The need to include environment in understanding human disease led Christopher Wild to introduce the concept of the exposome in 2005 (Wild, 2005), which he defined as "encompassing life-course environmental exposures (including lifestyle factors), from the prenatal period onwards." The exposome is envisioned as a complement to the genome, where life course of exposure and interaction with the genome defines risk for disease development. Unlike the genome, exposures are transient and vary on both short- and long-term time scales, making quantitative assessment challenging. A more tangible definition of the exposome was proposed by Miller and Jones (2014): "The cumulative measure of environmental influences and associated biological responses throughout the lifespan, including exposures from the environment, diet, behavior, and endogenous processes." Exposures in this framework are not only limited to external chemicals, but also include processes internal to the body (host factors) and wider socioeconomic influences (Rappaport and Smith, 2010; Wild, 2012). Exposomics is the study of the exposome, of which untargeted chemical profiling methods play a key role in identifying exposures and providing measures of biological response.
References
Miller GW, Jones DP. The nature of nurture: refining the definition of the exposome. Toxicol Sci. 2014;137(1):1-2.
Rappaport SM, Smith MT. Epidemiology. Environment and disease risks. Science. 2010;330(6003):460-461.
Wild CP. Complementing the genome with an "exposome": the outstanding challenge of environmental exposure measurement in molecular epidemiology. Cancer Epidemiol Biomarkers Prev.2005;14(8):1847-1850.
Wild CP. The exposome: from concept to utility. Int J Epidemiol. 2012;41(1):24-32.