title: A multilevel study of the associations between economic and social context, stage of adolescence, and physical activity and body mass index.
abstract: OBJECTIVE
  Prevention efforts targeting adolescent risk behavior have had limited effectiveness, partly because of the reliance on individual-level interventions that do not consider the context within which behavior occurs. In addition, the role of development has not been well studied regarding its possible moderating effects on contextual influences on behavior. The purpose of this study was to examine the influence of economic and social context on the odds of being inactive or having above-normal weight and whether the influence differed on the basis of stage of adolescence.
  
  
  METHODS
  Analysis used a subset of adolescents aged 10 to 17 years from the National Survey of Children's Health (n = 37930) from all states and the District of Columbia (n = 51). Dependent variables included physical activity and BMI. State-level economic context was measured by the proportion of families living below 200% of the federal poverty level. Social context was measured by aggregated means of responses to 2 indicators of social capital: mutual aid and social trust. Multilevel modeling was conducted to investigate associations between state-level economic and social context and physical activity and BMI, while controlling for individual sociodemographic characteristics, and whether these associations were dependent on an individual's stage of adolescence.
  
  
  RESULTS
  Both state-level mutual aid and social trust were significantly related to the odds of an adolescent not meeting current physical activity recommendations, yet state-level poverty was not. For BMI, all 3 state-level variables were significant predictors of having an above-normal BMI. Evidence was found of the moderating influence of stage of adolescence for both outcomes.
  
  
  CONCLUSIONS
  These findings point to the need for the inclusion of contextual-level data in surveillance systems assessing risk behavior in adolescents and consideration of the multilevel nature of the growing problem of inactivity and above-normal weight when focusing public health prevention efforts.
authors.affiliation: Department of Epidemiology, Mailman School of Public Health, Columbia University, 722 W 168th St, Seventh Floor 720-f, New York, NY 10032, USA. cm2542@columbia.edu
authors.forename: Caroline Mae
authors.initials: CM
authors.lastname: McKay
authors.forename: Bethany A
authors.initials: BA
authors.lastname: Bell-Ellison
authors.forename: Kirsten
authors.initials: K
authors.lastname: Wallace
authors.forename: John M
authors.initials: JM
authors.lastname: Ferron
mesh_terms: D000293:Adolescent; D041923:Adolescent Development; D015992:Body Mass Index; D002648:Child; D005260:Female; D006306:Health Surveys; D006801:Humans; D008019:Life Style; D016014:Linear Models; D008297:Male; D009043:Motor Activity; D015999:Multivariate Analysis; D016017:Odds Ratio; D012931:Social Environment; D012959:Socioeconomic Factors; D014481:United States / Q000453:epidemiology