This questionnaire is similar to the questionnaires used in the great population cohorts Malmö Diet and Cancer Study (MDCS, general population from Malmö, N = 28 000), and Malmö Offspring Study (MOS) (general population from Malmö, children and grandchildren to participants in MDCS, calculated to include 5000 participants, started 2013, supported by grants from VR). It is also used in a newly started endoscopy study where all consecutive patients performing a colonoscopy at the Department of Gastroenterology in Malmö will be included (calculated to include 2000 participants). The questionnaire contains questions about socioeconomic factors, life style factors (including diet, smoking, stuff use, alcohol habits, physical activity), medical health, drug consumption, heredity factors and gastrointestinal symptoms.