1. Preventive Medicine and Public Health Teaching and Research Unit, Health Sciences Faculty Rey Juan Carlos University Alcorcón Spain
2. Department of Public Health & Maternal and Child Health, Faculty of Medicine Universidad Complutense de Madrid Madrid Spain
3. Respiratory Department, Hospital General Universitario Gregorio Marañón, Facultad de Medicina Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM) Madrid Spain
4. Faculty of Nursing, Physiotherapy and Podology Universidad Complutense de Madrid Madrid Spain