title: Physical Activity During the Early Years: A Systematic Review of Correlates and Determinants.
abstract: Being physically active during the early years (age 0-6 years) is vital for healthy development. Identifying correlates and determinants of physical activity (PA) is crucial to guide effective interventions. This systematic review synthesized studies investigating potential correlates and determinants of PA during the early years, accounting for different types of PA assessment.
  
  
  
  Nine electronic databases were searched from inception year (1900) until September 2014; data were analyzed/interpreted in April 2015. The following inclusion criteria were used: written in English, published in peer-reviewed journals, participants not in statutory/school education, and an observational design investigating associations between an exposure/variable, and a quantitative measure of PA. Correlates/determinants of total, moderate to vigorous, and light PA were reported using an ecologic model.
  
  
  
  Of 22,045 identified studies, 130 were included. All took place in high-income countries and few (6%) were of high quality. Correlates of total PA were sex (male, ++); parental PA (+); parental support (+); and time outdoors (+). Determinants of total PA were sex (+) and time spent playing with parents (+). The only correlate of moderate to vigorous PA was sex (male, ++). No determinants of moderate to vigorous or light PA were found. PA correlates/determinants were relatively consistent between objective and subjective PA measures.
  
  
  
  Numerous studies investigated potential correlates and determinants of PA, but overall quality was low. A small number of demographic/biological and social/cultural factors were associated with PA. There is a need for high-quality studies exploring correlates/determinants across all domains of the ecologic model.
authors.affiliation: School of Sport, Exercise and Health Sciences, Loughborough University, Leicestershire, United Kingdom; Bradford Institute for Health Research, Bradford, United Kingdom. Electronic address: daniel.bingham@bthft.nhs.uk.
authors.forename: Daniel D
authors.initials: DD
authors.lastname: Bingham
authors.affiliation: Centre for Diet and Activity Research (CEDAR), MRC Epidemiology Unit, University of Cambridge, Cambridge, United Kingdom.
authors.forename: Silvia
authors.initials: S
authors.lastname: Costa
authors.affiliation: Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia;
authors.forename: Trina
authors.initials: T
authors.lastname: Hinkley
authors.affiliation: Institute of Psychological Sciences, University of Leeds, West Yorkshire, United Kingdom.
authors.forename: Katy A
authors.initials: KA
authors.lastname: Shire
authors.affiliation: School of Sport, Exercise and Health Sciences, Loughborough University, Leicestershire, United Kingdom.
authors.forename: Stacy A
authors.initials: SA
authors.lastname: Clemes
authors.affiliation: Bradford Institute for Health Research, Bradford, United Kingdom.
authors.forename: Sally E
authors.initials: SE
authors.lastname: Barber
mesh_terms: D004777:Environment; D015444:Exercise / Q000502:physiology*; D005195:Family Relations; D006293:Health Promotion; D006801:Humans; D010290:Parents / Q000523:psychology*; D010809:Physical Fitness / Q000523:psychology*; D012737:Sex Factors