[1] Univ Barcelona, IDIBAPS, Hosp Clin, Resp Inst, Barcelona, Spain
[2] CIBER Enfermedades Resp, Barcelona, Spain
[3] Imperial Coll London, Natl Heart & Lung Inst, Airways Dis Sect, Asthma & COPD Grp, London, England
[4] European Resp Soc, Lausanne, Switzerland
[5] Otto Wagner Hosp, Dept Resp & Crit Care Med, Vienna, Austria
[6] Otto Wagner Hosp, Ludwig Boltzmann Inst COPD & Resp Epidemiol, Vienna, Austria
[7] Karolinska Inst, Sachs Childrens Hosp, Stockholm, Sweden
[8] Karolinska Inst, Inst Environm Med, Stockholm, Sweden
[9] Univ Amsterdam, Amsterdam Univ Med Ctr, Dept Resp Med, Amsterdam, Netherlands
[10] Univ Amsterdam, Amsterdam Univ Med Ctr, Emma Childrens Hosp, Pediat Resp Med, Amsterdam, Netherlands
[11] Univ Manchester, Manchester Univ NHS Fdn Trust, Manchester Acad, Hlth Sci Ctr, Manchester, Lancs, England
[12] Univ Manchester, Div Infect Immun & Resp Med, Manchester, Lancs, England
[13] Univ Gothenburg, Sahlgrenska Univ Hosp, Inst Med, COPD Ctr, Gothenburg, Sweden
[14] Univ Groningen, Univ Med Ctr Groningen, Groningen, Netherlands
[15] Imperial Coll London, Natl Heart & Lung Inst, Airways Dis Sect, Cell & Mol Biol Grp, London, England
[16] Univ Ghent, Ghent, Belgium