1. Division of Clinical Preventive Medicine, Department of Community Preventive Medicine, Niigata University Graduate School of Medical and Dental Sciences, Asahimachi 1-757, Chuo-ku, Niigata 951-8510
2. Department of Clinical Laboratory Medicine, Juntendo University School of Medicine, Hongo 2-1-1, Bunkyo-ku, Tokyo 113-8421
3. Division of Pediatrics
4. Division of Endocrinology and Metabolism, Department of Homeostatic Regulation and Development, Niigata University Graduate School of Medical and Dental Sciences, Asahimachi 1-757, Chuo-ku, Niigata 951-8510, Japan