title: Sleep characteristics of young children in Japan: internet study and comparison with other Asian countries.
abstract: BACKGROUND
  A recent international Internet-based study of young children (birth to 36 months) found that total sleep duration in Japan was the shortest among 17 countries/regions. The present study compared features of children's sleep in Japan relative to those in other Asian countries/regions.
  
  
  METHODS
  Parents of 872 infants and toddlers in Japan (48.6% boys), and parents of 20 455 infants and toddlers in 11 other Asian countries/regions (48.1% boys; China, Hong Kong, India, Indonesia, Korea, Malaysia, Philippines, Singapore, Taiwan, Thailand, and Vietnam) completed an Internet-based expanded version of the Brief Infant Sleep Questionnaire.
  
  
  RESULTS
  Young children in Japan exhibited significantly fewer nocturnal wakings and shorter daytime sleep in comparison with other Asian countries/regions. Although the former finding was apparent in all age groups, the reduced duration of daytime sleep in Japan was not present until after 3 months of age. Interestingly, sleep problems were reported by significantly fewer parents in Japan compared with those in other Asian countries/regions, although parents in Japan reported significantly more difficulty at bedtime.
  
  
  CONCLUSIONS
  The short sleep duration of young children in Japan is largely due to a relatively short duration of daytime sleep. Significant differences in sleep characteristics in Japan relative to other Asian regions were found primarily after 3 months of age. Future studies should further explore the underlying causes and the potential impacts of these sleep differences.
authors.affiliation: Tokyo Bay Urayasu/Ichikawa Medical Center, Urayasu, JapanSaint Joseph's University and Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USAAdler Center for Research in Child Development and Psychopathology, Department of Psychology, Tel Aviv University, Israel.
authors.forename: Jun
authors.initials: J
authors.lastname: Kohyama
authors.affiliation: Tokyo Bay Urayasu/Ichikawa Medical Center, Urayasu, JapanSaint Joseph's University and Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USAAdler Center for Research in Child Development and Psychopathology, Department of Psychology, Tel Aviv University, Israel.
authors.forename: Jodi A
authors.initials: JA
authors.lastname: Mindell
authors.affiliation: Tokyo Bay Urayasu/Ichikawa Medical Center, Urayasu, JapanSaint Joseph's University and Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USAAdler Center for Research in Child Development and Psychopathology, Department of Psychology, Tel Aviv University, Israel.
authors.forename: Avi
authors.initials: A
authors.lastname: Sadeh
mesh_terms: D000328:Adult; D001210:Asia, Southeastern; D002675:Child, Preschool; D003431:Cross-Cultural Comparison; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007564:Japan; D008297:Male; D012890:Sleep / Q000502:physiology*; D011795:Surveys and Questionnaires; D014851:Wakefulness