1. Department of Paediatric Endocrinology and Diabetology, Children's University Hospital Bonn , 53127 Bonn , Germany
2. Department of Neonatology and Paediatric Intensive Care, Children's University Hospital Bonn , 53127 Bonn , Germany
3. Department of Paediatrics and Adolescent Medicine I, Paediatric Endocrinology and Diabetes, University Hospital of Schleswig - Holstein, Campus Kiel/Christian-Albrechts University of Kiel , 24105 Kiel , Germany