The European Prospective Investigation into Cancer and Nutrition (EPIC) is an ongoing multi-centre prospective cohort study designed to investigate the relationship between nutrition and cancer, with the potential for studying other diseases as well. The study currently includes 519 978 participants (366 521 women and 153 457 men, mostly aged 35-70 years) in 23 centres located in 10 European countries, to be followed for cancer incidence and cause-specific mortality for several decades. At enrolment, which took place between 1992 and 2000 at each of the different centres, information was collected through a non-dietary questionnaire on lifestyle variables and through a dietary questionnaire addressing usual diet. Anthropometric measurements were performed and blood samples taken, from which plasma, serum, red cells and buffy coat fractions were separated and aliquoted for long-term storage, mostly in liquid nitrogen. To calibrate dietary measurements, a standardised, computer-assisted 24-hour dietary recall was implemented at each centre on stratified random samples of the participants, for a total of 36 900 subjects. EPIC represents the largest single resource available today world-wide for prospective investigations on the aetiology of cancers (and other diseases) that can integrate questionnaire data on lifestyle and diet, biomarkers of diet and of endogenous metabolism (e.g. hormones and growth factors) and genetic polymorphisms. First results of case-control studies nested within the cohort are expected early in 2003. The present paper provides a description of the EPIC study, with the aim of simplifying reference to it in future papers reporting substantive or methodological studies carried out in the EPIC cohort.

The ‘European Investigation into Cancer and Nutrition (EPIC)’ represents one of the main scientific activities of the EU program ‘Europe against Cancer’ and is a large-scale cohort study on diet and chronic diseases, especially cancer, with approximately 475,000 study participants. The German contribution amounted to 53,000 study participants recruited between 1994 and 1998. The study instruments of the baseline examination included self-administered questionnaires for optical reading, PC-guided interviews, and physical examinations. These instruments covered different aspects of lifestyle, with a particular focus on diet. In addition, about 95% of the participants provided 30 ml of blood. The blood was stored in liquid nitrogen for further use, preferentially in nested case-control studies. All interviews and examinations were conducted by trained interviewers in examination centers established for this study in local health offices. Every 2 years, a follow-up questionnaire is mailed to the study participants. The follow-up questionnaires will be used as the major source of outcome information and to update exposure information. The self-reported diseases are verified by medical data. In the future, record linkage with local cancer registries will help to support the identification and collection of incident cancer cases. Only an outline of hypotheses was formulated at the very beginning of EPIC in 1992. In the future, each etiological study will be based on detailed research hypotheses according to the existing knowledge and identified research gaps. These studies will be conducted on cancer at the international level and on non-cancer diseases at the national or local level.

Metal workers, machinists, transport equipment operators and miners are among the major occupations contributing to occupational bladder cancer in men in Western Europe. In this population one in 10 to one in 20 cancers of the bladder can be attributed to occupation.