[1] Univ Limpopo, Dept Physiol & Environm Hlth, ZA-0727 Sovenga, South Africa
[2] South African Med Res Council, Noncommunicable Dis Res Unit, ZA-7505 Tygerberg, South Africa
[3] North West Univ, Dept Biochem, Mafikeng Campus, ZA-2735 Mmabatho, South Africa
[4] South African Med Res Council, Cochrane South Africa, ZA-7505 Tygerberg, South Africa
[5] Univ KwaZulu Natal, Sch Lab Med & Med Sci, ZA-4000 Durban, South Africa
[6] Univ Western Cape, Sch Publ Hlth, ZA-7535 Bellville, South Africa
[7] Univ Cape Town, Dept Med, ZA-7700 Cape Town, South Africa
[8] Univ Witwatersrand, Dept Internal Med, ZA-2050 Johannesburg, South Africa
[9] Univ Zululand, Dept Biochem & Microbiol, ZA-3880 Kwa Dlangezwa, South Africa