1. Department of Psychological Sciences, Birkbeck, University of London, London, UK
2. Department of Medical Statistics, London School of Hygiene and Tropical Medicine, London, UK
3. Warwick Medical School, University of Warwick, Coventry, UK
4. School for Policy Studies, University of Bristol, Bristol, UK
5. Faculty of Medicine & Health Sciences, University of Nottingham, Nottingham, UK
6. Sheffield Children’s NHS Foundation Trust, Sheffield, UK
7. Department of Social and Environmental Health Research, London School of Hygiene and Tropical Medicine, London, UK