1. Gastrointestinal Surgery; University of Helsinki and Helsinki University Hospital; Helsinki Finland
2. Department of General Practice and Primary Health Care; Helsinki University Hospital; University of Helsinki; Helsinki Finland
3. Department of General Practice and Primary Health Care; University of Eastern Finland; Kuopio Finland
4. Research Department; The Social Insurance Institution of Finland; Turku Finland
5. Helsinki University Clinic of Gastroenterology; University of Helsinki; Helsinki Finland