1 Center for Postgraduate Education and Training, National Center for Child Health and Development (NCCHD), Tokyo, Japan.
2 Department of General Pediatrics and Interdisciplinary Medicine, National Center for Child Health and Development (NCCHD), Tokyo, Japan.
3 Department of General Pediatrics and Interdisciplinary Medicine, National Center for Child Health and Development (NCCHD), Tokyo, Japan. masuda-h@ncchd.go.jp.
4 Division of Palliative Medicine, National Center for Child Health and Development (NCCHD), Tokyo, Japan.
5 Division of Otorhinolaryngology, National Center for Child Health and Development (NCCHD), Tokyo, Japan.