Presentation Abstract

Session: MP05-Young Investigator Finalists - EPI
Wednesday, Mar 23, 2011, 5:00 PM - 7:00 PM
Presentation: MP029 - Longitudinal and Cross-Sectional Associations between Fine Particulate Air Pollution and Intima-Medial Thickness of the Common Carotid Artery: The Multi-Ethnic Study of Atherosclerosis and Air Pollution
Location: MP029
Pres. Time: Wednesday, Mar 23, 2011, 5:00 PM - 7:00 PM
Category: +EPI - Environmental
Keywords: Subclinical atherosclerosis; Public health; Geographic Disparities in Health
Author(s): Sara D. Adar, Univ of Michigan, Ann Arbor, MI; Lianne Sheppard, Univ of Washington, Seattle, WA; Joseph F Polak, Tufts Univ-New England Medical Ctr, Boston, MA; Paul D Sampson, Univ of Washington, Seattle, WA; Ana Diez Roux, Univ of Michigan, Ann Arbor, MI; Matthew Budoff, Los Angeles Biomedical Res Inst, Los Angeles, CA; David Jacobs, Univ of Minnesota, Minneapolis, MN; R Graham Barr, Columbia Univ, New York, NY; Karol Watson, Univ of California, Los Angeles, Los Angeles, CA; Joel D Kaufman, Univ of Washington, Seattle, WA
Abstract: Background: Chronic exposures to fine particulate matter (PM2.5) have been linked to cardiovascular morbidity and mortality, possibly via accelerated atherosclerosis. Using common carotid artery intima-medial thickness (IMT) as a surrogate for atherosclerosis, we hypothesized that long-term PM2.5 concentrations would be associated with an increased IMT extent and rate of progression.
Methods: Participants of the Multi-Ethnic Study of Atherosclerosis, aged 45 to 84 years and without clinical cardiovascular disease at baseline, had two ultrasounds for IMT between 2000 and 2005 (mean follow-up: 2.8 years). Long-term PM2.5 concentrations were estimated for each participant over the year before baseline and the period between ultrasounds using a finely resolved spatio-temporal model, which incorporates cohort-specific air monitoring data and geographic variables. Cross-sectional and longitudinal associations among persons not on statin therapy were examined in a unified model of the log of IMT using generalized estimating equations, clustering on subject and adjusting for traditional risk factors including age, sex, race, smoking, and blood pressure. We also controlled for the six study centers (each in a different state) to examine the relationship of within-metropolitan area PM2.5 variation and IMT.
Results: Among 4,089 participants with an average IMT of 700 µm and mean rate of progression of 12 µm/year, we found that living in areas with higher long-term PM2.5 concentrations was associated with a greater IMT. Cross-sectionally, an inter-quartile increase of 2 µg/m3 in PM2.5 was associated with a 0.8% (95% CI: 0.3 to 1.3 %) increase in IMT. Overall, no association between PM2.5 and progression of IMT was found, but a strong and statistically significant association was found after control for center. A 2 µg/m3 increase in within-metropolitan area PM2.5 was associated with a 5.8% (95% CI: 3.0 to 8.7%) increase in IMT progression. These within-metropolitan area associations were generally consistent across center, with three of six areas meeting statistical significance.
Conclusions: Living in areas with higher PM2.5 was cross-sectionally associated with increased IMT. Gradients within metropolitan areas also were associated with increased IMT progression. Between-metropolitan area differences in PM2.5 were not related to IMT progression but such contrasts might be confounded by region or center-specific features. These findings suggest that long-term PM2.5 exposures may be associated with the acceleration of atherosclerosis, even at current levels, and support previously reported associations with clinical cardiovascular disease development.
Disclosures:   S.D. Adar: B. Research Grant; Significant; received research grants (or support on research grants) on related topics from the USEPA. L. Sheppard: B. Research Grant; Significant; received support on research grants on related topics from NIH.. J.F. Polak: None. P.D. Sampson: B. Research Grant; Significant; received support on research grants on related topics from HEI.. A. Diez Roux: None. M. Budoff: None. D. Jacobs: None. R. Barr: B. Research Grant; Significant; received research grants (or support on research grants) on related topics from the NIH.. K. Watson: None. J.D. Kaufman: B. Research Grant; Significant; received research grants (or support on research grants) on related topics from the NIH..