1. Department of Epidemiology and Medical Statistics, Faculty of Public Health, College of Medicine, University of Ibadan, Ibadan, Nigeria
2. Department of Demography and Population Studies, School of Social Sciences, University of Witwatersrand, Johannesburg, South Africa
3. Department of Tropical Hygiene and Public Health, Medical Faculty, Heidelberg University, Heidelberg, Germany
4. Department of Public & Environmental Health, School of Medicine & Allied Health Sciences, University of The Gambia, Kanifing, Gambia