[1] Univ Nottingham, Div Epidemiol & Publ Hlth, Fac Med, Nottingham, England
[2] Univ Nottingham, UK Ctr Tobacco & Alcohol Studies, Nottingham, England
[3] Cardiff Univ, Div Populat Med, Cardiff, Wales
[4] UCL, Res Dept Behav Sci & Hlth, London, England
[5] Univ York, Dept Hlth Sci, York, N Yorkshire, England
[6] Leeds Teaching Hosp, Dept Radiol, Leeds, W Yorkshire, England
[7] Nottingham Univ Hosp NHS Trust, Deaprtment Resp Med, Nottingham, England
[8] Univ Manchester, Div Infect Immun & Resp Med, Wythenshawe, England
[9] Univ Leeds, Inst Hlth Sci, Leeds, W Yorkshire, England
[10] Leeds Teaching Hosp, Res & Innivat CSU, Leeds, W Yorkshire, England
[11] Leeds Teaching Hosp, Dept Resp Med, Leeds, W Yorkshire, England