A new study led by the University of Washington has uncovered a concerning link between long-term exposure to wildfire smoke and an increased risk of dementia. The research, published in JAMA Neurology, analyzed health records of 1.2 million Southern California residents aged 60 and older over an 11-year period.
The study found that for every 1 microgram per cubic meter increase in three-year average wildfire PM2.5 concentration, the odds of a dementia diagnosis rose by 18%. This risk was significantly higher compared to exposure from other sources of fine particulate matter (PM2.5).
Lead author Joan Casey, an associate professor at the University of Washington, emphasized the unique nature of wildfire smoke exposure. “Wildfire smoke is a different animal, in that it’s much spikier. There are many days where there’s no wildfire smoke, and there are some days where exposure is really, really extreme,” Casey explained.
The research also revealed troubling disparities in the impact of wildfire smoke exposure. Racialized individuals and those living in high-poverty areas faced an even greater risk of dementia diagnosis. The authors suggest that factors such as lower-quality housing and inability to afford air filtration systems may contribute to these disparities.
Climate change emerges as a key culprit in this growing health concern. As wildfires become more frequent and severe across the American West, the threat to cognitive health intensifies. The study period notably excluded the extreme wildfire seasons of 2020 and 2021, suggesting that the risk may be even greater in recent years.
While individuals can take steps to protect themselves with air filters and masks, Casey stresses the need for a global solution to climate change. As the population ages and wildfire seasons worsen, addressing this environmental health risk becomes increasingly urgent for public health and health equity.
“Research links wildfire smoke exposure with increased dementia risk” (November 25, 2024)
