1. Pediatric Pulmonary Unit; Meyer Children's University Hospital; Florence Italy
2. Department of Medicine and Surgery; University of Parma; Parma Italy
3. Unit of Epidemiology; Health Agency of Tuscany; Florence Italy
4. Clinical Care and Management Innovation Research Area; Bambino Gesù Pediatric Hospital, IRCCS; Rome Italy
5. Unit of Epidemiology; Meyer Children's University Hospital; Florence Italy