title: Peer associations for substance use and exercise in a college student social network.
abstract: Substance use and exercise have opposite trajectories in young adulthood, and research indicates that peers are influential for both of these health behaviors, but simultaneous investigations of peer associations with substance use and exercise have not been conducted.
  
  
  OBJECTIVE
  Use a college residence hall peer network to examine associations between peer behaviors and alcohol use, marijuana use, and exercise behavior.
  
  
  METHODS
  129 undergraduates (51.9% female, 48.1% non-Hispanic White; 84.5% first-year students) in one residence hall completed a Web-based survey of substance use and exercise and identified up to 10 students in the residence hall who were important to them. Two social network analytic methods, community detection cluster analysis and network autocorrelation modeling, were used to identify peer groupings and to examine the associations between peer and participant behaviors, respectively.
  
  
  RESULTS
  Participants nominated an average of 4.1 residence hall members, and 53.9% of the ties were reciprocal. 6 clusters were identified that differed significantly on demographics, college activities, substance use, and exercise. Weekly volume of alcohol consumed among nominated peers was significantly associated with that of participants, and all other covariates, including gender and athlete status, were not significant. Peer marijuana use also was associated with participant use after controlling for covariates. Exercise levels of nominated peers were not associated with exercise levels of participants.
  
  
  CONCLUSIONS
  College student networks may be good targets for health-related prevention programs. Programs that use close-proximity peers to influence the behavior of others might be more effective with substance use as the target behavior than exercise.
authors.affiliation: Center for Alcohol and Addiction Studies.
authors.forename: Nancy P
authors.initials: NP
authors.lastname: Barnett
authors.affiliation: Department of Biostatistics, Brown University.
authors.forename: Miles Q
authors.initials: MQ
authors.lastname: Ott
authors.affiliation: Center for Population Health and Clinical Epidemiology, Brown University.
authors.forename: Michelle L
authors.initials: ML
authors.lastname: Rogers
authors.affiliation: Center for Alcohol and Addiction Studies.
authors.forename: Michelle
authors.initials: M
authors.lastname: Loxley
authors.affiliation: Department of Biostatistics, Brown University.
authors.forename: Crystal
authors.initials: C
authors.lastname: Linkletter
authors.affiliation: Center for Population Health and Clinical Epidemiology.
authors.forename: Melissa A
authors.initials: MA
authors.lastname: Clark
mesh_terms: D000293:Adolescent; D000428:Alcohol Drinking / Q000453:epidemiology*; D016000:Cluster Analysis; D003625:Data Collection; D015444:Exercise; D005260:Female; D006801:Humans; D020407:Internet; D007398:Interpersonal Relations; D008297:Male; D002189:Marijuana Abuse / Q000453:epidemiology*; D010379:Peer Group; D012944:Social Support; D012963:Sociometric Techniques; D013334:Students / Q000706:statistics & numerical data*; D014495:Universities; D055815:Young Adult