[1] Paracelsus Private Med Univ, Dept Pulm Med, Salzburg, V6Z 1Y6, Austria
[2] Kaiser Permanente Ctr Hlth Res, N-5021 Portland, OR USA
[3] St Pauls Hosp, UBC ICapture Ctr CardioPulmonary Res, Vancouver, BC, Canada
[4] Haukeland Hosp, Dept Thorac Med, Bergen, Norway
[5] Jagiellonian Univ, Sch Med, Dept Pulm Dis, Krakow, 97201, Poland
[6] Univ London Imperial Coll Sci Technol & Med, London, England
[7] Oregon Hlth & Sci Univ, Portland, OR USA