1. Division of Medical Gastroenterology, Department of Internal Medicine, Sahlgrenska University Hospital, Gothenburg, Sweden;
2. Department of Internal Medicine and Clinical Nutrition, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden;
3. Department of Clinical Pathology and Genetics, Sahlgrenska University Hospital, Gothenburg, Sweden;
4. Department of Surgery, Sahlgrenska University Hospital, Gothenburg, Sweden