Differential methylation patterns in cord blood associated with prenatal exposure to neighborhood crime: an epigenome-wide association study and regional analysis.

Abstract

Exposure to prenatal social stressors during pregnancy is associated with adverse birth outcomes and has been linked to epigenetic changes in DNA methylation (DNAm); however, less understood is the effect of neighborhood-level stressors like crime during pregnancy on offspring DNAm. Using data from the Newborn Epigenetic Study, we conducted epigenome-wide and regional analyses of the association between exposure to neighborhood crime and DNAm in offspring cord blood using Illumina's HumanMethylation450k BeadChip among 185 mother-offspring pairs. Prenatal exposure to neighborhood crime at the census block group level was mapped to participants' residential addresses during the gestational window from the date of last menstrual period to delivery. Models for the epigenome-wide and regional analyses were adjusted for maternal age, race/ethnicity, education, smoking, cell-type composition, and offspring sex. Genetic influence and gene expression enrichment were assessed using methylation quantitative trait loci (mQTLs) and expression quantitative trait methylation (eQTMs) analyses. Functional enrichment was determined using Gene Ontology and KEGG databases. We did not find evidence of epigenome-wide associations between prenatal neighborhood crime exposure and DNAm; however, we identified nine differentially methylated regions (DMRs) comprising 51 CpG sites associated with neighborhood crime. CpG sites within significant differentially methylated regions were associated with mQTLs at birth and eQTMs upon further examination. KEGG analysis identified a significant Th1 and Th2 cell differentiation pathway. Our results suggest potential links between prenatal neighborhood crime exposure and offspring DNAm; however, additional research is needed in larger cohorts across wider geographic areas to confirm our results.