1. Institute of Metabolism and Systems Research, College of Medical and Dental Sciences, University of Birmingham , Birmingham B15 2TT , UK
2. Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners , Birmingham B15 2TT , UK
3. Department of Endocrinology, Queen Elizabeth Hospital Birmingham , Birmingham B15 2WB , UK
4. Division of Endocrinology and Diabetes, University Hospital University Würzburg , Würzburg 97080 , Germany
5. Department of Diabetes and Endocrinology, University College London Hospital NHS Foundation Trust , London NW1 2BU , UK
6. Centre for Obesity and Metabolism, Department of Experimental and Translational Medicine, Division of Medicine, University College London , London WC1E 6BT , UK