1. Metabolism and Diabetes Unit, Regione Piemonte, Chieri, Italy
2. Division of Metabolic Diseases, University of Padua, Padua, Italy
3. National Institute of Health, Rome, Italy
4. University of Florence and Azienda Ospedaliera Careggi, Florence, Italy
5. Federico II University, Naples, Italy
6. Casa di Cura Pineta del Carso, Aurisina, Trieste, Italy
7. Department of Internal Medicine and Consiglio Nazionale delle Ricerche Institute of Clinical Physiology, University of Pisa School of Medicine, Pisa, Italy