title: Associations of outdoor play and screen time with nocturnal sleep duration and pattern among young children.
abstract: OBJECTIVE
  Sleep duration and pattern have important implications for children's health. This study aims to investigate nocturnal sleep duration, sleep pattern and their relationships with outdoor play and screen time among children aged 2 to five years.
  
  
  METHODS
  The study used data from the Healthy Beginnings Trial undertaken in Sydney, Australia. Data on children's sleep, outdoor playtime and screen time were reported by mothers via face-to-face interviews when children were 2, 3.5 and five years old. Both cross-sectional and longitudinal analyses were conducted.
  
  
  RESULTS
  At age 2, 3.5 and five years, 497, 415 and 369 mother-child dyads participated. Significantly, there was an overall increase in children's nocturnal sleep duration, sleep latency and an earlier bedtime, and there was a decrease in the proportion of children who woke at night over time. Each additional hour of screen time was associated with three-minute (95% CI 0.6-5) shorter sleep, 1.6-minute (95% CI 0.59-2.63) longer sleep latency, four-minute (95% CI 1.8-6.0) later bedtime and less likely sleeping ≥10 hours per night with adjusted odds ratio 0.88 (95% CI 0.77-1.00), after controlling for mothers' demographics.
  
  
  CONCLUSIONS
  Among young children, screen time and outdoor playtime were associated with sleep duration and pattern. Reducing screen time and increasing outdoor playtime might help improving children's sleep.
authors.affiliation: Sydney School of Public Health, University of Sydney, Sydney, NSW, Australia.|Health Promotion Unit, Sydney Local Health District, Sydney, NSW, Australia.
authors.forename: Huilan
authors.initials: H
authors.lastname: Xu
authors.affiliation: Sydney School of Public Health, University of Sydney, Sydney, NSW, Australia.|Health Promotion Unit, Sydney Local Health District, Sydney, NSW, Australia.
authors.forename: Li Ming
authors.initials: LM
authors.lastname: Wen
authors.affiliation: Prevention Research Collaboration, Sydney School of Public Health, University of Sydney, Sydney, NSW, Australia.
authors.forename: Louise L
authors.initials: LL
authors.lastname: Hardy
authors.affiliation: Sydney School of Public Health, University of Sydney, Sydney, NSW, Australia.
authors.forename: Chris
authors.initials: C
authors.lastname: Rissel
mesh_terms: D002675:Child, Preschool; D003430:Cross-Sectional Studies; D015444:Exercise; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D012890:Sleep; D013685:Telecommunications
keywords: Nocturnal sleep duration; Outdoor play; Screen time and sleep pattern