[Questionnaire survey on sleep habit of 3-year-old children in Asahikawa City].

The present study surveyed the sleep habits of 3-year-old children in Asahikawa city using questionnaires completed by a parent during children's medical check-ups. Questionnaires were collected from the parents of 404 children (209 males, 195 females; mean age, 3.1 years) enrolled in this survey.