1. Epidemiology Group; Institute of Applied Health Sciences; University of Aberdeen; Aberdeen UK
2. Nuffield Department of Population Health; University of Oxford; Oxford UK
3. Norwich Medical School; University of East Anglia; Norwich UK
4. Clinical Informatics; Department of Medicine; University of Cambridge; Cambridge UK
5. Norfolk and Norwich University Hospital; Norwich UK
6. Health Services Research Unit; Institute of Applied Health Sciences; University of Aberdeen; Aberdeen UK
7. Academic Department of Medicine for the Elderly; Aberdeen Royal Infirmary; NHS Grampian; Aberdeen UK