1. Department of Public Health, Faculty of Medicine, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany.
2. German Diabetes Center, Institute of Biometrics and Epidemiology, Düsseldorf, Germany.
3. Department of Epidemiology & International Public Health, School of Public Health, Bielefeld University, Bielefeld, Germany.
4. Institute of Epidemiology and Medical Biometry, Faculty of Medicine, University of Ulm, Ulm, Germany.
5. Children's Hospital, Hospitals of the City of Cologne, Cologne, Germany.
6. Department of Pediatrics and Adolescent Medicine, University Hospital of Schleswig-Holstein, Lübeck, Germany.
7. Catholic Children's Hospital Wilhelmstift, Hamburg, Germany.
8. University Clinic and Policlinic for Children and Adolescents, University Hospital of Leipzig, Leipzig, Germany.