45-OR: Newborn Adiposity and Cord Blood DNA Methylation—An Epigenome-Wide Association Study in HAPO with Validation in Gen3G

Abstract

Differential cord blood DNA methylation (cb DNAm) in response to hyperglycemia in pregnancy may be associated with neonatal adiposity, a risk factor for childhood obesity. The Hyperglycemia and Adverse Pregnancy Outcome (HAPO) Study enrolled a multiethnic cohort to evaluate glycemia in pregnancy and newborn adiposity measured by skinfold thicknesses. We conducted an epigenome-wide association study using HAPO as a discovery sample and performed a replication study in an independent cohort, Gen3G. We analyzed cb DNAm with Illumina EPIC arrays (791,359 CpG sites after QC) on 2712 HAPO samples. We assessed the association between sum of 3 skinfolds and cb DNAm using linear regression models adjusted for maternal and offspring covariates and cell counts. We identified 90 CpG sites after accounting for multiple testing (Bonferroni-adjusted p<0.05). Using these sites identified in HAPO, we conducted similar regression analyses in 139 Gen3G cb DNAm samples to replicate findings. Similar associations at 7 CpG sites were identified including loci near KLF7, which encodes a regulator of cell proliferation and inhibitor of adipogenesis, and IGF1R, which encodes a transmembrane receptor involved in cell growth and survival that binds IGF1 and insulin, the latter especially during fetal life. These findings support epigenetic mechanisms in the developmental origins of neonatal adiposity. Disclosure J.L.Josefson: None. A.Kuang: None. D.Scholtens: None. C.Allard: None. W.Lowe: None. M.Hivert: None. Funding National Institutes of Health (R01HD034243, R01DK118403)