[1] Univ Genoa, Azienda Osped Univ San Martino, I-16132 Genoa, Italy
[2] Univ Genoa, Dept Internal Med, I-16126 Genoa, Italy
[3] IRCCS G Gaslini, Epidemiol & Stat Unit, Genoa, Italy
[4] IRCCS G Gaslini, Ctr Allerg Dis, Genoa, Italy
[5] Navy Med Serv, La Spezia, Italy