Chapter 1 Introduction

A major goal of public health research is the study of the complex mechanisms leading to the development of diseases in humans, and the identification of potentially modifiable risk factors that could be targeted to reduce the burden of diseases in the overall population or in specific subgroups at high risk. A considerable number of potentially modifiable risk factors have been thoroughly studied, including dietary constituents, environmental factors such as chemicals and pollutants, lifestyle, social, and other ecological factors. Nevertheless, throughout their lifetime, humans are exposed to hundreds of these factors, which jointly contribute to the development of a given disease with complex mechanisms that can also involve antagonistic or synergistic interactions. This complex set of exposure is commonly referred to as “exposome” (Vermeulen et al. 2020).

The exposome (from Vermeulen et al. 2020)

Figure 1.1: The exposome (from Vermeulen et al. 2020)

Even when restricting our focus on environmental exposures - a substantial component of the exposome - it is recognized that we are simultaneously exposed to hundreds of chemicals and pollutants. For example it has been shown that a given blood or urine sample taken from a random American will contain some concentration of at least 400 different chemicals. A group of 3 or more chemicals/pollutants, simultaneously present in nature or in the human body, is commonly defined as an environmental mixture.


Vermeulen, Roel, Emma L Schymanski, Albert-László Barabási, and Gary W Miller. 2020. “The Exposome and Health: Where Chemistry Meets Biology.” Science 367 (6476): 392–96.