[1] Univ Tsukuba, Inst Clin Med, Dept Internal Med, Tsukuba, Ibaraki 305, Japan
[2] Kyoto Univ, EBM Res Ctr, Kyoto, Japan
[3] Kyoto Univ, Translat Res Ctr, Kyoto, Japan
[4] Univ Tokyo, Sch Med, Dept Biostat, Tokyo 113, Japan
[5] Nippon Med Sch, Dept Med 3, Tokyo 113, Japan
[6] Saitama Med Sch, Dept Med 4, Saitama, Japan
[7] Asahi Life Fdn, Inst Adult Dis, Tokyo, Japan