[1] Univ Nairobi, Dept Paediat, Nairobi, Kenya
[2] Univ Washington, Dept Epidemiol, Seattle, WA 98195 USA
[3] Univ Washington, Dept Med, Seattle, WA USA
[4] Univ Colorado, Sch Med, Denver, CO USA
[5] Univ Washington, Dept Biostat, Seattle, WA 98195 USA
[6] Fred Hutchinson Canc Res Ctr, Div Human Biol, Seattle, WA 98104 USA
[7] Kenyatta Natl Hosp, Nairobi, Kenya