1. Discipline of Public Health Medicine, School of Nursing and Public Health, University of KwaZulu-Natal, Durban, South Africa
2. KwaZulu-Natal Department of Health, G J Crookes Hospital, Pietermaritzburg, South Africa
3. Africa Health Research Institute, Durban, South Africa
4. DSI-MRC South African Population Research Infrastructure Network (SAPRIN), Durban, South Africa