Wildfire Smoke Poses Greater Dementia Risk Than Other Air Pollution, Study Finds

Recent research suggests that wildfire smoke may pose a greater risk to brain health compared to other forms of air pollution, potentially increasing the likelihood of dementia. This study was highlighted at the Alzheimer’s Association International Conference in Philadelphia, coinciding with recent air quality warnings due to widespread wildfires in the western United States.

The primary concern is fine particulate matter, or PM2.5, which are extremely small particles capable of penetrating deep into the lungs and entering the bloodstream. These particles originate from various sources including traffic, industrial emissions, and fires, and have been associated with heart and lung diseases. The new study adds to growing evidence that PM2.5 may also contribute to the risk of dementia.

Researchers analyzed health data from 1.2 million older adults in Southern California over a decade, from 2009 to 2019. They assessed the participants’ exposure to PM2.5 from wildfire smoke and other sources over three years using air quality monitoring and additional data.

The findings revealed a significant increase in dementia risk linked to wildfire smoke. Specifically, each 1 microgram per cubic meter increase in wildfire-related PM2.5 concentration was associated with a 21% higher risk of a new dementia diagnosis. In contrast, a similar increase in PM2.5 from non-wildfire sources correlated with only a 3% increase in dementia risk for every 3 micrograms per cubic meter.

The reason for the greater impact of wildfire smoke on dementia risk remains unclear. However, the increasing prevalence of wildfires calls for further investigation.

Maria Carrillo, the chief science officer at the Alzheimer’s Association, emphasized the importance of studying this issue further, particularly given that lower-income populations are more vulnerable to poor air quality and may have fewer opportunities to avoid exposure. Public health advice often recommends staying indoors when air quality deteriorates, but not everyone can follow this guidance due to work or living conditions.