Division of Endocrinology, Metabolism and Diabetes, University of Colorado School of Medicine and VA Eastern Colorado Health Care System, Aurora, CO 80045, USA. Endocrinology and Diabetes Center, Maine Medical Center and Maine Medical Center Research Institute, Scarborough, ME 04101, USA. Department of Medicine, Duke University, Durham, NC 27713, USA. Division of Endocrinology, Gerontology and Metabolism, Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA. AdventHealth Translational Research Institute, Orlando, FL 32804, USA. National Institute of Diabetes and Digestive, and Kidney Diseases, Bethesda, MD 20892 (retired), USA. Division of Endocrinology, Diabetes and Metabolism, Tufts Medical Center, Boston, MA 02111, USA.