Prenatal and Childhood Traffic-Related Air Pollution Exposure and Telomere Length in European Children: The HELIX Project

Background: Telomere length is a molecular marker of biological aging. Objective: Here we investigated whether early-life exposure to residential air pollution was associated with leukocyte telomere length (LTL) at 8 y of age. Methods: In a multicenter European birth cohort study, HELIX (Human Early Life Exposome) (n = 1,396), we estimated prenatal and 1-y childhood exposure to nitrogen dioxide (N[O.sub.2]), particulate matter with aerodynamic diameter [less than or equal to]2.5 [micro]m ([PM.sub.2.5]), and proximity to major roads. Average relative LTL was measured using quantitative real-time polymerase chain reaction (qPCR). Effect estimates of the association between LTL and prenatal, 1-y childhood air pollution, and proximity to major roads were calculated using multiple linear mixed models with a random cohort effect and adjusted for relevant covariates. Results: LTL was inversely associated with prenatal and 1-y childhood N[O.sub.2] and [PM.sub.2.5] exposures levels. Each standard deviation (SD) increase in prenatal N[O.sub.2] was associated with a -1.5% (95% CI: -2.8, -0.2) change in LTL. Prenatal [PM.sub.2.5] was nonsignificantly associated with LTL (-0.7% per SD increase; 95% CI: -2.0, 0.6). For each SD increment in 1-y childhood N[O.sub.2] and [PM.sub.2.5] exposure, LTL shortened by -1.6% (95% CI: -2.9, -0.4) and -1.4% (95% CI: -2.9, 0.1), respectively. Each doubling in residential distance to nearest major road during childhood was associated with a 1.6% (95% CI: 0.02, 3.1) lengthening in LTL. Conclusion: Lower exposures to air pollution during pregnancy and childhood were associated with longer telomeres in European children at 8 y of age. These results suggest that reductions in traffic-related air pollution may promote molecular longevity, as exemplified by telomere length, from early life onward. https://doi.org/10.1289/EHP4148
Introduction In the recent update of the Global Burden of Disease, Injuries, and Risk Factor study, air pollution is ranked fifth on a list of the most influential factors affecting [...]