1. Department of Nutrition and Public Health , Faculty of Health and Sport Sciences, University of Agder, P.O. Box 422, 4604 Kristiansand , Norway
2. Norwegian National Advisory Unit on Rehabilitation in Rheumatology , Department of Rheumatology, Oslo , Norway
3. Co-Director Pain Centre Versus Arthritis and Director Advanced Pain Discovery Platform , Professor of Rheumatology, Academic Rheumatology, University of Nottingham, Nottingham, NG5 1PB , UK