[1] Univ Cologne, Klin & Poliklin Psychosomat & Psychotherapie, Cologne, Germany
[2] Krankenhaus Augustinerinnen, Klin Allgemeine Innere Med Gastroenterol & Infekt, Cologne, Germany
[3] Univ Cologne, Klin Gastroenterol & Hepatol, Cologne, Germany
[4] Univ Cologne, Inst Med Stat Informat & Epidemiol, Cologne, Germany