Aging
Association of tailpipe-related and non-tailpipe-related air pollution exposure with neuroimaging outcomes in the Chicago Health and Aging Project Ryan M. Andrews* Ryan Andrews Stephanie T. Grady Neelum T. Agarwal Todd L. Beck Klodian Dhana Denis Evans Pauline Maillard Sarah Rothbard Elizabeth A. Stuart Adam A. Szpiro Saarika Virkar Sara D. Adar Charles S. DeCarli Joel D. Kaufman Kumar B. Rajan Jennifer Weuve
Background: Long-term exposure to air pollution has been associated with MRI measures of brain injury and reduced cognitive ability. A major source of air pollution is vehicle traffic, which is modifiable. In this study, we estimated associations between four traffic-related air pollutants and five neuroimaging biomarkers.
Methods: We analyzed data from a subset (N=817; 61% female; 60% Black) of participants in the Chicago Health and Aging Project (1993-2012) who underwent a structural MRI scan between 2002-2012, which is when MRI scans were offered as part of the study. Using validated fine-scale spatiotemporal models, we predicted participant-level exposure to the tailpipe pollutants oxides of nitrogen (NOX) and nitrogen dioxide (NO2), plus the non-tailpipe pollutants copper and zinc found in coarse particulate matter (PM10-2.5,Cu and PM10-2.5,Zn, respectively) over the three years prior to each participants’ first MRI scan date. Using linear regression, we estimated cross-sectional, covariate-adjusted associations between each pollutant with total cerebral volume, total hippocampal volume, total lateral ventricle volume, total white matter hyperintensity volume, and cortical thickness. These models incorporated inverse probability weights to account for potential selection biases driven by differences between participants who did and did not undergo an MRI scan after being offered one.
Results: Exposure to NOX and NO2 was associated with smaller cortical thinning on average (-0.06 mm, 95% CI: -0.09 to -0.02 per 1 SD [7.8 ppb] NOX; -0.04 mm, 95% CI: -0.07 to -0.01 per 1 SD [2.7 ppb] NO2). All other estimated associations were consistent with no effect.
Conclusion: Overall, these results are not indicative of large adverse associations between traffic-related air pollution exposures and indicators of brain injury in this biracial cohort.