Long-Term Outdoor Air Pollution and Global DNA Methylation in Circulating Monocytes

Air pollution exposures are associated with an increased risk of cardiovascular disease (CVD), and alteration in DNA methylation has been proposed to mediate this association. Global DNA hypomethylation has been associated with ischemic heart disease, atherosclerosis, and air pollution. Research thus far of the effect of air pollution on DNA methylation has been limited to studies using blood leukocytes. Since monocytes are key to progression of atherosclerosis, we examined the association between long-term exposure to particulate matter less than 2.5 µm in aerodynamic diameter (PM 2.5), oxides of nitrogen (NO x), and black carbon (BC) and global DNA methylation in circulating monocytes of 1,207 participants from the Multi-ethnic Study of Atherosclerosis (MESA). The median methylation values (log intensity ratio methylated:unmethylated) of probes mapped to long interspersed nucleotide elements (LINE-1) or Alu elements in the Infinium HumanMethylation450 BeadChip were used as measures of global DNA methyla...