title: Systematic review of sedentary behavior and cognitive development in early childhood.
abstract: OBJECTIVE
  To comprehensively review observational and experimental studies examining the relationship between sedentary behavior and cognitive development during early childhood (birth to 5years).
  
  
  METHODS
  Electronic databases were searched in July, 2014 and no limits were imposed on the search. Included studies had to be peer-reviewed, published, and meet the a priori determined population (apparently healthy children aged birth to 5years), intervention (duration, types, and patterns of sedentary behavior), comparator (various durations, types, or patterns of sedentary behavior), and outcome (cognitive development) study criteria. Data extraction occurred in October and November 2014 and study quality and risk of bias were assessed in December 2014.
  
  
  RESULTS
  A total of 37 studies, representing 14,487 participants from nine different countries were included. Thirty-one studies used observational study designs and six studies used experimental study designs. Across study designs, increased or higher screen time (most commonly assessed as television viewing (TV)), reading, child-specific TV content, and adult-specific TV content had detrimental (negative) associations with cognitive development outcomes for 38%, 0%, 8%, and 25% of associations reported, respectively, and beneficial (positive) associations with cognitive development outcomes for 6%, 60%, 13%, and 3% of associations reported, respectively. Ten studies were moderate quality and 27 studies were weak quality.
  
  
  CONCLUSIONS
  The type of sedentary behavior, such as TV versus reading, may have different impacts on cognitive development in early childhood. Future research with reliable and valid tools and adequate sample sizes that examine multiple cognitive domains (e.g., language, spatial cognition, executive function, memory) are needed. Registration no. CRD42014010004.
authors.affiliation: Faculty of Physical Education and Recreation, University of Alberta, Edmonton, Alberta, Canada. Electronic address: vlcarson@ualberta.ca.
authors.forename: Valerie
authors.initials: V
authors.lastname: Carson
authors.affiliation: Faculty of Physical Education and Recreation, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Kuzik
authors.affiliation: Faculty of Physical Education and Recreation, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Stephen
authors.initials: S
authors.lastname: Hunter
authors.affiliation: Department of Psychology, University of Alberta, Edmonton, Alberta, Canada; Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Sandra A
authors.initials: SA
authors.lastname: Wiebe
authors.affiliation: Faculty of Physical Education and Recreation, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: John C
authors.initials: JC
authors.lastname: Spence
authors.affiliation: Department of Psychology, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Alinda
authors.initials: A
authors.lastname: Friedman
authors.affiliation: Healthy Active Living and Obesity Research Group, Children's Hospital of Eastern Ontario Research Institute, Ottawa, Ontario, Canada; Department of Pediatrics, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Mark S
authors.initials: MS
authors.lastname: Tremblay
authors.affiliation: John W. Scott Health Sciences Library, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Linda G
authors.initials: LG
authors.lastname: Slater
authors.affiliation: Deakin University, Centre for Physical Activity and Nutrition Research, School of Exercise and Nutrition Sciences, Victoria, Australia.
authors.forename: Trina
authors.initials: T
authors.lastname: Hinkley
mesh_terms: D002657:Child Development; D002675:Child, Preschool; D003071:Cognition; D005260:Female; D015438:Health Behavior; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D010290:Parents; D015995:Prevalence; D011932:Reading; D057185:Sedentary Behavior; D013690:Television
keywords: Child; Growth & development; Infant; Preschool; Reading; Television