Epigenetics, Built Environment and Atopy

摘要

Rationale Accurate estimation of gestational age (GA) using DNA methylation (DNAm) of umbilical cord blood, a novel development, provides relevant information on developmental stage. Studies of environmental exposures on GA are plentiful, but not using DNAm GA. We evaluated associations between DNAm GA, environmental correlates of the built environment and atopy. Methods Cord blood samples from 145 selected participants in the Canadian Healthy Infant Longitudinal Development study were examined, together with allergy skin prick tests at age 1 year. Exposure to greenness using satellite imagery, and individual exposure estimates to air pollution using land use regression models were assessed at home addresses throughout pregnancy. Associations of air pollution and greenness with DNAm GA residuals were tested while adjusting for maternal and neonatal characteristics. We further examined whether sensitization related to these environmental factors and DNAm GA. Results The mean GA was 276 (SD: 7.9) days, and mean DNAm GA was 279(5.8) days. There was a significantly positive correlation between these measues (r=0.66; p<0.001). Prenatal exposure to greenness showed borderline association with DNAm GA acceleration (i.e., older DNAm GA than chronological GA) (0.6 days, 95% CI: [-.6; 1.8] for one IQR exposure increase). Conversely, DNAm GA deceleration (i.e., younger DNAm GA) was associated with air pollution exposure during the first trimester (-2.1 days (-4.8; 0.7] for a 10 u.g/m3 exposure increase). 29% of this atopy-enriched sub-cohort were sensitized to at least one of 10 allergens. DNAm GA was a strong predictor of decreased risk of sensitization (OR: 0.93, 95%CI: [0.88; 0.99]), while air pollution exposure modestly increased the risk of sensitization by 4% (p=0.1). Conclusion Our findings warrant in depth investigation of potential mediating role of DNA methylation on the association between allergic disorders and the built environment.