The Exposome: An Approach Toward a Comprehensive Study of Exposures in Disease

The exposome is defined as the exposures that “encompass [all the] life-course environmental exposures (including lifestyle factors) from the prenatal period onwards.” It is a grand idea analogous to the genome, the inherited entity passed from parents to offspring via DNA. The exposome, if made practical, may enhance the comprehensive investigation of environmental exposures, ultimately enabling for the discovery of nongenetic causes of disease. In this article, we discuss the evolution from traditional environmental epidemiology—focused on examining one or a handful of exposures at a time in association with phenotype, to the exposome research paradigm, focused on examining multiple exposures associated with phenotypes. We also discuss new measurement technologies to quantify the “external” and “internal” exposome, and analytical methods applied to exposomic research that are not covered in traditional exposure assessment and epidemiology curricula. As biology becomes higher in throughput, or if the exposome phenomena are realized, emphases will need to be on data analytic methods to enhance discovery of exposome factors in disease and intervention of not single but multiple interacting exposures simultaneously.