Rapid DNA methylation changes after exposure to traffic particles

Andrea Baccarelli, Robert O. Wright, Valentina Bollati, Letizia Tarantini, Augusto A. Litonjua, Helen H. Suh, Antonella Zanobetti, David Sparrow, Pantel S. Vokonas, Joel Schwartz

Research output: Contribution to journalArticle


Rationale: Exposure to particulate air pollution has been related to increased hospitalization and death, particularly from cardiovascular disease. Lower blood DNA methylation content is found in processes related to cardiovascular outcomes, such as oxidative stress, aging, and atherosclerosis. Objectives: We evaluated whether particulate pollution modifies DNA methylation in heavily methylated sequences with high representation throughout the human genome. Methods: We measured DNA methylation of long interspersed nucleotide element (LINE)-1 and Alu repetitive elements by quantitative polymerase chain reaction-pyrosequencing of 1,097 blood samples from 718 elderly participants in the Boston area Normative Aging Study. We used covariate-adjusted mixed models to account for within-subject correlation in repeated measures. We estimated the effects on DNA methylation of ambient particulate pollutants (black carbon, particulate matter with aerodynamic diameter <2.5 μm [PM 25], or sulfate) in multiple time windows (4 h to 7 d) before the examination. We estimated standardized regression coefficients (β) expressing the fraction of a standard deviation change in DNA methylation associated with a standard deviation increase in exposure. Measurements and Main Results: Repetitive element DNA methylation varied in association with time-related variables, such as day of the week and season. LINE-1 methylation decreased after recent exposure to higher black carbon (β = -0.11; 95% confidence interval [CI], -0.18to -0.04; P = 0.002)and PM 25(β = -0.13;95%CI, -0.19 to -0.06; P <0.001 for the 7-d moving average). In two-pollutant models, only black carbon, a tracer of traffic particles, was significantly associated with LINE-1 methylation (b = -0.09; 95%CI, -0.17 to -0.01; P = 0.03). No association was found with Alu methylation (P > 0.12). Conclusions: We found decreased repeated-element methylation after exposure to traffic particles. Whether decreased methylation mediates exposure-related health effects remains to be determined.

Original languageEnglish
Pages (from-to)572-578
Number of pages7
JournalAmerican Journal of Respiratory and Critical Care Medicine
Issue number7
Publication statusPublished - Apr 1 2009


  • Air pollution
  • Epigenetic processes
  • Inhalation exposure
  • Interspersed repetitive sequences

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine
  • Critical Care and Intensive Care Medicine

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    Baccarelli, A., Wright, R. O., Bollati, V., Tarantini, L., Litonjua, A. A., Suh, H. H., Zanobetti, A., Sparrow, D., Vokonas, P. S., & Schwartz, J. (2009). Rapid DNA methylation changes after exposure to traffic particles. American Journal of Respiratory and Critical Care Medicine, 179(7), 572-578. https://doi.org/10.1164/rccm.200807-1097OC