Influence Of Prenatal Mercury And Arsenic Exposure In Utero On Dna Methylation In Umbilical Cord Blood

Background: Mercury and arsenic are known developmental toxicants. Prenatal exposures are associated with adverse childhood health outcomes that could be in part mediated by epigenetic alterations or altered immune profiles. Objectives: To examine the association between prenatal mercury exposure, on both DNA methylation and white blood cell composition of cord blood, and evaluate the interaction with prenatal arsenic exposure. Methods: A total of 138 mother-infant pairs were included in this study. Postpartum maternal toenail mercury levels and prenatal maternal urinary arsenic concentrations were measured using inductively coupled plasma mass spectrometry. DNA methylation was assessed in newborn cord blood using the Illumina Infinium HumanMethylation450 array. White blood cell composition was estimated using reference methylomes of isolated leukocyte subtypes. Results: A doubling in toenail mercury concentration was associated with a 2.5% decrease (95% CI: 5.0%, 1.0%) in the estimated monocyte proportio...