Aging
Association of Midlife Air Pollution Exposures and Residential Road Proximity with Cognitive Decline over 28 Years: The Atherosclerosis Risk in Communities (ARIC) Study Ziwei Song* Ziwei Song Katie Lynch Naa Adoley Parker-Allotey Erin E. Bennett Xiaohui Xu Eric A. Whitsel Richard Smith James D. Stewart Eun Sug Park Qi Ying Emma Stapp Melinda C. Power
Background: Limited research has explored the associations between midlife ambient air pollution exposures and cognitive decline, despite the potential etiologic relevance of midlife exposures. We therefore considered whether midlife exposure to air pollutants and traffic are associated with 28-year cognitive decline from mid- to late-life in the Atherosclerosis Risk in Communities (ARIC) study.
Methods: Our sample included Black and White ARIC participants from four sites, Forsyth County, North Carolina; Jackson, Mississippi; Washington County, Maryland; and the suburbs of Minneapolis, Minnesota, who were free of dementia and completed cognitive testing at Visit 2 (1990-1992). Participants were asked to complete 3 cognitive tests — Delayed Word Recall Test (DWRT), Digit Symbol Substitution Test (DSST), and Word Fluency Test (WFT) – at Visit 2, Visit 4 (1996-1998), Visit 5 (2011-2013), Visit 6 (2016-2017), and Visit 7 (2018-2019). At participant addresses, we estimated: [1] 1990-1992 average ambient air pollutant concentrations by combining output from the Community Multiscale Air Quality (CMAQ) chemical transport model fused with observed annual concentrations and [2] distance to major roads and road density within 500m radius as measures of traffic exposure. We used adjusted linear mixed-effects models to quantify associations between exposures and 28-year cognitive change.
Results: Among 12,700 eligible participants, median age was 57 years, 56.0% were female, 24.2% identified as Black, and 78.9% had attained at least a high school education at baseline. Higher levels of nitrates, copper, and lead were marginally associated with greater 28-year decline in DSST performance; no other exposures were associated with cognitive decline in adjusted models.
Conclusions: Higher midlife exposure to select components of airborne PM2.5 including neurotoxic trace metals may be linked to decline in processing speed.