title: Disentangling social selection and social influence effects on adolescent smoking: the importance of reciprocity in friendships.
abstract: OBJECTIVE
  The goal of this study was to examine social selection and social influence within reciprocal and non-reciprocal friendships, and the role of parents and siblings, as factors explaining similarity of smoking behaviour among adolescent friends. A new social selection-social influence model is proposed.
  
  
  METHODS
  Longitudinal design with two measurements.
  
  
  METHODS
  Data were gathered among Dutch high school students in the control group of the European Smoking prevention Framework Approach (ESFA) study.
  
  
  METHODS
  The sample consisted of 1886 adolescents with a mean age of 12.7 years.
  
  
  METHODS
  The main outcome measures were the smoking behaviours of the respondents, best friends, parents and siblings. We tested the social selection-social influence model with structural equation modelling techniques.
  
  
  RESULTS
  Social selection and social influence both played an important role in explaining similarity of smoking behaviour among friends. Within non-reciprocal friendships, only social selection explained similarity of smoking behaviour, whereas within reciprocal friendships, social influence and possibly also social selection explained similarity of smoking behaviour. Sibling smoking behaviour was a more important predictor of adolescent smoking behaviour than parental smoking behaviour.
  
  
  CONCLUSIONS
  Social selection and social influence both promote similarity of smoking behaviour, and the impact of each process differs with the degree of reciprocity of friendships. These insights may contribute to further refinement of smoking prevention strategies.
authors.affiliation: Care and Public Heath research Institute, University of Maastricht, Maastricht, The Netherlands. liesbeth.mercken@gvo.unimaas.nl
authors.forename: Liesbeth
authors.initials: L
authors.lastname: Mercken
authors.forename: Math
authors.initials: M
authors.lastname: Candel
authors.forename: Paul
authors.initials: P
authors.lastname: Willems
authors.forename: Hein
authors.initials: H
authors.lastname: de Vries
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior / Q000523:psychology*; D001294:Attitude to Health; D005260:Female; D006801:Humans; D007398:Interpersonal Relations; D008137:Longitudinal Studies; D008297:Male; D009426:Netherlands / Q000453:epidemiology; D010287:Parent-Child Relations; D010379:Peer Group; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects* / Q000453:epidemiology; D000074606:Smoking Prevention