1. Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany
2. German Center for Diabetes Research (DZD), Munich, 85764 Neuherberg, Germany
3. Department Fitness and Health, University Wuppertal, 42119 Wuppertal, Germany
4. Department of Endocrinology and Diabetology, Medical Faculty, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany