1. Department of Public Health, Society and Environments, London School of Hygiene & Tropical Medicine, London, UK
2. Bristol Medical School, University of Bristol, Bristol, UK
3. Department of Medical Statistics, London School of Hygiene & Tropical Medicine, London, UK
4. Department of Applied Health Research, University College London, London, UK
5. School of Social Work, Care and Community, University of Central Lancashire, Preston, UK
6. School of Social Sciences, Cardiff University, Cardiff, UK
7. College of Medicine and Health, University of Exeter, Exeter, UK
8. NORC, University of Chicago, Chicago, IL, USA
9. Department of Health Behavior, University of North Carolina, Chapel Hill, NC, USA
10. Medical Research Council/Chief Scientist Office Social and Public Health Sciences Unit, University of Glasgow, Glasgow, UK
11. Institute for Social Marketing, University of Stirling, Stirling, UK