1. Medical Clinic and Policlinic IV, Ludwig Maximilian University of Munich, 80336 Munich, Germany
2. Division of Endocrinology, Diabetes and Clinical Nutrition, University Hospital of Zurich, Raemistrasse 100, CH-8091 Zurich, Switzerland
3. Institute for Automation and Systems Engineering, Ilmenau University of Technology, 98684 Ilmenau, Germany