Indirect effect of remote NO2 and PM2.5 exposure on declines in episodic memory mediated by depressive symptoms
WEDNESDAY, Nov. 18, 2020 (HealthDay News) — For the oldest-old women, exposure to air pollutants in late life is associated with depressive symptoms (DS) and is indirectly associated with accelerated decline in episodic memory (EM), according to a study published online Nov. 18 in the Journal of the American Geriatrics Society.
Andrew J. Petkus, Ph.D., from the University of Southern California in Los Angeles, and colleagues conducted a prospective cohort study in a geographically diverse community-dwelling population of 1,583 dementia-free women aged 80 years and older. Participants completed up to six annual memory assessments and the 15-item Geriatric Depression Scale (GDS-15). Three-year average exposures to regional particulate matter with aerodynamic diameter <2.5 µm (PM2.5) and gaseous nitrogen dioxide (NO2) were estimated at baseline and during a remote period 10 years earlier.
The researchers observed a significant association between remote NO2 and PM2.5 exposure and larger increases in standardized DS, although the magnitude of the difference was less than 1 point on the GDS-15. Higher DS were associated with accelerated decline in EM; DS mediated the significant indirect effect of remote NO2 and PM2.5 exposure on EM declines. No other significant indirect exposure effects were seen.
“We know late-life exposures to ambient air pollutants accelerate brain aging and increase the dementia risk, but our new findings suggest the oldest-old populations may respond to air pollution neurotoxicity in a different way that needs to be investigated further,” a coauthor said in a statement.
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