[1] South African Med Res Council, Cochrane South Africa, POB 19070, ZA-7505 Cape Town, South Africa
[2] Stellenbosch Univ, Dept Global Hlth, Div Epidemiol & Biostat, Cape Town, South Africa
[3] Univ Warwick, Warwick Med Sch Populat Evidence & Technol, Coventry, W Midlands, England
[4] Univ Cape Town, Sch Publ Hlth & Family Med, Cape Town, South Africa