title: Objectively-measured sleep and its association with adiposity and physical activity in a sample of Canadian children.
abstract: Cross-sectional associations between objectively-measured sleep duration, sleep efficiency and sleep timing with adiposity and physical activity were examined in a cohort of 567 children from Ottawa, Canada. Five-hundred and fifteen children (58.8% female; age: 10.0 ± 0.4 years) had valid sleep measurements and were included in the present analyses. Physical activity, sedentary time and sleep parameters were assessed over 7 days (actigraphy). Height, weight and waist circumference were measured according to standardized procedures. Percentage body fat was assessed using bioelectric impedance analysis. Light physical activity and sedentary time were greater in children with the shortest sleep durations (P < 0.0001), whereas children with the highest sleep efficiencies had lower light physical activity and more sedentary time across tertiles (P < 0.0001). In multivariable linear regression analyses, and after adjusting for a number of covariates, sleep efficiency was inversely related to all adiposity indices (P < 0.05). However, sleep duration and sleep timing were not associated with adiposity indices after controlling for covariates. Inverse associations were noted between sleep duration and light physical activity and sedentary time (P < 0.0001). Sleep efficiency (P < 0.0001), wake time and sleep timing midpoint (P < 0.05) were negatively associated with light physical activity, but positively associated with sedentary time. In conclusion, only sleep efficiency was independently correlated with adiposity in this sample of children. Participants with the shortest sleep durations or highest sleep efficiencies had greater sedentary time. More research is needed to develop better sleep recommendations in children that are based on objective measures of sleep duration, sleep efficiency and sleep timing alike.
authors.affiliation: Healthy Active Living and Obesity Research Group, Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada; School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada.
authors.forename: Jessica
authors.initials: J
authors.lastname: Mcneil
authors.forename: Mark S
authors.initials: MS
authors.lastname: Tremblay
authors.forename: Geneviève
authors.initials: G
authors.lastname: Leduc
authors.forename: Charles
authors.initials: C
authors.lastname: Boyer
authors.forename: Priscilla
authors.initials: P
authors.lastname: Bélanger
authors.forename: Allana G
authors.initials: AG
authors.lastname: Leblanc
authors.forename: Michael M
authors.initials: MM
authors.lastname: Borghese
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Chaput
mesh_terms: D056044:Actigraphy; D050154:Adiposity / Q000502:physiology*; D001827:Body Height; D001835:Body Weight; D002170:Canada; D002648:Child; D003430:Cross-Sectional Studies; D015444:Exercise / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D012044:Regression Analysis; D057185:Sedentary Behavior; D012890:Sleep / Q000502:physiology*; D013997:Time Factors; D055105:Waist Circumference
keywords: anthropometric measurements; exercise; sedentary behavior; sleep patterns