title: The influence of parents, siblings and peers on pre- and early-teen smoking: a multilevel model.
abstract: OBJECTIVE
  Despite considerable success in tobacco control, many teenagers in Australia and other industrialised countries still smoke tobacco. There is mixed evidence on the relative influence of proximal social networks (parents/siblings/peers) on pre- and early-teen smoking, and no research has examined how these influences compare after accounting for school- and community-level effects.The aim of this study was to compare the relative influences of parents, siblings and peers, after accounting for school- and community-level variation in smoking.
  
  
  METHODS
  A cross-sectional fixed and random effects model of smoking prevalence was used, with individuals (n = 7314) nested within schools (n = 231) nested within communities (n = 30). Grade 6 and 8 students (modal ages 11 and 13 years) completed an on-line survey. Key variables included parent/sibling/peer use. Controls included alcohol involvement, sensation seeking, pro-social beliefs, laws/norms about substance use and school commitment.
  
  
  RESULTS
  There was significant variation in smoking at both the school and community levels, supporting the need for a multilevel model. Individual-level predictors accounted for much of the variance at higher levels. The strongest effects were for number of friends who smoke, sibling smoking and alcohol involvement. Smaller significant effects were found for parent smoking. At the community level, socioeconomic disadvantage was significant, but community-level variance in pro-social and drug-related laws/norms was not related to smoking.
  
  
  CONCLUSIONS
  Cross-level interactions were generally non-significant. Early teenage smoking was best explained by sibling and peer smoking, and individual risks largely accounted for the substantial variation observed across schools and communities. In terms of future tobacco control, findings point to the utility of targeting families in disadvantaged communities.
authors.affiliation: Centre for Youth Substance Abuse Research, The University of Queensland, Brisbane, Australia. a.kelly@uq.edu.au
authors.forename: Adrian B
authors.initials: AB
authors.lastname: Kelly
authors.forename: Martin
authors.initials: M
authors.lastname: O'Flaherty
authors.forename: Jason P
authors.initials: JP
authors.lastname: Connor
authors.forename: Ross
authors.initials: R
authors.lastname: Homel
authors.forename: John W
authors.initials: JW
authors.lastname: Toumbourou
authors.forename: George C
authors.initials: GC
authors.lastname: Patton
authors.forename: Joanne
authors.initials: J
authors.lastname: Williams
mesh_terms: D000293:Adolescent; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007398:Interpersonal Relations; D008297:Male; D008960:Models, Psychological; D010290:Parents / Q000523:psychology*; D010379:Peer Group; D012111:Residence Characteristics; D012307:Risk Factors; D012574:Schools; D035781:Siblings / Q000523:psychology*; D012907:Smoking / Q000453:epidemiology* / Q000523:psychology*; D012944:Social Support; D013334:Students; D014029:Tobacco Use Disorder / Q000453:epidemiology / Q000523:psychology*; D014026:Nicotiana