CHAMACOS: A Birth Cohort Study in an Immigrant Population

Abstract

Background. Epigenetic mechanisms may provide a link between environmental exposures and effects on children’s health and provide clues for possible interventions. Birth cohorts with repeated collection of biological material can allow for an evaluation of epigenetic changes from thein utero period through childhood. Aims.To describe the CHAMACOS birth cohort study and the use of measures of DNA methylation to link environmental exposures and child health. Methods.We enrolled 601 pregnant women primarily of Mexican origin and have followed their children (currently 12 years old). We measuredin uteroand child exposure to numerous environmental agents in stored biological samples. In blood samples collected from the cord (fetal blood) and from the child at age 9, we measured global and site-specific DNA methylation in by Illumina Infinium Human Methylation 450K BeadChips. Results. We have previously shown that exposure to various environmental agents have been related to fetal growth, neurodevelopment and obesity. We have now begun to examine whether epigenetic changes may mediate these associations. We observed that approximately 15.5% of all investigated CpG sites were differentially methylated between the fetal period and age 9. We also found a significant difference in methylation by sex. Markers of DNA methylation will be examined in relation to prenatal exposure to environmental pollutants and as mediators of children’s health. Conclusions.Birth cohort studies can allow for the investigation of the role of epigenetics in mediating the relationship of environmental exposures and health of children. Acknowledgements: This work was supported by PO1 ES009605 and R01 ES017054 from the NIEHS and R82670901, RD83171001, and RD83451301 from the U.S. EPA.