title: Nighttime sleep duration and externalizing behaviors of preschool children.
abstract: OBJECTIVE
  To examine how many hours preschool children in the United States sleep at night and to test the hypothesis that children with shorter nighttime sleep duration are more likely to exhibit externalizing behaviors.
  
  
  METHODS
  The Early Childhood Longitudinal Study-Birth Cohort is a nationally representative longitudinal cohort study that followed children born in 2001 through kindergarten. This cross-sectional study examines the preschool wave (n = ∼8950). We estimated nighttime sleep duration from parent's reports of their 4-year-old child's typical weekday bed and wake times. Parents rated their child on 6 different externalizing behaviors (overactivity, anger, aggression, impulsivity, tantrums, and annoying behaviors) on a scale from 1 through 5 using the Preschool and Kindergarten Behavior Scale-second edition. Multivariable regression analyses were used to examine the association between sleep duration and behavior scores and to control for possible confounders.
  
  
  RESULTS
  Results are weighted to total United States population, ∼3,895,100 children born in 2001. Mean sleep duration was 10.47 hours. Mean bedtime was 8:39 PM and wake time was 7:13 AM. The adjusted odds ratios for children sleeping <9.44 hours (1 standard deviation below the mean) versus those sleeping ≥9.44 hours for 6 different externalizing behavior outcomes were as follows: overactivity = 1.30 (95% confidence interval [CI], 1.03-1.65); anger = 1.40 (95% CI, 1.15-1.71); aggression = 1.81 (95% CI, 1.36-2.41); impulsivity = 1.44 (95% CI, 1.12-1.86); tantrums = 1.46 (95% CI, 1.16-1.85); and annoying behaviors = 1.40 (95% CI, 0.97-1.87).
  
  
  CONCLUSIONS
  Shorter nighttime sleep duration in preschool children is associated with higher likelihood of externalizing behavioral symptoms based on parental report.
authors.affiliation: Division of Developmental and Behavioral Pediatrics, Department of Pediatrics, University of Virginia, Charlottesville, VA 22903, USA. rebeccascharf@virginia.edu
authors.forename: Rebecca J
authors.initials: RJ
authors.lastname: Scharf
authors.forename: Ryan T
authors.initials: RT
authors.lastname: Demmer
authors.forename: Ellen J
authors.initials: EJ
authors.lastname: Silver
authors.forename: Ruth E K
authors.initials: RE
authors.lastname: Stein
mesh_terms: D002653:Child Behavior Disorders / Q000453:epidemiology*; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D012890:Sleep / Q000502:physiology*; D013997:Time Factors; D014481:United States / Q000453:epidemiology