title: Ambient air pollution and atherosclerosis in Los Angeles.
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 microm 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 microg/m3 (mean, 20.3). For a cross-sectional exposure contrast of 10 microg/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 (greater than or equal to 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.
authors.affiliation: Division of Environmental Health, Department of Preventive Medicine, Atherosclerosis Research Unit, Keck School of Medicine, University of Southern California, Los Angeles, California 90033-9013, USA. kuenzli@usc.edu
authors.forename: Nino
authors.initials: N
authors.lastname: Künzli
authors.forename: Michael
authors.initials: M
authors.lastname: Jerrett
authors.forename: Wendy J
authors.initials: WJ
authors.lastname: Mack
authors.forename: Bernardo
authors.initials: B
authors.lastname: Beckerman
authors.forename: Laurie
authors.initials: L
authors.lastname: LaBree
authors.forename: Frank
authors.initials: F
authors.lastname: Gilliland
authors.forename: Duncan
authors.initials: D
authors.lastname: Thomas
authors.forename: John
authors.initials: J
authors.lastname: Peters
authors.forename: Howard N
authors.initials: HN
authors.lastname: Hodis
mesh_terms: D000328:Adult; D000397:Air Pollution / Q000009:adverse effects; D001161:Arteriosclerosis / Q000453:epidemiology / Q000209:etiology / Q000473:pathology*; D002339:Carotid Arteries / Q000000981:diagnostic imaging / Q000473:pathology*; D003430:Cross-Sectional Studies; D004784:Environmental Monitoring; D062665:Epidemiological Monitoring; D005260:Female; D040362:Geographic Information Systems; D006801:Humans; D015141:Los Angeles / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D010316:Particle Size; D012307:Risk Factors; D017539:Tunica Intima / Q000000981:diagnostic imaging / Q000473:pathology; D017540:Tunica Media / Q000000981:diagnostic imaging / Q000473:pathology; D014463:Ultrasonography