1. Department of Medicine 1, University of Erlangen – Nuremberg, Germany
2. Institute of Employment Research, Nuremberg, Germany
3. Department of Medicine 6, Paracelsus Medical University, Nuremberg, Germany
4. Synlab, Weiden, Germany
5. Thuringia Clinics, Gastroenterology, Saalfeld, Germany
6. Department of Nutritional Medicine, Sachsenhausen University Hospital, Frankfurt/Main, Germany