Author(s): Krishnan RM, Adar SD, Szpiro AA, Jorgensen NW, Van Hee VC,
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Abstract OBJECTIVES: This study evaluated the association of long- and short-term air pollutant exposures with flow-mediated dilation (FMD) and baseline arterial diameter (BAD) of the brachial artery using ultrasound in a large multicity cohort. BACKGROUND: Exposures to ambient air pollution, especially long-term exposure to particulate matter <2.5 μm in aerodynamic diameter (PM(2.5)), are linked with cardiovascular mortality. Short-term exposure to PM(2.5) has been associated with decreased FMD and vasoconstriction, suggesting that adverse effects of PM(2.5) may involve endothelial dysfunction. However, long-term effects of PM(2.5) on endothelial dysfunction have not been investigated. METHODS: FMD and BAD were measured by brachial artery ultrasound at the initial examination of the Multi-Ethnic Study of Atherosclerosis. Long-term PM(2.5) concentrations were estimated for the year 2000 at each participant's residence (n = 3,040) using a spatio-temporal model informed by cohort-specific monitoring. Short-term PM(2.5) concentrations were based on daily central-site monitoring in each of the 6 cities. RESULTS: An interquartile increase in long-term PM(2.5) concentration (3 μg/m(3)) was associated with a 0.3\% decrease in FMD (95\% confidence interval [CI] of difference: -0.6 to -0.03; p = 0.03), adjusting for demographic characteristics, traditional risk factors, sonographers, and 1/BAD. Women, nonsmokers, younger participants, and those with hypertension seemed to show a greater association of PM(2.5) with FMD. FMD was not significantly associated with short-term variation in PM(2.5) (-0.1\% per 12 μg/m(3) daily increase [95\% CI: -0.2 to 0.04] on the day before examination). CONCLUSIONS: Long-term PM(2.5) exposure was significantly associated with decreased endothelial function according to brachial ultrasound results. These findings may elucidate an important pathway linking air pollution and cardiovascular mortality. TRIAL REGISTRATION: ClinicalTrials.gov NCT00005487. Copyright © 2012 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.
This article was published in J Am Coll Cardiol
and referenced in Journal of Environmental Analytical Chemistry