Dr. Hofman is the initiator and principal investigator of two population based, prospective cohort studies in the city of Rotterdam, the Netherlands: the Rotterdam Study and the Generation R study. Data-collection for these studies started in 1990 and 2002, respectively. These cohort studies have in common that they target multiple common diseases, have a very extensive and state-of-the-art assessment of the putative determinants of these diseases, and employ as much as possible new technologies to be applied in the setting of epidemiologic population studies.