1. Clinic of Endocrinology and Nephrology, Department of Internal Medicine, Neurology and Dermatology, University of Leipzig, Leipzig, Germany
2. Department of General, Visceral, and Vascular Surgery, Martin-Luther-University of Halle-Wittenberg, Halle/Saale, Germany
3. Department of Endocrinology & Metabolism and Division of Laboratory Research, University Hospital Essen, Essen, Germany