[1] Univ Zambia, Sch Hlth Sci, Dept Pharm, Lusaka 110101, Zambia
[2] Univ Teaching Hosp, HIV & Womens Hlth Res Grp, Lusaka, Zambia
[3] Univ Zambia, Sch Med, Dept Obstet & Gynecol, Lusaka, Zambia
[4] Univ Witwatersrand, Sch Publ Hlth, Dept Epidemiol & Biostat, Johannesburg, South Africa
[5] Univ Zambia, Sch Publ Hlth, Dept Epidemiol & Biostat, Lusaka, Zambia
[6] Univ Teaching Hosp, Trop Gastroenterol & Nutr Grp, Lusaka, Zambia