Exposure to Traffic and Fine Particulate Matter and Aortic Calcium in the Framingham Offspring and Third Generation Cohorts

Background: Exposure to traffic and ambient air pollution is associated with an increased risk of cardiovascular disease, potentially through atherosclerosis promotion. Few studies have assessed associations of these exposures with thoracic aortic calcium (TAC) or abdominal aortic calcium (AAC), which are correlates of atherosclerosis. Objective: We assessed whether living close to a major road and residential exposure to fine particulate matter (PM2.5) were associated with TAC and AAC in a community-based Northeastern U.S. cohort. Methods: TAC was measured from 2002[[Unable to Display Character: –]]2005 and AAC up to two times (2002[[Unable to Display Character: –]]2005; 2008[[Unable to Display Character: –]]2011) among participants from the Framingham Offspring or Third Generation Cohorts. We first assessed associations of residential distance to a major road and PM2.5exposure (2003 annual average from a spatiotemporal model) with detectable aortic calcium. We used logistic regression for TAC and generalized estimating equations (logit link) for AAC. As aortic calcium scores were right-skewed, we next used linear regression models and mixed effects models to assess associations with log-transformed TAC and AAC, respectively, among participants with aortic calcium scores > 0 (95% CIs bootstrapped). We also assessed associations with AAC progression. Models were adjusted for demographic variables, individual and area-level markers of socioeconomic position and time. Results: Among 3518 participants with TAC or AAC measured, 52% had AAC measured twice. Mean age was 55.8 years; 50% female. There were no associations of distance to a major road or PM2.5 with detectable TAC or AAC, though some estimates were in the opposite direction than expected (Table). There were no associations with extent of TAC or AAC (Table), or with AAC progression. Conclusions: Proximity to a major road and PM2.5 were not associated with the presence or extent of aortic calcium, or with AAC progression in this cohort from a region with relatively low PM2.5levels. Future work should explore these associations in other populations. (C) 2016 by the American College of Cardiology Foundation and the American Heart Association, Inc.