[1] Tokyo Metropolitan Kiyose Childrens Hosp, Dept Pediat Nephrol, Kiyose, Tokyo 2048567, Japan
[2] Wakayama Med Univ, Dept Pediat, Wakayama, Japan
[3] Kumamoto Hlth Sci Univ, Dept Fundamental Med, Kumamoto, Japan
[4] Hokkaido Univ, Grad Sch Med, Dept Pediat, Sapporo, Hokkaido, Japan
[5] Kobe Univ, Dept Pediat, Grad Sch Med, Kobe, Hyogo 657, Japan
[6] Fussa Hosp, Dept Pediat, Tokyo, Japan
[7] Tokyo Metropolitan Kiyose Childrens Hosp, Dept Clin Res, Tokyo, Japan
[8] Univ Tokyo, Grad Sch Med, Sch Hlth Sci & Nursing, Dept Biostat Epidemiol & Prevent Hlth Sci, Tokyo, Japan