Extreme heat linked to dramatic rise in certain injuries, study finds

In light of the smouldering waves of record temperatures that many people across the world had to face this summer, a large-scale study based on US hospital data has identified a wide range of medical problems that become more common as temperatures rise.

Researchers from Northwestern University Feinberg School of Medicine in the US city of Chicago examined 916,404 visits to hospital emergency departments and urgent care centres between 2011 and 2023. They looked for patterns in illnesses and injuries recorded when temperatures reached 33.7 degrees Celsius or higher, as American media outlets report.

The findings, published this week in Science Advances, showed that more than a dozen broad categories of injuries and illnesses became more frequent on extremely hot days, including some conditions not typically associated with heat exposure.

“The sound of the city is the sound of ambulances,” said study senior author Dr. Abel Kho, a professor of internal medicine at Northwestern. “Hot days are just like, something’s going to happen.”

According to Kho, people are significantly more likely to suffer external injuries during periods of extreme heat, while certain existing medical conditions can also worsen. He particularly pointed to kidney-related problems and complications involving the effects of drugs, including cannabinoids.

The researchers' analysis of the extensive hospital records found increases in accidental gunshot wounds, kidney problems, skin conditions, varicose veins and mental health problems associated with marijuana use during periods of extreme heat.

Some of the health problems increased two- or threefold compared with days when temperatures remained below the 33.7C threshold. Accidental gunshot wounds showed an especially dramatic increase, rising by more than 30 times, according to the study. Unspecified injuries resulting from assaults showed an even greater increase.

The researchers say the findings demonstrate that the health consequences of extreme heat extend well beyond familiar heat-related illnesses such as heat exhaustion and heatstroke.

The study “helps confirm that we’ve been underestimating health risks from heat exposures,” Dr. Jonathan Patz, chair of health and environment at the University of Wisconsin, commented on the study that he was not involved with in remarks to the AP.

The findings also highlight the broader consequences of increasingly frequent extreme-heat events, which are becoming more common as the planet warms.

“It also is a reminder that the price of climate change is increased illness, strain on our health care system and health care costs,” Dr. Courtney Howard, a Canadian emergency room physician, chair of the Global Climate and Health Alliance and president-elect of the Canadian Medical Association, also told the outlet.

While the study centres on records gathered in a Chicago hospital, the article refers to expert opinions that argue the findings highlight underestimated health problems and rising costs that affect much of the world's population that experiences a changing climate.

By Nazrin Sadigova