1. Department of Internal and Integrative Medicine, Kliniken Essen-Mitte, Faculty of Medicine; University of Duisburg-Essen; Essen Germany
2. Tempelhof Colon Centre; St. Joseph's Hospital; Berlin Germany
3. Department of Surgery and Centre for Minimal Invasive Surgery, Kliniken Essen-Mitte; University of Duisburg-Essen; Essen Germany
4. Department of Pain Management; Krankenhaus St. Josef; Wuppertal Germany
5. Department of Community Health; National University; San Diego CA USA
6. Department of Internal and Complementary Medicine; Immanuel Hospital Berlin; Berlin Germany
7. Institute of Social Medicine, Epidemiology and Health Economics; Charité University Medical Centre; Berlin Germany
8. Department of Integrative Gastroenterology, Kliniken Essen-Mitte, Faculty of Medicine; University of Duisburg-Essen; Essen Germany