[1] Natl Ctr Child Hlth & Dev, Dept Social Med, Tokyo, Japan
[2] Univ Calif Los Angeles, Fielding Sch Publ Hlth, Dept Epidemiol, Los Angeles, CA USA
[3] Okayama Univ, Grad Sch Med Dent & Pharmaceut Sci, Dept Pediat, Okayama, Japan
[4] Natl Ctr Child Hlth & Dev, Dept Med Subspecialties, Div Infect Dis, Tokyo, Japan
[5] Univ Tennessee, Dept Microbiol Immunol & Biochem, Hlth Sci Ctr, Memphis, TN USA
[6] Hamamatsu Univ Sch Med, Dept Pediat, Shizuoka, Japan
[7] Univ Tokyo, Grad Sch Med, Dept Hlth Serv Res, Tokyo, Japan
[8] Univ Tokyo, Sch Publ Hlth, Dept Clin Epidemiol & Hlth Econ, Tokyo, Japan
[9] Tokyo Med & Dent Univ, Grad Sch Med & Dent Sci, Dept Hlth Policy & Informat, Tokyo, Japan