1. Department of Epidemiology and Medical Statistics, University of Ibadan, Ibadan, Nigeria
2. Department of Family Medicine, Cecilia Makiwane Hospital, Walter Sisulu University, East London, South Africa
3. Nigeria State Health Investment Project, Akure, Nigeria
4. Department of Health Sciences, University of Fort Hare, East London, South Africa
5. Department of Sociology, University of Fort Hare, East London, South Africa