1. Department of Medicine III, University Hospital Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany
2. Department of Internal Medicine I, Division of Endocrinology and Diabetes, University Hospital, University of Würzburg, 97082 Würzburg, Germany
3. Institute of Clinical Chemistry and Laboratory Medicine, University Hospital Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany
4. Department of Hypertension, National Institute of Cardiology, 04-828 Warsaw, Poland
5. Department of Endocrinology, Diabetology and Clinical Nutrition, University Hospital Zurich (USZ) and University of Zurich (UZH), 8057 Zurich, Switzerland
6. Department of Medicine IV, University Hospital, Ludwig Maximilian University of Munich, 80539 Munich, Germany
7. Department of Internal Medicine, Radboud University Medical Center, 6500 HB Nijmegen, the Netherlands