Long-term exposure to ambient air pollution and epigenetic age acceleration in children.

Long-term exposure to ambient air pollution has been associated with epigenetic age acceleration (EAA) in adults, but its impact on children remains less understood. This study analyzed data from 457 children (mean age: 7.9 years) in the Project Viva cohort (2007-2010, eastern Massachusetts, USA). We calculated EAA from leukocytes: Horvath's Epigenetic Age Acceleration (HorvathEAA), Intrinsic Epigenetic Age Acceleration (IEAA), and Skin and Blood Epigenetic Age Acceleration (Skin&BloodEAA). We applied generalized additive models to evaluate associations of prior 365-day average and lifetime average exposure to PM2.5, NO2, and O3, and distance to major roadways with EAA. Results indicated that each interquartile range of prior 365-day average of PM2.5 corresponded with 0.26 years (95% CI: -0.49, -0.03) lower HorvathEAA, although it did not survive multiple testing adjustment. Similar patterns but with wider confidence intervals were observed for IEAA (-0.22, 95% CI: -0.44, 0.01) and Skin&BloodEAA (-0.04, 95% CI: -0.19, 0.11). No associations were observed of exposure to lifetime average PM2.5, prior-year or lifetime average NO2 or O3, or distance to major roadways with EAA. These findings suggest higher prior 365-day average PM2.5 exposure may relate to lower HorvathEAA in children.