1. Rheumatology Department; Hospital Universitari Sagrat Cor; Barcelona Spain
2. Aalborg University Hospital; Aalborg University; Aalborg Denmark
3. Rheumatology Department; Parc de Salut Mar; Barcelona Spain
4. Nuffield Department of Orthopaedics; Rheumatology and Musculoskeletal Sciences, Oxford National Institute for Health Research Musculoskeletal Biomedical Research Unit, University of Oxford; Oxford UK
5. Medical Research Council Lifecourse Epidemiology Unit; University of Southampton; Southampton UK
6. Musculoskeletal Research Unit and Red Tematica de Investigacion Cooperativa en Envejecimiento y Fragilidad; Parc de Salut Mar and Instituto de Salud Carlos III; Barcelona Spain
7. Grup de Recerca de Malalties Prevalents de l'Aparell Locomotor Research Group, Institut d'Investigacio en Atencio Primaria Jordi Gol Primary Care Research Institute; Universitat Autònoma de Barcelona; Barcelona Spain