1. Primary Care Unit, Public Health England, Gloucester Royal Hospital, Great Western Road, Gloucester GL1 3NN, UK
2. Centre for Primary Care and Public Health, Bart’s and the London School of Medicine and Dentistry, Queen Mary University, Yvonne Carter Building, 58 Turner Street, London E1 2AB, UK
3. Statistics Unit Public Health England, 61 Colindale Avenue, London NW9 5EQ, UK
4. Nuffield Department of Primary Care Health Sciences, University of Oxford, Radcliffe Primary Care Building, Radcliffe Observatory Quarter, Woodstock Rd, Oxford OX2 6GG, UK
5. Gloucestershire Hospitals NHS Foundation Trust, Great Western Road, Gloucester GL1 3NN, UK
6. Division of Population Medicine, Cardiff University School of Medicine, Neuadd Meirionnydd, Heath Park, Cardiff CF14 4YS, UK