[1] Univ St Andrews, Sch Math & Stat, St Andrews, Scotland
[2] Univ Essex, Sch Hlth & Social Care, Colchester, England
[3] Univ Cambridge, British Heart Fdn Cardiovasc Epidemiol Unit, Dept Publ Hlth & Primary Care, Cambridge, England
[4] Univ Cambridge, Victor Phillip Dahdaleh Heart & Lung Res Inst, Cambridge, England
[5] Univ Essex, Sch Hlth & Social Care, Colchester CO4 3SQ, England