[1] Univ Manchester, ARC Epidemiol Unit, Manchester M13 9PT, Lancs, England
[2] Strangeways Res Labs, Cambridge, England
[3] Behring Hosp, Berlin, Germany
[4] Russian Acad Med Sci, Inst Rheumatol, Moscow 109801, Russia
[5] Royal Natl Hosp Rheumat Dis, Bath BA1 1RL, Avon, England
[6] Hosp Angra Heroismo, Azores, Portugal
[7] Hosp Gen Asturias, E-33006 Oviedo, Spain
[8] Univ Southampton, Southampton Gen Hosp, Southampton, Hants, England
[9] INSERM, U403, F-69008 Lyon, France
[10] Univ Hosp, Louvain, Belgium
[11] Univ Istanbul, Fac Med, Istanbul, Turkey
[12] Aker Hosp, Oslo, Norway
[13] Clin Internal Med, Jena, Germany
[14] Free Univ Berlin, Dept Radiol & Nucl Med, D-1000 Berlin, Germany
[15] Univ Siena, Inst Clin Med, I-53100 Siena, Italy
[16] Med Ctr, Warsaw, Poland
[17] Clin Hosp, Zagreb, Croatia
[18] Ruhr Univ Bochum, D-4630 Bochum, Germany
[19] Lund Univ, Malmo, Sweden
[20] Ctr Metab Bone Dis, Sheffield, S Yorkshire, England
[21] Med Acad Erfurt, Erfurt, Germany
[22] Hosp San Joao, Oporto, Portugal
[23] Children Mem Hlth Inst, Warsaw, Poland
[24] Univ Athens, Lab Res Musculoskeletal Syst, Athens, Greece
[25] Ctr Med Specialisee, Montceau Les Mines, France
[26] Inst Rheumat Dis, Piestany, Slovakia
[27] Inst Social Med, Lubeck, Germany
[28] Med Acad, Szczecin, Poland
[29] Erasmus Univ, Dept Epidemiol, Rotterdam, Netherlands
[30] Erasmus Univ, Dept Internal Med, Rotterdam, Netherlands
[31] Natl Inst Rheumatism & Physiotherapy, Budapest, Hungary
[32] Univ Madrid, Fac Med, Madrid 3, Spain
[33] Univ Aberdeen, Dept Med & Therapeut, Aberdeen, Scotland
[34] Humboldt Univ, Inst Diagnost Radiol, Berlin, Germany
[35] Univ Heidelberg, Inst Social Med, Heidelberg, Germany
[36] Charles Univ, Dept Internal Med, Prague, Czech Republic
[37] Univ Manchester, Sch Nursing Midwifery & Hlth Visiting, Manchester, Lancs, England
[38] Univ Hosp, Dept Med, Graz, Austria
[39] Royal Cornwall Hosp, Dept Rheumatol, Truro, Cornwall, England