title: Exposure to parental and sibling smoking and the risk of smoking uptake in childhood and adolescence: a systematic review and meta-analysis.
abstract: BACKGROUND
  There is increasing evidence that contact with other smokers, particularly in the family, is a strong determinant of risk of smoking uptake. A systematic review and meta-analysis of the magnitude of these effects is reported.
  
  
  METHODS
  Studies were identified by searching four databases to March 2009 and proceedings from international conferences. Meta-analyses were performed using random effects, with results presented as pooled ORs with 95% CIs.
  
  
  RESULTS
  58 studies were included in the meta-analyses. The relative odds of uptake of smoking in children were increased significantly if at least one parent smoked (OR 1.72, 95% CI 1.59 to 1.86), more so by smoking by the mother (OR 2.19, 95% CI 1.73 to 2.79) than the father (OR 1.66, 95% CI 1.42 to 1.94), and if both parents smoked (OR 2.73, 95% CI 2.28 to 3.28). Smoking by a sibling increased the odds of smoking uptake by 2.30 (95% CI 1.85 to 2.86) and smoking by any household member by 1.92 (95% CI 1.70 to 2.16). After adjusting for overestimation of RRs it is estimated that, in England and Wales, around 17,000 young people take up smoking by the age of 15 each year as a consequence of exposure to household smoking.
  
  
  CONCLUSIONS
  Parental and sibling smoking is a strong and significant determinant of the risk of smoking uptake by children and young people and, as such, is a major and entirely avoidable health risk. Children should be protected from exposure to smoking behaviour, especially by family members.
authors.affiliation: UK Centre for Tobacco Control Studies, Division of Epidemiology and Public Health,University of Nottingham, UK. jo.leonardi-bee@nottingham.ac.uk
authors.forename: Jo
authors.initials: J
authors.lastname: Leonardi-Bee
authors.forename: Mirriam Lisa
authors.initials: ML
authors.lastname: Jere
authors.forename: John
authors.initials: J
authors.lastname: Britton
mesh_terms: D000293:Adolescent; D002648:Child; D005260:Female; D006801:Humans; D007100:Imitative Behavior; D015994:Incidence; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000453:epidemiology*; D015995:Prevalence; D018570:Risk Assessment; D012307:Risk Factors; D035781:Siblings; D012907:Smoking / Q000009:adverse effects* / Q000453:epidemiology; D014028:Tobacco Smoke Pollution / Q000009:adverse effects*; D006113:United Kingdom / Q000453:epidemiology
chemical_list: D014028:Tobacco Smoke Pollution