title: Shared norms and their explanation for the social clustering of obesity.
abstract: OBJECTIVE
  We aimed to test the hypothesized role of shared body size norms in the social contagion of body size and obesity.
  
  
  METHODS
  Using data collected in 2009 from 101 women and 812 of their social ties in Phoenix, Arizona, we assessed the indirect effect of social norms on shared body mass index (BMI) measured in 3 different ways.
  
  
  RESULTS
  We confirmed Christakis and Fowler's basic finding that BMI and obesity do indeed cluster socially, but we found that body size norms accounted for only a small portion of this effect (at most 20%) and only via 1 of the 3 pathways.
  
  
  CONCLUSIONS
  If shared social norms play only a minor role in the social contagion of obesity, interventions targeted at changing ideas about appropriate BMIs or body sizes may be less useful than those working more directly with behaviors, for example, by changing eating habits or transforming opportunities for and constraints on dietary intake.
authors.affiliation: School of Human Evolution and Social Change, Arizona State University,Tempe, AZ 85287-2402, USA. dhruschk@asu.edu
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Hruschka
authors.forename: Alexandra A
authors.initials: AA
authors.lastname: Brewis
authors.forename: Amber
authors.initials: A
authors.lastname: Wutich
authors.forename: Benjamin
authors.initials: B
authors.lastname: Morin
mesh_terms: D000293:Adolescent; D000328:Adult; D001130:Arizona / Q000453:epidemiology; D015992:Body Mass Index; D016000:Cluster Analysis; D005190:Family; D005260:Female; D006801:Humans; D007398:Interpersonal Relations; D007407:Interviews as Topic; D008875:Middle Aged; D009765:Obesity / Q000453:epidemiology / Q000523:psychology*; D012919:Social Behavior; D055815:Young Adult