1. Ospedale Policlinico San Martino, Genoa, Italy
2. Pediatric Pneumology, IRCCS-Istituto Giannina Gaslini, Genoa, Italy
3. Epidemiology and Biostatistics Service, IRCCS-Istituto Giannina Gaslini, Genoa, Italy
4. Pediatric Allergy, IRCCS-Istituto Giannina Gaslini, Genoa, Italy
5. Università Vita Salute San Raffaele, Milan, Italy
6. Pediatric Pneumology, IRCCS Istituto Giannina Gaslini, Genoa, Italy