[1] Katholieke Univ Leuven, Dept Rehabil Sci, Leuven, Belgium
[2] ISGlobal, Barcelona, Spain
[3] Imperial Coll London, Natl Heart & Lung Inst, London, England
[4] Natl & Kapodistrian Univ Athens, Sotiria Gen Chest Hosp, Thorax Res Fdn, Dept Resp Med 1, Athens, Greece
[5] Univ Zurich, Epidemiol Biostat & Prevent Inst, Zurich, Switzerland
[6] Northumbria Univ Newcastle, Dept Sport Exercise & Rehabil, Newcastle Upon Tyne, England
[7] Robert Bosch Krankenhaus, Dept Clin Rehabil, Stuttgart, Germany
[8] German Ctr Lung Res DZL, Pulm Res Inst, Airway Res Ctr North ARCN, LungenClin Grosshansdorf, Grosshansdorf, Germany