title: Association of established smoking among adolescents with timing of exposure to smoking depicted in movies.
abstract: BACKGROUND
  It is not known whether exposure to smoking depicted in movies carries greater influence during early or late adolescence. We aimed to quantify the independent relative contribution to established smoking of exposure to smoking depicted in movies during both early and late adolescence.
  
  
  METHODS
  We prospectively assessed 2049 nonsmoking students recruited from 14 randomly selected public schools in New Hampshire and Vermont. At baseline enrollment, students aged 10-14 years completed a written survey to determine personal, family, and sociodemographic characteristics and exposure to depictions of smoking in the movies (early exposure). Seven years later, we conducted follow-up telephone interviews to ascertain follow-up exposure to movie smoking (late exposure) and smoking behavior. We used multiple regression models to assess associations between early and late exposure and development of established smoking.
  
  
  RESULTS
  One-sixth (17.3%) of the sample progressed to established smoking. In analyses that controlled for covariates and included early and late exposure in the same model, we found that students in the highest quartile for early exposure had 73% greater risk of established smoking than those in the lowest quartile for early exposure (27.8% vs 8.6%; relative risk for Q4 vs Q1 = 1.73, 95% confidence interval = 1.14 to 2.62). However, late exposure to depictions of smoking in movies was not statistically significantly associated with established smoking (22.1% vs 14.0%; relative risk for Q4 vs Q1 = 1.13, 95% confidence interval = 0.89 to 1.44). Whereas 31.6% of established smoking was attributable to early exposure, only an additional 5.3% was attributable to late exposure.
  
  
  CONCLUSIONS
  Early exposure to smoking depicted in movies is associated with established smoking among adolescents. Educational and policy-related interventions should focus on minimizing early exposure to smoking depicted in movies.
authors.affiliation: Department of Medicine, University of Pittsburgh School of Medicine, 230 McKee Place, Ste 600, Pittsburgh, PA 15217, USA. bprimack@pitt.edu
authors.forename: Brian A
authors.initials: BA
authors.lastname: Primack
authors.forename: Meghan R
authors.initials: MR
authors.lastname: Longacre
authors.forename: Michael L
authors.initials: ML
authors.lastname: Beach
authors.forename: Anna M
authors.initials: AM
authors.lastname: Adachi-Mejia
authors.forename: Linda J
authors.initials: LJ
authors.lastname: Titus
authors.forename: Madeline A
authors.initials: MA
authors.lastname: Dalton
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior / Q000523:psychology; D000367:Age Factors; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007100:Imitative Behavior; D008137:Longitudinal Studies; D008297:Male; D009040:Motion Pictures; D015999:Multivariate Analysis; D009513:New Hampshire / Q000453:epidemiology; D016012:Poisson Distribution; D012574:Schools; D012907:Smoking / Q000453:epidemiology* / Q000523:psychology; D011795:Surveys and Questionnaires; D013997:Time Factors; D014707:Vermont / Q000453:epidemiology; D055815:Young Adult