[1] Univ W Indies, Res Inst Trop Med, Epidemiol Res Unit, Kingston 7, Jamaica
[2] Purdue Univ, Dept Psychol Sci, W Lafayette, IN 47907 USA
[3] Inst Child Hlth, London, England
[4] Univ Maryland, Dept Pediat, College Pk, MD 20742 USA
[5] Harvard Univ, Sch Med, Childrens Hosp Boston, Boston, MA USA
[6] Univ Calif Davis, Dept Nutr, Davis, CA 95616 USA
[7] ICDDR B, Child Dev Unit, Dhaka B, Bangladesh
[8] Univ Michigan, Ctr Human Growth & Dev, Dept Pediat, Ann Arbor, MI 48109 USA
[9] Univ W Indies, Caribbean Child Dev Ctr, Kingston 7, Jamaica
[10] Univ Liverpool, Inst Psychol Hlth & Soc, Liverpool L69 3BX, Merseyside, England
[11] Univ Witwatersrand, ZA-2050 Johannesburg, South Africa