1. Fundación María José Jove; Health Centre “El Castrillón”; A Coruña Spain
2. Division of Respiratory Medicine; Department of Pediatrics, Hospital Clínico San Carlos; Madrid Spain
3. Clinical Epidemiology and Biostatistics Research Group; Hospital Universitario A Coruña; A Coruña Spain
4. Division of Respiratory Medicine; Department of Pediatrics, Hospital Donostia; San Sebastian Spain
5. Health Centre “La Cuesta”; Tenerife Spain
6. Hospital San Jaime de Calella; Barcelona Spain
7. Health Centre of La Eliana; Valencia Spain
8. Health Centre Zona Centro; Badajoz Spain
9. Fundación María José Jove; A Coruña Spain
10. Department of Pediatric Pneumology; Hospital Nuestra Señora de las Nieves; Granada Spain
11. Department of Pediatric Pneumology; Hospital Son Espases; Palma de Mallorca Spain