[1] Univ Tokyo, Grad Sch Med, Dept Metab Dis, Bunkyo Ku, Tokyo 113, Japan
[2] Univ Tokyo, Grad Sch Med, Dept Biostat Epidemiol & Prevent Hlth Sci, Tokyo, Japan
[3] Asahi Life Fdn, Inst Diabet Care & Res, Tokyo, Japan
[4] Nippon Express Hlth Insurance Soc, Tokyo, Japan
[5] Chiba Univ, Dept Med Genet, Chiba, Japan
[6] Kurume Univ, Sch Med, Div Endocrinol & Metab, Dept Med, Kurume, Fukuoka 830, Japan