[1] Kyoto Univ, Grad Sch Med, Dept Otolaryngol Head & Neck Surg, Sakyo Ku, 54 Syogoin Kawahara Cho, Kyoto 6508507, Japan
[2] Kyoto Univ, Grad Sch Med & Publ Hlth, Dept Pharmacoepidemiol, Sakyo Ku, YoshidaKonoecho, Kyoto 6068501, Japan
[3] Shizuoka Prefectural Gen Hosp, Dept Otolaryngol Head & Neck Surg, Aoi Ku, 4-27-1 Kita Ando, Shizuoka 4208527, Japan