1. Department of Endocrinology and Metabolism (F.B., L.T., E.D., F.A.-L., E.M.), University of Pisa, 56124 Pisa, Italy
2. Department of Clinical Medicine (L.B., M.L.T.), University of Insubria, 21100 Varese, Italy
3. the Unit of Epidemiology and Biostatistics (G.R.), Institute of Clinical Physiology, National Research Council (CNR), 56100 Pisa, Italy