1. Cochrane South Africa, South African Medical Research Council, Tygerberg 7505, South Africa
2. Department of Biochemistry and Microbiology, University of Zululand, KwaDlangezwa 3886, South Africa
3. Department of Biochemistry, North-West University, Mafikeng Campus, Mmabatho 2735, South Africa
4. Non-Communicable Diseases Research Unit, South African Medical Research Council, Tygerberg 7505, South Africa
5. Department of Physiology and Environmental Health, University of Limpopo, Sovenga 0727, South Africa
6. School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal, Durban 4000, South Africa