Exposure to polybrominated biphenyl (PBB) associates with DNA methylation differences across the genome

Polybrominated biphenyl (PBB) is an endocrine-disrupting compound which was accidently added to the food supply in Michigan in the 1970’s. Highly exposed individuals and their children have numerous health problems, though the underlying mechanism behind these health problems remains unknown. Other endocrine-disrupting compounds have been linked to epigenetic differences, but no epigenetic studies have been done for PBB. In this study, DNA from the blood of individuals with PBB exposure from the Michigan PBB Registry was interrogated with the MethylationEPIC BeadChip (N = 659). Associations between each of the ~850,000 CpG sites and current, serum PBB levels were tested with a linear regression that controlled for age, sex, and cell type proportions. We show that exposure to PBB is associated with differences in epigenetic marks that suggest that it is acting similarly to estrogen and is associated with dysregulated immune system pathways. DNA methylation was assessed in peripheral blood from people exposed to polybrominated biphenyl (PBB). Peripheral blood DNA was extracted, bisulfite converted and genome-wide DNA methylation was interrogated using the HumanMethylationEPIC BeadChip (Illumina).