1 Section Endocrinology and Diabetology, University Obesity Centre, University Hospital Hamburg-Eppendorf, Hamburg, Germany.
2 Institute for Endocrinology & Diabetes, University of Lübeck, Department of Internal Medicine 1, Endocrinology & Diabetes, University of Lübeck, Lübeck, Germany.
3 Department of Internal Medicine, Diabetes Centre, Gemeinschaftskrankenhaus Bonn, Bonn, Germany.