1. University of Duisburg-Essen; Department of Internal and Integrative Medicine, Kliniken Essen-Mitte, Faculty of Medicine; Am Deimelsberg 34a Essen Germany
2. Universitätsmedizin Rostock; Center of Internal Medicine; Rostock Germany
3. University of Duisburg-Essen; Department for Integrative Gastroenterology, Kliniken Essen-Mitte, Faculty of Medicine; Am Deimelsberg 34a Essen Germany 45276