Environmental exposures and epigenetic alterations in common chronic diseases: insights and challenges

Exposure to environmental factors including contaminants and social conditions is implicated in a substantial proportion of common non-communicable diseases, and data from model systems repeatedly demonstrate that the process from environmental contributions to common chronic disease risk is mediated through maladaptive epigenetic responses. The field of environmental epigenetics leverages multiple disciplines to advance our understanding of environmental impacts on epigenomic processes to enhance etiologic investigation, guide biomarker discovery, and identify mechanisms of action that ultimately lead to behavioral and or therapeutic interventions. This article discusses examples of emerging research on the links between three common life course exposures linked to common non-communicable diseases, and their associated epigenetic modifications, with a major focus on DNA methylation-the most studied in humans. It also outlines current challenges when interpreting the accumulating body of knowledge, including the lack of consensus on regions reported to be targeted by these environmental exposures. Finally, given that the strongest predictors of epigenetic states are age and cell/tissue type, strategies to build novel platforms using existing technologies to surmount some of these challenges are discussed. Together, these advances in environmental epigenetics are paving the way for groundbreaking developments toward improved precision in developing prevention and intervention strategies to reduce common non-communicable disease morbidity and mortality.