title: Organized physical activity in young school children and subsequent 4-year change in body mass index.
abstract: OBJECTIVE
  To determine whether participation in organized outdoor team sports and structured indoor nonschool activity programs in kindergarten and first grade predicted subsequent 4-year change in body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) during the adiposity rebound period of childhood.
  
  
  METHODS
  Longitudinal cohort study.
  
  
  METHODS
  Forty-five schools in 13 communities across Southern California.
  
  
  METHODS
  Largely Hispanic and non-Hispanic white children (N = 4550) with a mean (SD) age at study entry of 6.60 (0.65) years.
  
  
  METHODS
  Parents completed questionnaires assessing physical activity, demographic characteristics, and other relevant covariates at baseline. Data on built and social environmental variables were linked to the neighborhood around children's homes using geographical information systems.
  
  
  METHODS
  Each child's height and weight were measured annually during 4 years of follow-up.
  
  
  RESULTS
  After adjusting for several confounders, BMI increased at a rate 0.05 unit/year slower for children who participated in outdoor organized team sports at least twice per week compared with children who did not. For participation in each additional indoor nonschool structured activity class, lesson, and program, BMI increased at a rate 0.05 unit/year slower, and the attained BMI level at age 10 years was 0.48 units lower.
  
  
  CONCLUSIONS
  Engagement in organized sports and activity programs as early as kindergarten and the first grade may result in smaller increases in BMI during the adiposity rebound period of childhood.
authors.affiliation: Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles 90033-9045, USA. dunton@usc.edu
authors.forename: Genevieve
authors.initials: G
authors.lastname: Dunton
authors.forename: Rob
authors.initials: R
authors.lastname: McConnell
authors.forename: Michael
authors.initials: M
authors.lastname: Jerrett
authors.forename: Jennifer
authors.initials: J
authors.lastname: Wolch
authors.forename: Claudia
authors.initials: C
authors.lastname: Lam
authors.forename: Frank
authors.initials: F
authors.lastname: Gilliland
authors.forename: Kiros
authors.initials: K
authors.lastname: Berhane
mesh_terms: D001823:Body Composition; D001827:Body Height; D015992:Body Mass Index; D001835:Body Weight; D002140:California; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D050177:Overweight / Q000453:epidemiology; D012574:Schools; D013177:Sports / Q000502:physiology*; D011795:Surveys and Questionnaires