[1] Univ Aberdeen, Ctr Acad Primary Care, Aberdeen AB25 2ZD, Scotland
[2] Res Real Life Ltd, Cambridge, England
[3] Ghent Univ Hosp, Dept Resp Med, Ghent, Belgium
[4] Erasmus MC, Dept Epidemiol, Rotterdam, Netherlands
[5] Erasmus MC, Dept Resp Med, Rotterdam, Netherlands
[6] Box Surg, Corsham, Wilts, England
[7] Univ Plymouth, Ctr Clin Trials & Hlth Res Translat & Stratified, Peninsula Sch Med, Plymouth PL4 8AA, Devon, England
[8] Univ Plymouth, Sch Dent, Plymouth PL4 8AA, Devon, England
[9] Hosp Univ Vall dHebron, Ciber Enfermedades Resp CIBERES, Dept Pneumol, Barcelona, Spain
[10] Univ & Gen Hosp, Cardiovasc & Thorac Dept, Pulm Unit, Verona, Italy