[1] Univ West Indies, Caribbean Inst Hlth Res, Epidemiol Res Unit, 7 Ring Rd, Kingston 7, Jamaica
[2] Univ West Indies, Dept Basic Med Sci, Kingston, Jamaica
[3] Univ West Indies, Dept Pathol, Kingston, Jamaica
[4] Univ West Indies, Dept Surg Radiol Anaesthesia & Intens Care, Kingston, Jamaica
[5] Univ West Indies, Dept Community Hlth & Psychiat, Kingston, Jamaica