Extreme heat and high pollution levels are linked to a greater risk of heart attacks in a new study published in the health journal Circulation.
A news release said researchers in China studied 202,678 cardiac deaths that occurred between 2015-2020 in the Jiangsu province, an area in China that experiences all four seasons and has a range of pollution levels.
Researchers analyzed heat waves, cold spells and pollution levels of the areas where those who died resided, taking into account their age and gender, the report said.
CBS News said that “during two-day heat waves with heat indexes at or above the 90th percentile, ranging from 82.6 to 97.9 degrees Fahrenheit,” risk of a fatal heart attack increased 18%.
“The risk was 74% higher during four-day heat waves with heat indexes at or above the 97.5th percentile, ranging from 94.8 to 109.4 degrees,” per CBS News.
Catharina Giudice, an emergency medicine physician and a fellow at the Center for Climate, Health and the Global Environment at Harvard T.H. Chan School of Public Health, told The Washington Post, “As far as I am aware, this is one of the first studies that looks at death from heart attack as the end result of this type of exposure, and it does not surprise me.”
Study details
Researchers found that the greatest risk of a fatal heart attack was on days that had both extreme heat and high levels of air pollution.
According to the news release, women and older adults were more vulnerable to heart attacks than men or younger adults on days of extreme heat. Older adults also had an increased risk of heart attacks with extreme cold and high pollution levels.
The report said researchers estimated up to 2.8% of cardiac deaths were attributable to the extreme heat and pollution levels that exceeded air quality guidelines set by the World Health Organization.
“During four-day heat waves with fine particulate pollution levels above 37.5 micrograms per cubic meter, risk was twice as high. For context, the World Health Organization recommends no more than 15 micrograms per cubic meter for more than 3-4 days per year,” CBS News said.
Senior author Yuewei Liu, an associate professor of epidemiology in the School of Public Health at Sun Yat-sen University in Guangzhou, China, was quoted in the release: “Extreme temperature events are becoming more frequent, longer and more intense, and their adverse health effects have drawn growing concern.”
Giudice told the Post, “It’s getting hotter, lasting longer and happening more frequently. Heat makes cardiovascular disease worse. Pollution makes it worse. The two together are worse than each one independently.”
Liu said, “Our findings provide evidence that reducing exposure to both extreme temperatures and fine particulate pollution may be useful to prevent premature deaths from heart attack, especially for women and older adults,” per the release.