1. Division of Population Medicine School of Medicine Cardiff University Neuadd Meirionnydd, Heath Park Cardiff CF14 4YS U.K
2. Primary Care and Population Sciences University of Southampton Southampton U.K
3. Hull York Medical School Universities of York and Hull U.K
4. Harrogate and District NHS Foundation Trust Harrogate U.K
5. Nuffield Department of Primary Health Care Sciences University of Oxford Oxford U.K