Air pollution has been linked to more severe heart disease, and there’s a notable difference between men and women, according to a new study
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Air pollution is a constantly growing environmental issue. In 2021, it contributed to an estimated 2.46 million cardiovascular deaths. It is a huge environmental risk to health and plays a major role in causing heart attacks and strokes.
Two common pollutants found in urban air include ambient fine particulate matter (PM2.5) and nitrogen dioxide (NO2). PM2.5 are about 30 times smaller than a human hair, allowing them to penetrate deep into the lungs and bloodstream. It originates from sources such as vehicle exhausts, industrial emissions and wildfire smoke. NO2 is a harmful gas that comes from burning fossil fuels in vehicles, power plants and industrial processes.
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A study of more than 11,000 adults, presented at the annual meeting of the Radiological Society of North America (RSNA) has highlighted the importance of improving air quality, to reduce the risk of cardiovascular disease. Its findings show that levels of air pollution below or near regulatory standards and typical urban exposures are associated with early signs of heart disease, sometimes before symptoms can appear.
The study examined data from adults who had undergone cardiac CT scans between 2012 and 2023, across three major Toronto hospitals. Researchers matched patients’ postal codes, with air quality data, allowing them to estimate each person’s average exposure to air pollution over the 10 years before the CT. Three signs of coronary artery disease were assessed: calcium score (plaque buildup in the arteries), total plaque burden (total amount of fatty buildup in the arteries) and obstructive stenosis (artery narrowing).
Researchers found that for every increase in long-term PM2.5 of one microgram per cubic meter, calcium buildup in the coronary arteries increased by 11 per cent, the chance of having more plaque increased by 13 per cent, as well as the chance of obstructive disease increasing by 23 per cent. Exposure to NO2 followed a similar pattern, however with smaller effect sizes for every one part per billion increase.
Long-term exposure to common air pollutants have been linked with more advanced coronary artery disease – however, there’s a difference between men and women.
Lead author of the study and cardiothoracic imaging fellow in the Department of Medical Imaging, Temerty Faculty of Medicine, University of Toronto, and University Health Network (UHN), Felipe Castillo Aravena, said: ‘Overall, higher long-term exposure to air pollution was associated with more coronary artery disease on cardiac CT in both women and men.’
Dr. Castillo adds: ‘In women, long-term exposure to fine particulate matter was linked to higher calcium scores and more severe narrowing of the arteries. In men, higher long-term exposure to fine particulate matter was associated with higher calcium scores and higher plaque burden.’
How does air pollution compare in cities around the world?
99 per cent of the world’s population breathes bad air every day, and air pollution kills an estimated seven million people worldwide every year, according to the World Health Organization.
The top five cities with the worst air quality are: Cairo (Egypt), Lahore (Pakistan), Delhi (India), Hanoi (Vietnam) and Dhaka (Bangladesh), which fall under unhealthy and very unhealthy air quality index.
On the flip side, the top five cities with the best air quality are: Oslo (Norway), Kobe and Kyoto (Japan), Birmingham (United Kingdom) and Lisbon (Portugal), which all have good air quality index.
