title: Poor toddler-age sleep schedules predict school-age behavioral disorders in a longitudinal survey.
abstract: OBJECTIVE
  Behavioral problems are often associated with poor sleep habits in children. We investigated whether undesirable toddler-age sleep schedules may be related to school-age behavioral problems.
  
  
  METHODS
  We analyzed the data of a nationwide longitudinal survey with available results from 2001 to 2011. The participants were 41,890 children. The predictors were waking time and bedtime at 2years of age, and the outcomes were assessed by determining the presence or absence of three attention problems and four aggressiveness problems at 8years of age. In logistic regression models with adjustments for confounding factors, we estimated odds ratios (ORs) and confidence intervals (CIs) for the association between toddler sleep schedules and behavior during primary-school age years.
  
  
  RESULTS
  The outcomes of attention problems and aggressiveness problems were observed in 1.7% and 1.2% of children, respectively, at 8years of age. The OR of an irregular or late morning waking time at 2years of age with the outcome of aggressiveness problems was 1.52 (95% CI, 1.04-2.22) in comparison to an early waking time. The OR of an irregular or late bedtime with attention problems was 1.62 (95% CI, 1.12-2.36), and the OR of an irregular or late bedtime with aggressiveness problems was 1.81 (95% CI, 1.19-2.77) in comparison to an early bedtime.
  
  
  CONCLUSIONS
  Poor toddler-age sleep schedules were found to predict behavioral problems during primary-school age years. Thus, good and regular sleep habits appear to be important for young children's healthy development.
authors.affiliation: Department of Child Neurology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences and Okayama University Hospital, Okayama, Japan. Electronic address: k_koba@md.okayama-u.ac.jp.
authors.forename: Katsuhiro
authors.initials: K
authors.lastname: Kobayashi
authors.affiliation: Department of Human Ecology, Okayama University Graduate School of Environmental and Life Science, Okayama, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Yorifuji
authors.affiliation: Department of Human Ecology, Okayama University Graduate School of Environmental and Life Science, Okayama, Japan.
authors.forename: Michiyo
authors.initials: M
authors.lastname: Yamakawa
authors.affiliation: Department of Child Neurology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences and Okayama University Hospital, Okayama, Japan.
authors.forename: Makio
authors.initials: M
authors.lastname: Oka
authors.affiliation: Department of Epidemiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan; Department of Child and Adolescent Psychiatry, Okayama Psychiatric Medical Center, Okayama, Japan.
authors.forename: Sachiko
authors.initials: S
authors.lastname: Inoue
authors.affiliation: Department of Child Neurology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences and Okayama University Hospital, Okayama, Japan.
authors.forename: Harumi
authors.initials: H
authors.lastname: Yoshinaga
authors.affiliation: Department of Epidemiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Doi
mesh_terms: D000374:Aggression; D001288:Attention; D002648:Child; D002653:Child Behavior Disorders / Q000209:etiology*; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D016017:Odds Ratio; D012890:Sleep; D011795:Surveys and Questionnaires
keywords: ADHD; Behavioral disorders; Children; Sleep habits; Survey