1. Department of Medical Oncology, Northern Centre for Cancer Treatment, Newcastle General Hospital Newcastle upon Tyne, UK
2. Institute of Health and Society, Medical School, University of Newcastle Newcastle upon Tyne, UK
3. Health Protection Agency, North East Health Protection Unit, Institute of Pathology, Newcastle General Hospital Newcastle upon Tyne, UK
4. Department of Orthopaedic Surgery, South Tees Hospital NHS Trust Middlesborough, UK
5. Center for the Evaluative Clinical Sciences, Department of Community & Family Medicine, Dartmouth Medical School Hanover, New Hampshire, USA