1 Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Kita 14, Nishi 5, Kita-ku, Sapporo 060-8648, Japan.
2 Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Kita 14, Nishi 5, Kita-ku, Sapporo 060-8648, Japan. Electronic address: anobuya@med.hokudai.ac.jp.