American Journal of Epidemiology Advance Access originally published online on June 2, 2006
American Journal of Epidemiology 2006 164(5):437-448; doi:10.1093/aje/kwj186
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Original Contribution |
Recent Exposure to Particulate Matter and C-reactive Protein Concentration in the Multi-Ethnic Study of Atherosclerosis
1 Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, MI
2 Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
3 Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, NY
4 Department of Pathology, University of Vermont, Burlington, VT
5 Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, MI
6 Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis, MN
7 Department of Environmental and Occupational Health Sciences, School of Public Health, University of Washington, Seattle, WA
8 Department of Biostatistics, School of Public Health, University of Michigan, Ann Arbor, MI
9 Department of Atmospheric Sciences, School of Engineering, University of Michigan, Ann Arbor, MI
Correspondence to Dr. Ana V. Diez Roux, Department of Epidemiology, 1214 South University, Second Floor, Ann Arbor, MI 48103 (e-mail: adiezrou{at}umich.edu).
Ambient levels of particulate matter have been linked to cardiovascular disease. The mechanisms mediating these associations are poorly understood. One candidate mechanism is inflammation. Using data from the Multi-Ethnic Study of Atherosclerosis (2000–2002), the authors investigated the relation between exposure to particulate matter of less than or equal to 2.5 µm in diameter (PM2.5) and C-reactive protein concentration in 5,634 persons aged 45–84 years who were free of cardiovascular disease. Data from US Environmental Protection Agency monitors were used to estimate PM2.5 exposures for the prior day, prior 2 days, prior week, prior 30 days, and prior 60 days. Only the 30-day and 60-day mean exposures showed a weak positive association with C-reactive protein, and confidence intervals were wide: relative increases in C-reactive protein per 10 µg/m3 of PM2.5 adjusted for person-level covariates were 3% (95% confidence interval (CI): –2, 10) for a 30-day mean and 4% (95% CI: –3, 11.0) for a 60-day mean. The means of 7-day, 30-day, and 60-day exposures were weakly, positively, and nonsignificantly associated with the odds of C-reactive protein of greater than or equal to 3 mg/liter: adjusted odds ratios were 1.05 (95% CI: 0.96, 1.15), 1.12 (95% CI: 0.98, 1.29), and 1.12 (95% CI: 0.96, 1.32), respectively. Slightly stronger associations were observed in persons without other risk factors for elevated C-reactive protein, but this heterogeneity was not statistically significant. The authors' results are not compatible with strong effects of particulate matter exposures on population levels of C-reactive protein.
air pollutants, environmental; cardiovascular diseases; inflammation
Abbreviations: CI, confidence interval; MESA, Multi-Ethnic Study of Atherosclerosis; PM2.5, particulate matter of less than or equal to 2.5 µm in diameter; PM10, particulate matter of less than or equal to 10 µm in diameter