Despite decades of research, the etiology of many diseases remains largely unknown. Evidence indicates that the origins of certain chronic diseases have both genetic and environmental components. Studies have suggested linkages between depression and heart disease, inadequate vitamin D and risk of stroke and heart disease, and a variety of occupational exposures and associated health outcomes. Also, the rates of certain diseases among immigrants change to match those of the population where they move, which suggests an environmental component of disease. To better define the study of this environmental component, a new term, "exposome," has arisen in the scientific literature. Success in mapping the human genome has generated considerable scientific interest in the complementary concept of the exposome - the totality of exposures over a lifetime that predispose and predict health effects in an individual. The exposome describes response to any and all insults from conception-injuries, irritations, stressors and traumas, including those from occupational and environmental sources. These include lifestyle and diet, which are likely (in combination with the genome) to have a significant role in the etiology of disease . Thus, research on the exposome may help understand the multitude of interactions leading to disease. Clearly, the exposome is a compelling topic for those whose objective is to prevent illnesses caused or exacerbated by workplace exposure, and it has the potential to be a major focus of research.