Ambient Air Pollution and Atherosclerosis in Los Angeles Nino Künzli, Michael Jerrett, Wendy J. Mack, Bernardo Beckerman, Laurie LaBree, Frank Gilliland, Duncan Thomas, John Peters, and Howard N. Hodis Divisions of Environmental Health and Biostatistics, Department of Preventive Medicine, and Atherosclerosis Research Unit, Division of Cardiovascular Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California, USA Abstract Associations have been found between long-term exposure to ambient air pollution and cardiovascular morbidity and mortality. The contribution of air pollution to atherosclerosis that underlies many cardiovascular diseases has not been investigated. Animal data suggest that ambient particulate matter (PM) may contribute to atherogenesis. We used data on 798 participants from two clinical trials to investigate the association between atherosclerosis and long-term exposure to ambient PM up to 2.5 µm in aerodynamic diameter (PM2.5) . Baseline data included assessment of the carotid intima-media thickness (CIMT) , a measure of subclinical atherosclerosis. We geocoded subjects' residential areas to assign annual mean concentrations of ambient PM2.5. Exposure values were assigned from a PM2.5 surface derived from a geostatistical model. Individually assigned annual mean PM2.5 concentrations ranged from 5.2 to 26.9 µg/m3 (mean, 20.3) . For a cross-sectional exposure contrast of 10 µg/m3 PM2.5, CIMT increased by 5.9% (95% confidence interval, 1-11%) . Adjustment for age reduced the coefficients, but further adjustment for covariates indicated robust estimates in the range of 3.9-4.3% (p-values, 0.05-0.1) . Among older subjects ( 60 years of age) , women, never smokers, and those reporting lipid-lowering treatment at baseline, the associations of PM2.5 and CIMT were larger with the strongest associations in women 60 years of age (15.7%, 5.7-26.6%) . These results represent the first epidemiologic evidence of an association between atherosclerosis and ambient air pollution. Given the leading role of cardiovascular disease as a cause of death and the large populations exposed to ambient PM2.5, these findings may be important and need further confirmation. Key words: air pollution, atherosclerosis, particulate matter. Environ Health Perspect 113:201-206 (2005) . doi:10.1289/ehp.7523 available via http://dx.doi.org/ [Online 22 November 2004] Address correspondence to N. Künzli, Keck School of Medicine University of Southern California, Division of Environmental Health, 1540 Alcazar St. CHP 236, Los Angeles, CA 90033-9013 USA. Telephone: (323) 442-2870. Fax: (323) 442-3272. E-mail: kuenzli@usc.edu This work was supported in part by the National Institute on Aging [grants R01AG-13860 (Vitamin E Atherosclerosis Prevention Study) and R01AG-17160 (B-Vitamin Atherosclerosis Intervention Trial) ], the National Institute of Environmental Health Sciences (grants P30 ES07048, 5P01ES11627) , the Wright Foundation, the Hastings Foundation, and the Health Effects Institute. The authors declare they have no competing financial interests. Received 26 August 2004 ; accepted 22 November 2004. The full version of this article is available for free in HTML or PDF formats. |