1 Department of Pediatrics, Nasu Red Cross Hospital, Ohtawara, Tochigi-ken, Japan.
2 Department of Pediatrics, Nasu Red Cross Hospital, Ohtawara, Tochigi-ken, Japan; Department of Pediatrics, Dokkyo Medical University School of Medicine, Mibu, Tochigi-ken, Japan.
3 Department of Pediatrics, Dokkyo Medical University School of Medicine, Mibu, Tochigi-ken, Japan.
4 Department of Public Health, Dokkyo Medical University School of Medicine, Mibu, Tochigi-ken, Japan.