[1] Univ Washington, Dept Global Hlth, Seattle, WA 98195 USA
[2] Univ Washington, Dept Med, Seattle, WA USA
[3] Univ Washington, Dept Epidemiol, Seattle, WA 98195 USA
[4] Univ Washington, Dept Biostat, Seattle, WA 98195 USA
[5] Fred Hutchinson Canc Res Ctr, Div Publ Hlth Sci, Seattle, WA 98104 USA
[6] Univ Nairobi, Dept Obstet & Gynaecol, Nairobi, Kenya
[7] Univ Washington, Dept Psychol, Seattle, WA 98195 USA
[8] Fred Hutchinson Canc Res Ctr, Div Human Biol, Seattle, WA 98104 USA
[9] Copt Hosp, Nairobi, Kenya