1 Pediatric Allergy and Pulmonology Section, Department of Pediatrics, Hospital Universitari Vall d'Hebron, Barcelona, Spain; Group of Evaluation of Health Determinants and Health Policies, Faculty of Medicine and Health Science, Universitat Internacional de Catalunya (UIC-Barcelona), Sant Cugat del Vallès, Spain. Electronic address: ana.diez@vallhebron.cat.
2 Group of Evaluation of Health Determinants and Health Policies, Faculty of Medicine and Health Science, Universitat Internacional de Catalunya (UIC-Barcelona), Sant Cugat del Vallès, Spain.