1. Preventive Medicine and Public Health, Rey Juan Carlos University, 28922 Madrid, Spain
2. Maria Zambrano Program, European Union, Spain
3. CIBER of Respiratory Diseases (CIBERES), Instituto de Salud Carlos III, 28029 Madrid, Spain
4. Department of Preventive Medicine, Hospital Universitario Fundación Alcorcón, Universidad Rey Juan Carlos, 28922 Madrid, Spain