[1] Univ Verona, Dipartimento Sanita Pubbl & Med Comunita, Sez Epidemiol & Stat Med, Unit Epidemiol & Med Stat,Ist Biol 2, IT-37134 Verona, Italy
[2] Univ Pavia, IRCCS San Matteo Hosp Fdn, Div Resp Dis, I-27100 Pavia, Italy
[3] Local Hlth Agcy Turin 2, Territorial Unit Pneumol B, Turin, Italy
[4] Univ Hosp Geneva, Div Pulm Med, Geneva, Switzerland
[5] Landspitali Univ Hosp, Dept Allergy Resp Med & Sleep, Reykjavik, Iceland
[6] Univ Bergen, Dept Thorac Med, Haukeland Univ Hosp, Bergen, Norway
[7] Univ Bergen, Inst Med, Bergen, Norway
[8] German Res Ctr Environm Hlth, Helmholtz Zentrum Munchen, Inst Epidemiol, Neuherberg, Germany
[9] Uppsala Univ, Dept Med Sci Resp Med & Allergol, Uppsala, Sweden
[10] Univ London Imperial Coll Sci Technol & Med, Natl Heart & Lung Inst, Resp Epidemiol & Publ Hlth Grp, London, England
[11] Tartu Univ Hosp, Lung Clin, Tartu, Estonia
[12] Ctr Hosp Univ Grenoble, Grenoble, France
[13] Inst Albert Bonniot, INSERM, U823, Grenoble, France
[14] Univ Grenoble 1, Grenoble, France