Exposome

Abstract: the broad sense of ‘non-genetic’. The exposome, therefore, complements the genome by providing a comprehensive description of lifelong exposure history. Remaining focused on the element of application (to epidemiology) is a key to ensuring that the exposome is translated from concept to utility for better delineating the causes and prevention of human disease. At the time of the original proposal, it was recognized that whereas exquisite tools had been developed to sequence the human genome and to interrogate individual susceptibility through genome-wide association studies (GWAS), there was a relative paucity of comparable tools, or indeed investment, in relation to exposure assessment. Given that cancer and other chronic diseases develop predominantly from a combination of environmental exposures played out on a particular genetic background, the inability to measure one part of the gene:environment combination with anything approaching the precision of the other will stymie progress. This becomes particularly acute as epidemiology aims to tease out relatively modest effect sizes associated with specific environmental exposures. This commentary seeks to further define the exposome and to describe how its realisation may be achieved in epidemiological studies. The commentary focuses on cancer but many of the concepts are applicable to other chronic diseases.

Abstract: Despite extensive evidence showing that exposure to specific chemicals can lead to disease, current research approaches and regulatory policies fail to address the chemical complexity of our world. To safeguard current and future generations from the increasing number of chemicals polluting our environment, a systematic and agnostic approach is needed. The "exposome" concept strives to capture the diversity and range of exposures to synthetic chemicals, dietary constituents, psychosocial stressors, and physical factors, as well as their corresponding biological responses. Technological advances such as high-resolution mass spectrometry and network science have allowed us to take the first steps toward a comprehensive assessment of the exposome. Given the increased recognition of the dominant role that nongenetic factors play in disease, an effort to characterize the exposome at a scale comparable to that of the human genome is warranted.