Background: Air pollution is linked to low lung function and to respiratory events, yet little is known of associations with lung structure.
Objectives: We examined associations of particulate matter (PM2.5, PM10) and nitrogen oxides (NOx) with percent emphysema-like lung on computed tomography (CT).
Methods: The Multi-Ethnic Study of Atherosclerosis (MESA) recruited participants (45–84 years of age) in six U.S. states. Percent emphysema was defined as lung regions < –910 Hounsfield Units on cardiac CT scans acquired following a highly standardized protocol. Spirometry was also conducted on a subset. Individual-level 1- and 20-year average air pollution exposures were estimated using spatiotemporal models that included cohort-specific measurements. Multivariable regression was conducted to adjust for traditional risk factors and study location.
Results: Among 6,515 participants, we found evidence of an association between percent emphysema and long-term pollution concentrations in an analysis leveraging between-city exposure contrasts. Higher concentrations of PM2.5 (5 μg/m3) and NOx (25 ppb) over the previous year were associated with 0.6 (95% CI: 0.1, 1.2%) and 0.5 (95% CI: 0.1, 0.9%) higher average percent emphysema, respectively. However, after adjustment for study site the associations were –0.6% (95% CI: –1.5, 0.3%) for PM2.5 and –0.5% (95% CI: –1.1, 0.02%) for NOx. Lower lung function measures (FEV1 and FVC) were associated with higher PM2.5 and NOx levels in 3,791 participants before and after adjustment for study site, though most associations were not statistically significant.
Conclusions: Associations between ambient air pollution and percentage of emphysema-like lung were inconclusive in this cross-sectional study, thus longitudinal analyses may better clarify these associations with percent emphysema.
1Department of Epidemiology, University of Michigan, Ann Arbor, Michigan, USA; 2Department of Environmental and Occupational Health Sciences, 3Department of Epidemiology, and 4Department of Medicine, University of Washington, Seattle, Washington, USA; 5Department of Radiology, University of Iowa, Iowa City, Iowa, USA; 6Department of Biostatistics, University of Washington, Seattle, Washington, USA; 7Center for Public Health Genomics, University of Virginia, Charlottesville, Virginia, USA; 8Institute for Translational Genomics and Population Sciences, Los Angeles BioMedical Research Institute at Harbor-UCLA Medical Center, Torrance, California, USA; 9Medical Genetics Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA; 10Department of Statistics, University of Washington, Seattle, Washington, USA; 11Core for Biomedical Studies, Seattle Children’s Research Institute, Seattle, Washington, USA; 12Department of Biostatistics, University of Michigan, Ann Arbor, Michigan, USA; 13Department of Medicine, and 14Department of Epidemiology, Columbia University Medical Center, New York, New York, USA
Recommended Citation:
Sara D. Adar,1 Joel D. Kaufman,2,et al. Air Pollution and Percent Emphysema Identified by Computed Tomography in the Multi-Ethnic Study of Atherosclerosis[J]. Environmental Health Perspectives,2015-01-01,Volume 123(Issue 2):144