1. University of Oxford; Nuffield Department of Primary Care Health Sciences; Oxford UK
2. University of Leeds; Academic Unit of Health Economics; 101 Clarendon Road Leeds UK LS29LJ
3. University of Oxford; Bodleian Health Care Libraries; Knowledge Centre, ORC Research Building, Old Road Campus Oxford Oxfordshire UK OX3 7DQ
4. Oxford University Hospitals NHS Trust; Clinical Biochemistry; Headington Oxford UK
5. University of Birmingham; Public Health, Epidemiology and Biostatistics; Edgbaston Birmingham UK B15 2TT
6. University of Southampton; Department of Surgery; Southampton General Hospital Tremona Road Southampton UK S0322AB