1. Oxford Centre for Diabetes, Endocrinology and Metabolism, University of OxfordChurchill Hospital, Old Road, Headington, Oxford OX3 7LJ, UK
2. Division of Diabetes, Metabolism and Endocrinology, Lund University221 84 Lund, Sweden
3. Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical CenterDurham, NC 27704, USA