1. Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo 060-8638, Japan
2. Sapporo Diabetes and Thyroid Clinic, Sapporo 060-0807, Japan
3. Kurihara Clinic, Sapporo 004-0053, Japan
4. Aoki Clinic, Sapporo 003-0023, Japan