Carotid Intima-Media Thickness and Long-Term Exposure to Traffic-Related Air Pollution in Middle-Aged Residents of Taiwan: A Cross-Sectional Study

Environ Health Perspect. 2015 Aug;123(8):773-8. doi: 10.1289/ehp.1408553. Epub 2015 Mar 20.


Background: Associations between long-term exposure to air pollution and carotid intima-media thickness (CIMT) have inconsistent findings.

Objectives: In this study we aimed to evaluate association between 1-year average exposure to traffic-related air pollution and CIMT in middle-aged adults in Asia.

Methods: CIMT was measured in Taipei, Taiwan, between 2009 and 2011 in 689 volunteers 35-65 years of age who were recruited as the control subjects of an acute coronary heart disease cohort study. We applied land-use regression models developed by the European Study of Cohorts for Air Pollution Effects (ESCAPE) to estimate each subject's 1-year average exposure to traffic-related air pollutants with particulate matter diameters ≤ 10 μm (PM10) and ≤ 2.5 μm (PM2.5) and the absorbance levels of PM2.5 (PM2.5abs), nitrogen dioxide (NO2), and nitrogen oxides (NOx) in the urban environment.

Results: One-year average air pollution exposures were 44.21 ± 4.19 μg/m3 for PM10, 27.34 ± 5.12 μg/m3 for PM2.5, and (1.97 ± 0.36) × 10-5/m for PM2.5abs. Multivariate regression analyses showed average percentage increases in maximum left CIMT of 4.23% (95% CI: 0.32, 8.13) per 1.0 × 10-5/m increase in PM2.5abs; 3.72% (95% CI: 0.32, 7.11) per 10-μg/m3 increase in PM10; 2.81% (95% CI: 0.32, 5.31) per 20-μg/m3 increase in NO2; and 0.74% (95% CI: 0.08, 1.41) per 10-μg/m3 increase in NOx. The associations were not evident for right CIMT, and PM2.5 mass concentration was not associated with the outcomes.

Conclusions: Long-term exposures to traffic-related air pollution of PM2.5abs, PM10, NO2, and NOx were positively associated with subclinical atherosclerosis in middle-aged adults.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Air Pollutants / toxicity*
  • Air Pollution / adverse effects
  • Carotid Intima-Media Thickness* / statistics & numerical data
  • Coronary Artery Disease / chemically induced
  • Coronary Artery Disease / epidemiology*
  • Cross-Sectional Studies
  • Environmental Exposure*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Models, Theoretical
  • Nitrogen Oxides / toxicity
  • Particle Size
  • Particulate Matter / toxicity
  • Seasons
  • Taiwan / epidemiology
  • Vehicle Emissions / toxicity*


  • Air Pollutants
  • Nitrogen Oxides
  • Particulate Matter
  • Vehicle Emissions