1. College of Social Sciences, University of Glasgow , United Kingdom
2. Faculty of Pharmaceutical Sciences, University of Nigeria , Nsukka
3. Department of Public Health, York St John University , London , United Kingdom
4. Department of Demography and Population Studies, University of the Witwatersrand , Johannesburg , South Africa
5. Warwick Medical School, University of Warwick , Coventry
6. Nuffield Department of Population Health, University of Oxford , United Kingdom