Cold-related death rates more than doubled from 1999 to 2022 in the U.S. amid a surge in "extreme winter weather events" linked to climate change, a study has found.
Published Thursday in the Journal of the American Medical Association, the study reported that rates for all cold-related deaths rose from 0.44 for every 100,000 people in 1999 to 0.92 in 2022, driven by a "significant annual increase" from 2017-22 and a spike in fatalities citing cold weather only starting in 2016.
Out of 63.6 million deaths nationwide between 1999 and 2022, three Boston medical researchers found that 40,079, or 0.06%, of death certificates recorded "cold" as an underlying or contributing cause of death.
Dr. Rishi Wadhera, a co-author of the study and a physician at Harvard's Beth Israel Deaconess Medical Center, blamed "more extreme weather events related to climate change" for the trends.
"Another possible explanation for the recent rise in cold-related deaths is that a growing subset of the U.S. population may be more susceptible to cold weather events, due to the aging of the population and a rise in people experiencing homelessness," Dr. Wadhera said in an email.
The authors pointed to research showing that homelessness, social isolation, mental illness, preexisting health conditions and addiction place people at higher risk of freezing to death during winter storm surges.
Some doctors not connected to the study told The Washington Times that the figures suggest a looming public health crisis.
"It matters as many of these deaths are likely preventable and happening to more vulnerable populations at higher rates," said Dr. Panagis Galiatsatos, a physician at the Johns Hopkins School of Medicine.
While doctors said handwashing is important to prevent germs as more people stay indoors in the winter, they added it's mostly a myth that cold temperatures expose more people to viral infections.
"Simply getting cold does not increase your chance of getting exposed to a virus, which is spread through contact with infected droplets from another person by breathing them in or contact with a contaminated surface," said Dr. Craig Escude, a family physician and fellow of the American Academy of Developmental Medicine.
"However, there is ongoing research showing that a drop in temperature and humidity may reduce the body's ability to fight off a viral attack by reducing effective mucous production in the nose," he added. "So, in a sense, going outside in the cold could increase the risk of getting an infection."
According to the JAMA study, 4.23 out of every 100,000 people 75 years and older died from cold weather from 1999 to 2022, the largest of any age group. Deaths jumped among all demographics but were highest for men, American Indians or Alaska Natives and Black people.
At the same time, people ages 45 to 74 experienced the sharpest annual increases, with surges in deaths among Hispanic and White people leading the way.
The Midwest led the way in cold-related deaths, reporting the highest rate (1.41 deaths per 100,000 people) and annual increase (4.3%) of any part of the country.
Michael Liu, a Harvard Medical School student who conducted the study's statistical analysis, said the findings add to evidence that climate change causes both "warmer average temperatures" in the summer and winter freezes.
"Understanding these patterns is critical for public health efforts that aim to mitigate weather-related deaths, especially for the most vulnerable populations," Mr. Liu said.