1. Division of Endocrinology and Metabolism, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo 173-8606, Japan
2. Division of Metabolism, Department of Internal Medicine, Self-Defense Forces Central Hospital, Tokyo 154-8532, Japan
3. Department of Laboratory Medicine, Teikyo University School of Medicine, Tokyo 173-8606, Japan
4. Second Division, Department of Internal Medicine, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan
5. Department of Family and Community Medicine, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan