Studies link higher levels of air pollution to the risk of acute myocardial infarction or heart attack. How these risks vary by demographics, type of air pollution, and type of heart attack, however, early studies have produced various results. These links are crucial to reveal, as air pollution may rise along with other health stressors, such as heat, as climate change worsens.
Zhang et al. Data on heart attacks from 2322 patients aged 18-55 in the United States draw from differences in recovery: the role of gender in the outcomes of young AMI patients (Virgo) studies. Nearly 70% of patients are female, underpopulated in previous studies. Researchers studied the occurrence of heart attacks and concurrent levels of ozone and PM2.5 (2.5 microns in diameter or smaller air particles) near the patient's house.
It is worth noting that the researchers analyzed different types of heart attacks separately. Type 1 heart attacks are caused by plaque accumulation and blood clot formation, while Type 2 heart attacks are caused by diseases such as hypotension that reduce oxygen supply without the formation of clots. STEMI (ST segment elevation myocardial infarction) occurs when a completely blocked artery stops the blood and causes a specific electrocardiogram (ECG) pattern. When the arteries are partially blocked, non-stem occurs, reducing blood flow without the same clear ECG changes in STEMI.
The authors found that higher ozone levels were positively correlated with heart attacks 4-5 days later, although they found no association with PM2.5 level. They said ozone levels were more closely related to type 2 heart attacks and non-STAMI heart attacks, and they found no association between ozone levels and STEMI heart attacks. Furthermore, non-Hispanic black patients had higher correlations between ozone levels and heart attacks compared with non-Hispanic whites. The association between ozone and heart attacks remains significant, even if the levels of ozone are lower than those recommended by the World Health Organization.
The authors say their findings are in stark contrast to those found in some previous studies. For example, their results indicate a link between air pollution and non-STAMI heart attacks, and they cannot find the link between PM2.5 and heart attack. The authors' analysis also showed a small, though statistically unimportant, enhanced the ozone-heart attack correlation compared to the colder months, which they said could predict increased heart attacks under climate change. ((Geographical Healthhttps://doi.org/10.1029/2024GH001234, 2025)
Originally published by EOS, the story is part of Climate Now, a global news collaboration that enhances reporting on climate stories.
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