[1] Erasmus MC, Dept Epidemiol, Dr Molewaterplein 50,Off NA29-09,POB 2040, NL-3000 CA Rotterdam, Netherlands
[2] Univ Cambridge, Dept Publ Hlth & Primary Care, Cardiovasc Epidemiol Unit, Cambridge, England
[3] London Sch Hyg & Trop Med, Dept Populat Hlth, London, England
[4] UCL, Ctr Longitudinal Studies, London, England
[5] Univ Oxford, Nuffield Dept Populat Hlth, Oxford, England