title: Geographical clustering of eating disordered behaviors in U.S. high school students.
abstract: OBJECTIVE
  The aim of this study was to determine if eating disorder behaviors geographically clustered among U.S high school students.
  
  
  METHODS
  Our sample consisted of 15,349 high school students who responded to the 1999 Youth Risk Behavior Study (YRBS). Weight control and eating disordered behaviors under investigation included dieting, exercising, fasting, using diet pills, and purging to control weight in the last 30 days. We calculated pairwise odds ratios (PWORs) to determine the degree of within-county clustering.
  
  
  RESULTS
  Among all participants, adjusted analyses revealed that having any weight control or eating disorder symptom, severe restricting, dieting, exercising, and diet pill use each showed significant clustering (p < .05). Purging did not significantly cluster by county. The magnitude of clustering was stronger for female students than male students.
  
  
  CONCLUSIONS
  The significant clustering of weight control and eating disorder behavior in U.S. high school students confirms evidence of a social contagion effect of eating disorders.
authors.affiliation: Center for Research on Implementation of Innovative Strategies in Practice, VA Iowa City Health Care System, Iowa City, Iowa, USA. valerie-hoffman@uiowa.edu
authors.forename: Valerie L
authors.initials: VL
authors.lastname: Forman-Hoffman
authors.forename: Cassie L
authors.initials: CL
authors.lastname: Cunningham
mesh_terms: D000293:Adolescent; D015992:Body Mass Index; D002391:Catchment Area, Health; D005006:Ethnicity / Q000706:statistics & numerical data; D005215:Fasting; D005247:Feeding Behavior; D001068:Feeding and Eating Disorders / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology*; D005260:Female; D005843:Geography; D006801:Humans; D015994:Incidence; D008297:Male; D015995:Prevalence; D012309:Risk-Taking; D012574:Schools; D017678:Sex Distribution; D013334:Students / Q000523:psychology* / Q000706:statistics & numerical data*; D011795:Surveys and Questionnaires; D014481:United States / Q000453:epidemiology