[1] South African Med Res Council, Cochrane South Africa, POB 19070, ZA-7505 Tygerberg, South Africa
[2] North West Univ, Dept Biochem, Mafikeng Campus, ZA-2735 Mmabatho, South Africa
[3] Univ Zululand, Dept Biochem & Microbiol, ZA-3886 Kwa Dlangezwa, South Africa
[4] South African Med Res Council, Noncommunicable Dis Res Unit, ZA-7505 Tygerberg, South Africa
[5] Univ Limpopo, Dept Physiol & Environm Hlth, ZA-0727 Sovenga, South Africa
[6] Univ KwaZulu Natal, Sch Lab Med & Med Sci, ZA-4000 Durban, South Africa