title: A longitudinal study of exposure to retail cigarette advertising and smoking initiation.
abstract: OBJECTIVE
  Accumulating evidence suggests that widespread advertising for cigarettes at the point of sale encourages adolescents to smoke; however, no longitudinal study of exposure to retail tobacco advertising and smoking behavior has been reported.
  
  
  METHODS
  A school-based survey included 1681 adolescents (aged 11-14 years) who had never smoked. One measure of exposure assessed the frequency of visiting types of stores that contain the most cigarette advertising. A more detailed measure combined data about visiting stores near school with observations of cigarette advertisements and pack displays in those stores. Follow-up surveys 12 and 30 months after baseline (retention rate: 81%) documented the transition from never to ever smoking, even just a puff.
  
  
  RESULTS
  After 12 months, 18% of adolescents initiated smoking, but the incidence was 29% among students who visited convenience, liquor, or small grocery stores at least twice per week and 9% among those who reported the lowest visit frequency (less than twice per month). Adjusting for multiple risk factors, the odds of initiation remained significantly higher (odds ratio: 1.64 [95% confidence interval: 1.06-2.55]) for adolescents who reported moderate visit frequency (0.5-1.9 visits per week), and the odds of initiation more than doubled for those who visited > or = 2 times per week (odds ratio: 2.58 [95% confidence interval: 1.68-3.97]). Similar associations were observed for the more detailed exposure measure and persisted at 30 months.
  
  
  CONCLUSIONS
  Exposure to retail cigarette advertising is a risk factor for smoking initiation. Policies and parenting practices that limit adolescents' exposure to retail cigarette advertising could improve smoking prevention efforts.
authors.affiliation: Stanford University School of Medicine, Stanford Prevention Research Center, Palo Alto, CA 94304-1334, USA. lhenriksen@stanford.edu
authors.forename: Lisa
authors.initials: L
authors.lastname: Henriksen
authors.forename: Nina C
authors.initials: NC
authors.lastname: Schleicher
authors.forename: Ellen C
authors.initials: EC
authors.lastname: Feighery
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Fortmann
mesh_terms: D000293:Adolescent; D000329:Advertising / Q000706:statistics & numerical data*; D003132:Commerce / Q000706:statistics & numerical data* / Q000639:trends*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D012907:Smoking / Q000453:epidemiology*