title: Systematic review of active commuting to school and childrens physical activity and weight.
abstract: BACKGROUND
  The recent decline in children's active commuting (walking or biking) to school has become an important public health issue. Recent programs have promoted the positive effects of active commuting on physical activity (PA) and overweight. However, the evidence supporting such interventions among schoolchildren has not been previously evaluated.
  
  
  METHODS
  This article presents the results of a systematic review of the association between active commuting to school and outcomes of PA, weight, and obesity in children.
  
  
  RESULTS
  We found 32 studies that assessed the association between active commuting to school and PA or weight in children. Most studies assessing PA outcomes found a positive association between active commuting and overall PA levels. However, almost all studies were cross-sectional in design and did not indicate whether active commuting leads to increased PA or whether active children are simply more likely to walk. Only 3 of 18 studies examining weight found consistent results, suggesting that there might be no association between active commuting and reduced weight or body mass index.
  
  
  CONCLUSIONS
  Although there are consistent findings from cross-sectional studies associating active commuting with increased total PA, interventional studies are needed to help determine causation.
authors.affiliation: Habitat Health Impact Consulting Corp., Calgary, Alberta, Canada.
authors.forename: Murray C
authors.initials: MC
authors.lastname: Lee
authors.forename: Marla R
authors.initials: MR
authors.lastname: Orenstein
authors.forename: Maxwell J
authors.initials: MJ
authors.lastname: Richardson
mesh_terms: D000293:Adolescent; D001642:Bicycling / Q000502:physiology / Q000706:statistics & numerical data*; D001835:Body Weight; D002648:Child; D002675:Child, Preschool; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009043:Motor Activity / Q000502:physiology; D050177:Overweight / Q000453:epidemiology* / Q000517:prevention & control*; D012574:Schools; D014186:Transportation / Q000379:methods; D016138:Walking / Q000502:physiology / Q000706:statistics & numerical data*