Associations of Air Pollution and Noise with Local Brain Structure in a Cohort of Older Adults.

Background: Despite the importance of understanding associations of air pollution and noise exposure with loss of neurocognitive performance, studies investigating these exposures and local brain structure are limited.
Objective: We estimated associations of residential air pollution and noise exposures with neurocognitive test performance and the local gyrification index (lGI), a marker for local brain atrophy, among older adults.
Methods: For n = 615 participants from the population-based 1000BRAINS study, based on the German Heinz Nixdorf Recall study, we assessed residential exposures to particulate matter ( PM 10 , PM 2.5 , PM 2.5 abs ), accumulation mode particle number ( PN AM ), and nitrogen oxides ( NO x , NO 2 ), using land-use regression and chemistry transport models. Weighted 24-h and nighttime noise were modeled according to the European noise directive. We evaluated associations of air pollution and noise exposure at the participants' 2006-2008 residential addresses with neurocognitive test performance and region-specific lGI values ( n = 590 ) from magnetic resonance imaging, both assessed in 2011-2015, using linear regression and adjusting for demographic and personal characteristics.
Results: Air pollution and noise were associated with language and short-term/working memory and with local atrophy of the fronto-parietal network (FPN), a functional resting-state network associated with these cognitive processes. For example, per 2 - μ g / m 3 PM 10 , local brain atrophy was more pronounced in the posterior brain regions of the FPN, with a - 0.02 [95% confidence interval (CI): - 0.04 , 0.00] lower lGI. In contrast, in the anterior regions of the FPN, weighted 24-h and nighttime noise were associated with less local brain atrophy [e.g., 0.02 (95% CI: 0.00, 0.04) for 10  dB (A) 24-h noise].
Conclusions: Air pollution and noise exposures were associated in opposite directions with markers of local atrophy of the FPN in the right brain hemisphere in older adults, suggesting that both chronic air pollution and noise exposure may influence the physiological aging process of the brain. https://doi.org/10.1289/EHP5859.