1. Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Japan
2. Department of Orthopaedic Surgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Japan
3. 3rd Department of Internal Medicine, Hokkaido P.W.F.A.C Obihiro-Kosei General Hospital, Japan
4. Faculty of Health Sciences, Hokkaido University, Japan