Exposure to Traffic Emissions and Fine Particulate Matter and Computed Tomography Measures of the Lung and Airways

BACKGROUND: Exposure to ambient air pollution has been associated with lower lung function in adults, but few studies have investigated associations with radiographic lung and airway measures. METHODS: We ascertained lung volume, mass, density, visual emphysema, airway size, and airway wall area by computed tomography (CT) among 2,545 non-smoking Framingham CT sub-study participants. We examined associations of home distance to major road and PM(2.5) (2008 average from a spatiotemporal model using satellite data) with these outcomes using linear and logistic regression models adjusted for age, sex, height, weight, census tract median household value and population density, education, packyears of smoking, household tobacco exposure, cohort, and date. We tested for differential susceptibility by sex, smoking status (former vs never), and cohort. RESULTS: The mean participant age was 60.1 y (standard deviation 11.9). Median PM(2.5) level was 9.7 μg/m(3) (interquartile range 1.6). Living < 100 m from a major road was associated with a 108 mL (95% CI 8, 207) higher lung volume compared to ≥ 400 m away. There was also a log-linear association between proximity to road and higher lung volume. There were no convincing associations of proximity to major road or PM(2.5) with the other pulmonary CT measures. In subgroup analyses, road proximity was associated with lower lung density among men, and higher odds of emphysema among former smokers. CONCLUSIONS: Living near a major road was associated with higher average lung volume, but otherwise we found no association between ambient pollution and radiographic measures of emphysema or airway disease.