[1] Harvard Univ, Sch Publ Hlth, Dept Nutr, Boston, MA 02115 USA
[2] Harvard Univ, Sch Publ Hlth, Dept Epidemiol, Boston, MA 02115 USA
[3] Harvard Univ, Sch Publ Hlth, Dept Biostat, Boston, MA 02115 USA
[4] Harvard Univ, Sch Publ Hlth, Ctr Biostat AIDS Res, Boston, MA 02115 USA
[5] Childrens Hosp, Sch Med, Dept Pediat & Child Hlth, Boston, MA 02115 USA
[6] Childrens Hosp, Div Gastroenterol & Nutr, Boston, MA 02115 USA
[7] United Nations Childrens Fund, Reg Off W & Cent Africa, Dakar, Senegal
[8] Univ Minnesota, Sch Med, Minneapolis, MN 55455 USA
[9] Muhimbili Univ Hlth & Allied Sci, Dept Microbiol & Immunol, Dar Es Salaam, Tanzania