title: Longer sleep--slimmer kids: the ENERGY-project.
abstract: BACKGROUND
  Few studies have differentiated between weekday and weekend day sleep duration in their association with indicators of weight status in children. Therefore, we examined the association of week and weekend day sleep duration with indicators of body composition in 10-12 year old European school children.
  
  
  RESULTS
  Multi-level linear regression analysis was performed to examine the association between parent-reported week and weekend day sleep duration and objectively assessed child BMI and WC, adjusting for socio-demographic variables and energy balanced related behaviours EBRBs (i.e. dietary, physical and sedentary behaviour). Compared to sleeping 10 hrs/night or more, sleeping on average less than 10 hrs/night during weekdays was associated with higher BMI (for example, B = 0.86 and CI = [0.27;1.45] when sleeping ≤7 hrs) and WC (for example, B = 1.99 and CI = [0.32;3.65] when sleeping ≤7 hrs). Sleeping 9 hrs/night during weekend days, but not ≤8 hrs, was associated with higher WC (B = 0.66; CI = [0.04;1.28]) compared to sleeping more than 10 hrs/night. Average (week and weekend) sleep duration less than 10 hrs/night was associated with higher values for BMI (B = 0.98; CI = [0.24;1.73] and WC (B = 2.35; CI = [0.08;4.31]).
  
  
  CONCLUSIONS
  Weekday sleep duration seems more strongly associated with body composition in European school children than weekend day sleep duration. Promoting adequate sleep duration may contribute to healthy weight in children.
authors.affiliation: Department of Public and Occupational Health, VU University Medical Center, EMGO Institute for Health and Care Research, Amsterdam, The Netherlands. t.altenburg@vumc.nl
authors.forename: Teatske M
authors.initials: TM
authors.lastname: Altenburg
authors.forename: Mai J M
authors.initials: MJ
authors.lastname: Chinapaw
authors.forename: Elise T W
authors.initials: ET
authors.lastname: van der Knaap
authors.forename: Johannes
authors.initials: J
authors.lastname: Brug
authors.forename: Yannis
authors.initials: Y
authors.lastname: Manios
authors.forename: Amika S
authors.initials: AS
authors.lastname: Singh
mesh_terms: D001823:Body Composition / Q000502:physiology*; D015992:Body Mass Index; D002648:Child; D004734:Energy Metabolism / Q000502:physiology*; D005060:Europe; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D012737:Sex Factors; D012890:Sleep / Q000502:physiology*; D012959:Socioeconomic Factors; D013997:Time Factors; D055105:Waist Circumference / Q000502:physiology*