[1] Univ Glasgow, Sect Publ Hlth & Hlth Policy, Div Community Based Sci, Glasgow, Lanark, Scotland
[2] Univ Liverpool, Sch Management, Liverpool L69 3BX, Merseyside, England
[3] Univ E Anglia, Sch Med Hlth Policy & Practice, Norwich NR4 7TJ, Norfolk, England
[4] WHO, Dept Injuries & Violence Prevent, CH-1211 Geneva, Switzerland
[5] Univ London, Inst Educ, Social Sci Res Unit, London WC1N 1AZ, England
[6] St Leonards City & Hackney Primary Care Trust, Child & Adolescent Serv, London, England
[7] London Sch Hyg & Trop Med, Publ Hlth Intervent Res Unit, Dept Epidemiol & Populat Hlth, London WC1, England