1. University of the West of England; Faculty of Health & Life Sciences; Courtyard Building, BRI Bristol UK BS2 8HW
2. Cardiff University School of Medicine; Section of Rheumatology, Division of Infection and Immunity; Tenovus Building Heath Park Cardiff UK CF14 4XN
3. University of Bristol, Bristol Royal Infirmary; Rheumatology Unit; The Courtyard Marlborough Street Bristol UK BS2 8 HW
4. Institute of Psychiatry, Psychology & Neuroscience, King's College London; Chronic Fatigue Service, Department of Psychological Medicine; Weston Education Centre Cutcombe Road London UK SE5 9RH
5. Copenhagen University Hospital, Bispebjerg og Frederiksberg; Musculoskeletal Statistics Unit, The Parker Institute; Nordre Fasanvej 57 Copenhagen Denmark DK-2000