title: The Influence of the National truth campaign on smoking initiation.
abstract: BACKGROUND
  States and national organizations spend millions annually on antismoking campaigns aimed at youth. Much of the evidence for their effectiveness is based on cross-sectional studies. This study was designed to evaluate the effectiveness of a prominent national youth smoking-prevention campaign in the U.S. known as truth that was launched in February 2000.
  
  
  METHODS
  A nationally representative cohort of 8904 adolescents aged 12-17 years who were interviewed annually from 1997 to 2004 was analyzed in 2008. A quasi-experimental design was used to relate changes in smoking initiation to variable levels of exposure to antismoking messages over time and across 210 media markets in the U.S. A discrete-time hazard model was used to quantify the influence of media market delivery of TV commercials on smoking initiation, controlling for confounding influences. Based on the results of the hazard model, the number of youth nationally who were prevented from smoking from 2000 through 2004 was estimated.
  
  
  RESULTS
  Exposure to the truth campaign is associated with a decreased risk of smoking initiation (relative risk=0.80, p=0.001). Through 2004, approximately 450,000 adolescents were prevented from trying smoking nationwide. Factors negatively associated with initiation include African-American race (relative risk=0.44, p<0.001), Hispanic ethnicity (relative risk=0.74, p<0.001), completing high school (relative risk=0.69, p<0.001), and living with both parents at baseline (OR=0.79, p<0.001).
  
  
  CONCLUSIONS
  The current study strengthens the available evidence for antismoking campaigns as a viable strategy for preventing youth smoking.
authors.affiliation: RTI International, Research Triangle Park, North Carolina 27709, USA. mcf@rti.org
authors.forename: Matthew C
authors.initials: MC
authors.lastname: Farrelly
authors.forename: James
authors.initials: J
authors.lastname: Nonnemaker
authors.forename: Kevin C
authors.initials: KC
authors.lastname: Davis
authors.forename: Altijani
authors.initials: A
authors.lastname: Hussin
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior; D002648:Child; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008402:Mass Media; D000074606:Smoking Prevention; D040241:Social Marketing; D014481:United States