1. Admission and Documentation Service, University Hospital Complex of A Coruña Santiago de Compostela, Spain
2. Department of Preventive Medicine and Public Health, University of Santiago de Compostela, Santiago de Compostela, Spain
3. CIBER de Epidemiología y Salud Pública, CIBERESP, Santiago de Compostela, Spain
4. Service of Neumology, University Hospital Complex of Vigo, Vigo, Spain
5. Service of Neumology, Ourense Hospital Complex, Ourense, Spain
6. Service of Oncology, Puerta de Hierro University Hospital. Madrid, Spain
7. Service of Preventive Medicine, University Hospital Complex of Santiago de Compostela, Santiago de Compostela, Spain