Nutrition and cancer: background and rationale of the European Prospective Investigation into Cancer and Nutrition (EPIC).

The development of epidemiological research on diet and cancer during the last decades is discussed. Apart from some consistent data on the protection against several cancers conferred by a diet rich in fruits and vegetables, the results provided by retrospective case-control studies on diet and cancer remain contradictory on many important issues, and primarily on the relation between diet and breast cancer. The rationale is presented for setting up large prospective cohort studies combining epidemiological and laboratory methods in order to expand the presently limited knowledge of the role of nutrition and related factors in cancer etiology. The main features of the European Prospective Investigation into Cancer and Nutrition are outlined. The study is being carried out in seven European countries and it will collect data on diet, other lifestyle and environmental factors, anthropometry as well as biological samples in a cohort of about 400,000 healthy European adults. The subjects will be followed up to investigate the incidence of and mortality from cancer in relation to epidemiological data and biochemical markers.