1. Department of Pediatrics and Adolescent Medicine , Medical University Vienna , Waehringer Guertel 18-20, 1090 , Vienna , Austria .
2. Institute for Biometrics and Epidemiology, German Diabetes Centre, Leibniz Centre for Diabetes Research , Heinrich-Heine University Düsseldorf , Düsseldorf , Germany
3. German Center for Diabetes Research (DZD) , Munich-Neuherberg , Germany
4. University Children’s Hospital Tübingen , Tübingen , Germany
5. Women and Children’s Centre , University of Leipzig , Leipzig , Germany
6. Division of Endocrinology and Diabetes , RWTH Aachen University , Aachen , Germany
7. Landeskrankenhaus Villach , Abteilung für Kinder- und Jugendheilkunde , Villach , Austria
8. Department of Epidemiology and Medical Biometry, ZIBMT , University of Ulm , Ulm , Germany .
9. Department of Pediatrics and Adolescent Medicine , Medical University Vienna , Vienna , Austria