[1] Univ Catania, Dept Med & Pediat Sci, Catania, Italy
[2] Univ Naples 2, Dept Pediat, Naples, Italy
[3] Univ Pavia, Dept Pediat, Fdn Sci Inst Recovery, I-27100 Pavia, Italy
[4] Univ Pavia, Policlin San Matteo, Cure Fdn, I-27100 Pavia, Italy
[5] Univ Messina, Dept Pediat Sci, Messina, Italy
[6] Univ Parma, Clin Pediat Unit, Dept Clin & Expt Med, I-43126 Parma, Italy