[1] UCL, Dept Epidemiol & Publ Hlth, Canc Res UK Hlth Behav Res Ctr, London, England
[2] Univ Med Ctr Gottingen, Dept Cardiol & Pneumol, Gottingen, Germany
[3] Primary Hlth Care Corp, Dept Serv Dev & Hlth Promot, Doha, Qatar
[4] Kings Coll London, Inst Psychiat, Natl Addict Ctr, UK Ctr Tobacco & Alcohol Studies, London WC2R 2LS, England
[5] Wandsworth Med Ctr, London, England
[6] Natl Ctr Smoking Cessat & Training, London, England