1. Department of Public Health, Sefako Makgatho Health Sciences University, Ga-Rankuwa, Pretoria 0208, South Africa
2. Department of Periodontology and Community Dentistry, Faculty of Dentistry, College of Medicine, University of Ibadan, Ibadan 200212, Nigeria
3. Mental Health, Alcohol, Substance Use and Tobacco Research Unit, South African Medical Research Council, Pretoria 0001, South Africa
4. Africa Centre for Tobacco Industry Monitoring and Policy Research (ATIM), School of Health Systems and Public Health, University of Pretoria, Pretoria 0002, South Africa