Opportunities and challenges of molecular epidemiology

Epidemiology studies the distribution and variation in exposure and disease in populations. Molecular epidemiology does so by measuring exposure and disease at the deepest biological level. Such move required important changes at the methodological level as well as the conceptual level-notably, by developing the “meeting-in-the-middle” methodology and the concept of “exposome.” In this chapter, we discuss how molecular methodology offers an opportunity to reflect upon traditional problems, such as the use of statistical analyses and the interpretation of data, and the role of technology in the scientific process. These, in turn, raise new conceptual and practical challenges, for instance the need to reconceptualize productive causality, and to design public health policies in the light of the results of molecular epidemiology.