title: Inequality in the built environment underlies key health disparities in physical activity and obesity.
abstract: BACKGROUND
  Environmental factors are suggested to play a major role in physical activity (PA) and other obesity-related behaviors, yet there is no national research on the relationship between disparity in access to recreational facilities and additional impact on PA and overweight patterns in US adolescents.
  
  
  OBJECTIVE
  In a nationally representative cohort, we sought to assess the geographic and social distribution of PA facilities and how disparity in access might underlie population-level PA and overweight patterns.
  
  
  METHODS
  Residential locations of US adolescents in wave I (1994-1995) of the National Longitudinal Study of Adolescent Health (N = 20745) were geocoded, and a 8.05-km buffer around each residence was drawn (N = 42857 census-block groups [19% of US block groups]). PA facilities, measured by national databases and satellite data, were linked with Geographic Information Systems technology to each respondent. Logistic-regression analyses tested the relationship of PA-related facilities with block-group socioeconomic status (SES) (at the community level) and the subsequent association of facilities with overweight and PA (at the individual level), controlling for population density.
  
  
  METHODS
  Outcome measures were overweight (BMI > or = 95th percentile of the Centers for Disease Control and Prevention/National Center for Health Statistics growth curves) and achievement of > or = 5 bouts per week of moderate-vigorous PA.
  
  
  RESULTS
  Higher-SES block groups had a significantly greater relative odds of having 1 or more facilities. Low-SES and high-minority block groups were less likely to have facilities. Relative to zero facilities per block group, an increasing number of facilities was associated with decreased overweight and increased relative odds of achieving > or = 5 bouts per week of moderate-vigorous PA.
  
  
  CONCLUSIONS
  Lower-SES and high-minority block groups had reduced access to facilities, which in turn was associated with decreased PA and increased overweight. Inequality in availability of PA facilities may contribute to ethnic and SES disparities in PA and overweight patterns.
authors.affiliation: Department of Nutrition, School of Public Health, Carolina Population Center, Chapel Hill, NC 27516-3997, USA. gordon_larsen@unc.edu
authors.forename: Penny
authors.initials: P
authors.lastname: Gordon-Larsen
authors.forename: Melissa C
authors.initials: MC
authors.lastname: Nelson
authors.forename: Phil
authors.initials: P
authors.lastname: Page
authors.forename: Barry M
authors.initials: BM
authors.lastname: Popkin
mesh_terms: D000293:Adolescent; D015444:Exercise; D006801:Humans; D009765:Obesity / Q000453:epidemiology* / Q000209:etiology; D050177:Overweight; D012111:Residence Characteristics; D012959:Socioeconomic Factors; D014481:United States / Q000453:epidemiology