Association between Fine Particulate Matter Exposure and Cerebrospinal Fluid Biomarkers of Alzheimer's Disease among a Cognitively Healthy Population-Based Cohort.

BACKGROUND

Epidemiological evidence suggests air pollution adversely affects cognition and increases the risk of Alzheimer's disease (AD), but little is known about the biological effects of fine particulate matter (, particulate matter with aerodynamic diameter ) on early predictors of future disease risk.

OBJECTIVES

We investigated the association between 1-, 3-, and 5-y exposure to ambient and traffic-related and cerebrospinal fluid (CSF) biomarkers of AD.

METHODS

We conducted a cross-sectional analysis using data from 1,113 cognitively healthy adults (45-75 y of age) from the Emory Healthy Brain Study in Georgia in the United States. CSF biomarker concentrations of , tTau, and pTau, were collected at enrollment (2016-2020) and analyzed with the Roche Elecsys system. Annual ambient and traffic-related residential concentrations were estimated at a and resolution, respectively, and computed for each participant's geocoded address, using three exposure time periods based on specimen collection date. Associations between and CSF biomarker concentrations, considering continuous and dichotomous (dichotomized at clinical cutoffs) outcomes, were estimated with multiple linear/logistic regression, respectively, controlling for potential confounders (age, gender, race, ethnicity, body mass index, and neighborhood socioeconomic status).

RESULTS

Interquartile range (IQR; ) increases in 1-y [; 95% confidence interval (CI): , ] and 3-y (; 95% CI: , ) ambient exposures were negatively associated with CSF concentrations. Associations between ambient and were similar for 5-y estimates (; 95% CI: , 0.005). Dichotomized CSF variables revealed similar associations between ambient and . Associations with traffic-related were similar but not significant. Associations between exposures and tTau, pTau , or levels were mainly null.

CONCLUSION

In our study, consistent trends were found between 1-y exposure and decreased CSF , which suggests an accumulation of amyloid plaques in the brain and an increased risk of developing AD. https://doi.org/10.1289/EHP13503.