Ambient air pollution and atherosclerosis in Los Angeles

Environ Health Perspect. 2005 Feb;113(2):201-6. doi: 10.1289/ehp.7523.


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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Air Pollution* / adverse effects
  • Arteriosclerosis / epidemiology
  • Arteriosclerosis / etiology
  • Arteriosclerosis / pathology*
  • Carotid Arteries / diagnostic imaging
  • Carotid Arteries / pathology*
  • Cross-Sectional Studies
  • Environmental Monitoring
  • Epidemiological Monitoring
  • Female
  • Geographic Information Systems
  • Humans
  • Los Angeles / epidemiology
  • Male
  • Middle Aged
  • Particle Size
  • Risk Factors
  • Tunica Intima / diagnostic imaging
  • Tunica Intima / pathology
  • Tunica Media / diagnostic imaging
  • Tunica Media / pathology
  • Ultrasonography