Air pollution is known to harm heart health, but researchers are now uncovering how it may directly damage the heart’s structure. A new study has found that long-term exposure to PM2.5 is linked to increased heart tissue scarring, known as myocardial fibrosis, even in people without diagnosed heart disease.
The study involved 694 adults who underwent heart scans between 2018 and 2022. Of these, 493 had dilated cardiomyopathy (a condition where the heart becomes weakened and enlarged) while 201 had normal heart scans.
Senior author Kate Hanneman, from the Department of Medical Imaging at the Temerty Faculty of Medicine, University of Toronto and University Health Network in Toronto, said: ‘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. We wanted to understand what drives this increased risk at the tissue level.’
The researchers used advanced MRI technology to detect subtle signs of fibrosis, an abnormal buildup of stiff tissue in the heart that can lead to serious complications like heart failure.
Long-term PM2.5 exposure was calculated for each patient from the closest monitoring station to their residential address in the year period immediately prior to their cardiac MRI examination.
It was found that for every small increase in average PM2.5 exposure over one year, there was a significant increase in the amount of myocardial fibrosis, as measured by the MRI scans.
This was true not only for patients with existing heart disease but also for those with no signs of cardiac problems.
Some groups appeared to be especially vulnerable. Women, smokers, and people with high blood pressure showed stronger associations between air pollution exposure and heart fibrosis, suggesting that certain groups may be at greater risk of developing pollution-related heart damage, even before any symptoms appear.
It should be noted that these effects were seen at pollution levels below Canada’s air quality standards.
Dr. Hanneman said. ‘Even modest increases in air pollution levels appear to have measurable effects on the heart. Our study suggests that air quality may play a significant role in changes to heart structure, potentially setting the stage for future cardiovascular disease.
‘Public health measures are needed to further reduce long-term air pollution exposure. There have been improvements in air quality over the past decade, both in Canada and the United States, but we still have a long way to go.’
The full report can be read here.
Photo: TheDigitalArtist
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