1. Obesity and Diabetes Clinical Research Section, Phoenix Epidemiology and Clinical Research Branch, Department of Health and Human Services National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health Phoenix Arizona USA
2. Endocrinology Division, Medicine Department Phoenix VA Health Care System Phoenix Arizona USA
3. Division of Endocrinology, Diabetology and Clinical Nutrition, Department of Internal Medicine 1 University of Kiel Kiel Germany
4. Clinical Core Laboratory National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health Bethesda Maryland USA
5. Department of Information Engineering University of Pisa Pisa Italy