1. School of Animal, Plant and Environmental Sciences, Faculty of Science, and Wits Rural Knowledge Hub, Research Office, University of Witwatersrand, Johannesburg, South Africa
2. CU Population Center, Institute of Behavioural Science, Department of Sociology, University of Colorado Boulder, Boulder, USA
3. MRC/Wits Rural Public Health and Health Transitions Research Unit (Agincourt), School of Public Health, University of the Witwatersrand, Acornhoek, South Africa
4. South African Medical Research Council/Department of Science and Innovation, South African Population Research Infrastructure Network, Durban, South Africa