1. Medizinische Klinik und Poliklinik IV, Klinikum der Universität, Ludwig-Maximilians-Universität München, Germany
2. Klinik für Endokrinologie, Diabetologie und Klinische Ernährung, Universitäts-Spital Zürich, Zürich, Switzerland
3. Department of Medicine III, University Hospital Carl Gustav Carus, Dresden, Germany
4. Institute of Clinical Chemistry and Laboratory Medicine, University Hospital Carl Gustav Carus, Dresden, Germany
5. Department of Internal Medicine I, Division of Endocrinology and Diabetes, University Hospital, University of Würzburg, Würzburg, Germany
6. Division of Internal Medicine and Hypertension, Department of Medical Sciences, University of Turin, Turin, Italy