The exposome at twenty: a personal account

Abstract Non-communicable diseases represent a major global health burden of the 21st century, being responsible for over 70% of deaths annually worldwide. Environmental exposures as a whole (ie, non-genetic) are the main contributors to these diseases, although the identification of many of the specific risk factors remains to be defined. The exposome encompasses the totality of environmental exposures throughout the lifespan. This fresh perspective encourages a more comprehensive approach to exposure assessment when seeking to establish exposure-disease associations. The fact a number of the technologies applied to the exposome measure events on the disease pathway provides the additional benefit of indicating the biological plausibility of such associations. This article provides a personal history of the exposome, which serves to highlight the reasons why an exposome was needed to complement the genome. The article closes with indications of future priorities: in particular, it is vital to remain focused on the overall prize of establishing etiology as a basis for preventive interventions that in turn lead to a reduction in morbidity and mortality.