Wildfire Smoke May Be Linked to Higher Risk of Dementia, New Study Finds

Smoke rises over the Forest Ranch area of Butte County as the Park fire rages near Chico, Calif., on July 26, 2024. Josh Edelson/AFP via Getty Images

Exposure to wildfire smoke may be linked to a higher risk of being diagnosed with dementia, according to a new study from the Alzheimer’s Association.

The study was conducted over 10 years and surveyed more than 1.2 million Southern California residents, according to a press release from the association.

“With the rising global incidence of wildfires, including in California and the western U.S., exposure to this type of air pollution is an increasing threat to brain health,” Alzheimer’s Association Senior Director of Scientific Programs and Research Claire Sexton, said in the statement.

California has been plagued over the years by wildfires, with the most recent inferno, the Park fire, scorching Northern California in Tehama and Butte counties north of Sacramento, consuming over 600 square miles on July 29.

Such wildfires expose Californians to a type of air pollution that includes fine particulate matter, or PM2.5, according to the association. Their findings indicated that the risk of dementia was higher with exposure to wildfire smoke more than any other type of pollution, such as that from motor vehicles or factories.

“These findings underscore the importance of enacting policies to prevent wildfires and investigating better methods to address them,” Ms. Sexton said.

According to the Alzheimer’s association, researchers working on the study noted a 21 percent increase in the odds of a dementia diagnosis over a three-year exposure to PM2.5.

They analyzed over 1 million health records from Kaiser Permanente’s southern California members who were at least 60 years old between 2009 and 2019, they said. Researchers additionally utilized satellite imagery and air quality monitoring data for the study.

Study author and neurology resident at the Hospital of the University of Pennsylvania, Dr. Holly Elser, said in the statement that air pollution produced by wildfires accounts for over 70 percent of PM2.5 exposure in California.

There are three reasons why the particulates produced by California wildfires are acutely dangerous, she said, including that they are produced at hotter temperatures, are smaller than other similar particles, and have a higher concentration of toxic chemicals.

To combat the health risks associated with wildfire pollution exposure, the Alzheimer’s association highlighted experts’ advice to update home air filtration systems and to stay inside if possible during smoky days. They also recommended wearing an N95 protective mask when outside.