1. Department of Social Medicine and Public Health, Faculty of Health Sciences, Pomeranian Medical University, Szczecin, Poland
2. Gastroenterology Department, St John’s Hospital, Livingston, UK
3. Private Gastroenterology Office, Duesseldorf, Germany
4. Department of Gastroenterology, Skåne University Hospital, Lund University, Malmö, Sweden
5. Clinic for Internal Medicine, Agaplesion Bethesda Krankenhaus Bergedorf, 21029 Hamburg, Germany