Short-Term PM2.5 Exposure Impacts Cognitive Performance: A Longitudinal Repeated Measures Study of the Western US 2017-2018
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Background and Aim. There is increasing evidence that air pollution exposure adversely impacts cognitive health. While wildfire smoke is a pollutant of growing concern, there is little evidence to date if short-term exposure impacts cognitive function. Using repeated measures, we aimed to identify and quantify the relationship between daily and sub-daily PM2.5 and smoke exposure and changes in cognitive performance in adults.
Methods. Cognitive performance data was obtained for 1,467 Lumosity users, age 18+, who completed 20 plays of a brain-training game targeted to improve cognitive flexibility in the western United States during 2017-2018. We considered two measures of daily and sub-daily air pollution exposure: (1) PM2.5 concentration estimates, obtained from a Bayesian Maximum Entropy data fusion of observations from FRM/FEM and PurpleAir monitors, and (2) smoke density, obtained from the NOAA Hazard Mapping System. We used a longitudinal repeated measures study design with an autoregressive linear mixed effects model to quantify the relationships between measures of short-term exposure and cognitive performance, overall and by age group.
Results. A 10 μg/m3 increase in daily average PM2.5 in the week prior to play was associated with 46.9 (95% CI: -92.9, -0.9) point decrease in Lumosity game score. The highest impacts were observed in the youngest (18-29) and oldest (70+) age groups. The presence of medium smoke density on the day of game play was associated with a significant decrease in score. No other measures of smoke density in the 2 weeks prior to play were associated with Lumosity performance. No associations between measures of sub-daily PM2.5 exposure and performance were observed.
Conclusions. Results indicate that increases in daily average PM2.5 can adversely impact cognitive flexibility. Short-term smoke exposure may also be associated with cognitive performance, but more research is needed to investigate this relationship. This abstract does not reflect EPA policy.