Wildfire particulate exposure linked to higher odds of dementia diagnosis
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Key takeaways:
- Odds of dementia rose 21% for every increase of 1 µg per cubic meter in 3-year average wildfire fine particulate exposure.
- For non-wildfire particulates, odds were higher for every 1 µg per cubic meter.
PHILADELPHIA — Exposure to wildfire smoke and fine particulates was associated with increased risk for a dementia diagnosis in a cohort of older adults, data show.
“Air pollution produced by wildfires now accounts for more than 70% of total [fine particulate matter] exposure on poor air quality days in California,” Holly C. Elser, MD, MPH, PhD, an epidemiologist and resident physician in the department of neurology at the Hospital of the University of Pennsylvania, said in a related release regarding the study, which was presented at the Alzheimer’s Association International Conference. “This is a real problem.”
Elser and colleagues sought to examine associations between long-term exposure to wildfire particulate matter and dementia in a cohort of older adult patients from Kaiser Permanente Southern California between 2009 and 2019.
Their retrospective open cohort study included 1,227,241 individuals (49% white; 53% female; 54% married) who did not have a dementia diagnosis at baseline.
Total fine particulate matter concentrations were estimated from sources such as satellite-derived aerosol properties and Environmental Protection Agency monitoring. The researchers subsequently separated wildfire and non-wildfire fine particulate matter by utilizing air quality monitoring data, satellite imagery and machine learning techniques, then determined exposures to both sources of fine particulates and estimated 3-year average concentrations according to census tract data, which were updated on a quarterly basis. These data were then compared with diagnoses of dementia in participants’ health records.
All analysis models included fixed effects for the calendar years of the study, then adjusted based on a broad range of socioeconomic factors including age, sex, ethnicity, smoking status and population density.
Elser and colleagues reported a 21% increase in the odds of dementia diagnosis for every increase of 1 µg per cubic meter in the 3-year average wildfire fine particulate exposure.
They also calculated a 3% increased risk for dementia diagnosis for every increase of 3 µg per cubic meter over within the 3-year average of non-wildfire fine particulate exposure.
Over the study period, the mean wildfire fine particulate matter concentration was 0.09 (IQR: 9.6–12.4). For non-wildfire particulates, the odds of dementia diagnosis were 1 higher for every 1 µg per cubic meter for a higher 3-year average exposure (OR = 1.01; 95% CI, 1-1.01).
“In light of our large, long-term study, it’s apparent the risk from exposure due to wildfire smoke is an even bigger concern,” Elser said in the release.
Editor's Note: This story was updated on July 30, 2024, to reflect a change in data from a revised release featuring the study.