[1] Univ Calif San Francisco, Sch Med, 363 Lexington St, San Francisco, CA 94110 USA
[2] Ctr Hlth Equ, Harare, Zimbabwe
[3] King Caesor Univ, Sch Med, Kampala, Uganda
[4] Univ Saskatchewan, Dept Community Hlth & Epidemiol, Saskatoon, SK, Canada
[5] Univ Minnesota, Sch Med, Minneapolis, MN USA