Prenatal phthalate exposure and cord blood DNA methylation

Abstract

The indiscriminate use of phthalate-containing products in daily life can adversely affect pregnant women and their children. Phthalate can modify DNA methylation in the cord blood of infants. Therefore, we examined the association between prenatal phthalate exposure and cord blood DNA methylation in a Korean birth cohort. Phthalate levels in maternal blood during late pregnancy and cord blood were measured and DNA methylation of cord blood was measured using the Illumina HumanMethylationEPIC BeadChip kit. The association between CpG methylation and phthalate levels was analyzed using the ‘limma’ package in R, adjusting for infant sex, maternal body mass index, current maternal smoking status, and estimated leukocyte composition. We used data from 274 samples for estimating mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP) and mono-(2-ethyl-5-hydroxyhxyl) phthalate (MEHHP) levels and 273 samples for estimating mono-n-butyl phthalate (MnBP) levels to determine maternal phthalate concentrations during late pregnancy. Additionally, 102 samples were analyzed for all three types of phthalates in the cord blood. The meta-analysis revealed significant associations between the CpG sites near the CHN2 and CUL3 genes and cord blood MEOHP and MnBP concentrations, respectively. However, the three maternal phthalate concentrations during late pregnancy showed no significant association with CpG sites. In conclusion, prenatal phthalate exposure is significantly associated with DNA methylation at several CpG sites.