[1] Cent Univ, Dept Pneumol, Teaching Hosp Asturias, Oviedo, Spain
[2] Univ Santiago Compostela, Dept Prevent Med & Publ Hlth, C San Francisco S-N, Santiago De Compostela 15782, Spain
[3] Consortium Biomed Res Epidemiol & Publ Hlth CIBER, Madrid, Spain
[4] Hlth Res Inst Santiago de Compostela, Inst Invest Sanitaria Santiago de Compostela, Santiago De Compostela, Spain
[5] Univ Teaching Hosp Complex Vigo, Dept Pneumol, Vigo, Spain
[6] Inst Invest Sanitaria Galicia Sur IISGS, PneumoVigol Res Grp 1, Southern Galician Inst Hlth Res, Vigo, Spain
[7] Univ Teaching Hosp Complex Ourense, Dept Pneumol, Orense, Spain
[8] Univ Clin Teaching Hosp Santiago de Compostela, Dept Pneumol, Santiago De Compostela, Spain
[9] Avila Hosp Complex, Dept Pneumol, Avila, Spain
[10] Univ A Coruna, Dept Pneumol, Teaching Hosp, La Coruna, Spain