[1] Leiden Univ, Med Ctr, Dept Publ Hlth & Primary Care, Leiden, Netherlands
[2] Univ Groningen, Univ Med Ctr Groningen, Dept Gen Practice Groningen, Inst Asthma & COPD, Groningen, Netherlands
[3] Chest Res Fdn, Pune, Maharashtra, India
[4] Univ Zurich, Epidemiol Biostat & Prevent Inst, Zurich, Switzerland
[5] Univ Med & Pharm, Ho Chi Minh City, Vietnam
[6] Univ Crete, Sch Med, Clin Social & Family Med, Iraklion, Greece
[7] Minist Hlth Kyrgyz Republ, Natl Ctr Cardiol & Internal Med, Bishkek, Kyrgyzstan
[8] Univ Plymouth, Fac Med & Dent, Plymouth, Devon, England
[9] Univ Groningen, Univ Med Ctr Groningen, Groningen, Netherlands
[10] Univ Washington, Sch Med, Dept Pediat, Seattle, WA 98195 USA
[11] Int Primary Care Resp Grp, London, England
[12] European Lung Fdn, Sheffield, S Yorkshire, England
[13] Imperial Coll London, London, England
[14] Makerere Univ, Coll Hlth Sci, Lung Inst, Kampala, Uganda
[15] Univ Copenhagen, Dept Publ Hlth, Res Unit Gen Practice, Copenhagen, Denmark
[16] Univ Copenhagen, Dept Publ Hlth, Sect Gen Practice, Copenhagen, Denmark
[17] Copenhagen Univ Hosp, Rigshosp, Dept Paediat & Adolescent Hlth, Juliane Marie Ctr,Global Hlth Unit, Copenhagen, Denmark
[18] Natl Ctr Smoking Cessat & Training, Dorchester, England
[19] Univ Edinburgh, Usher Inst Populat Hlth Sci & Informat, Edinburgh, Midlothian, Scotland
[20] Coventry Univ, Coventry, W Midlands, England
[21] Univ Minho, Sch Med, Braga, Portugal