[1] Jichi Med Univ, Jichi Childrens Med Ctr Tochigi, Dept Pediat Otolaryngol, Shimotsuke, Tochigi 3290498, Japan
[2] Nagasaki Univ, Dept Otolaryngol Head & Neck Surg, Sch Med, Nagasaki, Japan
[3] Jichi Med Univ, Dept Otolaryngol, Saitama Med Ctr, Shimotsuke, Japan
[4] Jikei Univ, Sch Med, Dept Otorhinolaryngol, Tokyo, Japan
[5] Natl Sendai Med Ctr, Dept Otorhinolaryngol, Sendai, Miyagi, Japan
[6] Kamide Ear Nose & Throat Clin, Tokyo, Japan
[7] Chiba Prefectural Univ Hlth Sci, Fac Hlth Care Sci, Dept Nutr, Chiba, Japan
[8] Showa Univ, Dept Otorhinolaryngol, Sch Med, Tokyo, Japan
[9] Sotobo Childrens Clin, Chiba, Japan
[10] Chiba Childrens Hosp, Div Otorhinolaryngol, Chiba, Japan
[11] Tohoku Univ, Sch Med, Dept Otorhinolaryngol Head & Neck Surg, Sendai, Miyagi, Japan
[12] Hamamatsu Univ Sch Med, Dept Otorhinolaryngol Head & Neck Surg, Hamamatsu, Shizuoka, Japan
[13] Kyoto Univ, Sch Publ Hlth, Dept Hlth Informat, Kyoto, Japan