1. Tromsø Endocrine Research Group (R.J., S.T.S., J.S., R.M.J., Y.F.), 9037 Tromsø, Norway
2. Division of Internal Medicine (R.J., S.T.S., J.S., R.M.J.), 9038 Tromsø, Norway
3. Department of Clinical Medicine, Department of Clinical Medicine (H.S.), 9037 Tromsø, Norway
4. Epidemiology of Chronic Diseases Research Group (I.N.), 9037 Tromsø, Norway
5. Division of Diagnostic Services (O.M.F., Y.F.), University Hospital of North Norway, 9038 Tromsø, Norway
6. Department of Community Medicine, Department of Medical Biology (Y.F.), UiT The Arctic University of Norway, 9037 Tromsø, Norway
7. Division of Head and Motion (M.Y.S.H.), Department of Rheumatology, Nordland Hospital, 8092 Bodø, Norway