician scientist at the Toronto General Hospital Research Institute, said in a news release. “We wanted to understand what drives this increased risk at the tissue level.”
The study included 694 participants, consisting of both healthy individuals and those with dilated cardiomyopathy, a condition that makes it harder for the heart to pump blood.
Using cardiac MRI, a non-invasive imaging technique, the researchers were able to quantify myocardial fibrosis and evaluate its relationship with long-term exposure to PM2.5 pollutants.
These particles, measuring 2.5 micrometers or less, are small enough to enter the bloodstream through the lungs, originating from sources like vehicle exhaust, industrial emissions and wildfire smoke.
Higher levels of myocardial fibrosis were found in both healthy individuals and those with cardiomyopathy who were exposed to higher long-term levels of fine particulate air pollution. This suggests that myocardial fibrosis might be a mechanism through which air pollution contributes to cardiovascular complications.
The study also found that the largest effects were seen in women, smokers and patients with hypertension.
“Even modest increases in air pollution levels appear to have measurable effects on the heart,” added Hanneman. “Our study suggests that air quality may play a significant role in changes to heart structure, potentially setting the stage for future cardiovascular disease.”
This research adds to the growing evidence that air pollution is a cardiovascular risk factor, contributing to residual risk not fully accounted for by traditional clinical predictors such as smoking or hypertension.
It also emphasizes the need for public health measures to further reduce air pollution exposure, as even exposure levels below many global air quality guidelines can pose significant health risks.
“There have been improvements in air quality over the past decade, both in Canada and the United States,” Hanneman added. “But we still have a long way to go.”
The findings of this study underscore the importance of accounting for a patient’s long-term exposure to air pollution in heart disease risk assessments, potentially addressing health inequities stemming from environmental factors.
“Medical imaging can be used as a tool to understand environmental effects on a patient’s health,” Hanneman added. “As radiologists, we have a tremendous opportunity to use imaging to identify and quantify some of the health effects of environmental exposures in various organ systems.”