title: Early exposure to movie smoking predicts established smoking by older teens and young adults.
abstract: OBJECTIVE
  Movie smoking exposure is a strong predictor of smoking initiation by adolescents; however, we do not know whether it is a long-term predictor of established smoking. We conducted a prospective study to determine whether movie smoking exposure during early adolescence predicts established smoking in older teens and young adults.
  
  
  METHODS
  We assessed movie smoking exposure and smoking status through a written school-based survey in 1999, when participants were 10 to 14 years of age. We enrolled 73% (n = 2603) of those who had never tried smoking in a follow-up study. In 2006-2007, we conducted telephone interviews with 69% (n = 1791) of the cohort to ascertain current smoking status. The primary outcome was established smoking, defined as having smoked >100 cigarettes. Mean age at follow-up was 18.7 years.
  
  
  RESULTS
  Thirteen percent (n = 235) progressed from never smoking to established smoking during the follow-up period. Eighty-nine percent (n = 209) of established smokers smoked during the 30 days before the survey. Even after controlling for a wide range of baseline characteristics, the relative risk for established smoking increased by one third with each successive quartile of movie smoking exposure. Those in the highest quartile for baseline movie smoking exposure were twice as likely to be established smokers at follow-up compared with those in the lowest quartile.
  
  
  CONCLUSIONS
  Movie smoking exposure significantly predicted progression to established smoking in long-term follow-up. We estimate that 34.9% of established smoking in this cohort can be attributed to movie smoking exposure.
authors.affiliation: Hood Center for Children and Families, Dartmouth Medical School, HB 7465, One Medical Center Dr, Lebanon, NH 03756, USA. madeline.a.dalton@dartmouth.edu
authors.forename: Madeline A
authors.initials: MA
authors.lastname: Dalton
authors.forename: Michael L
authors.initials: ML
authors.lastname: Beach
authors.forename: Anna M
authors.initials: AM
authors.lastname: Adachi-Mejia
authors.forename: Meghan R
authors.initials: MR
authors.lastname: Longacre
authors.forename: Aurora L
authors.initials: AL
authors.lastname: Matzkin
authors.forename: James D
authors.initials: JD
authors.lastname: Sargent
authors.forename: Todd F
authors.initials: TF
authors.lastname: Heatherton
authors.forename: Linda
authors.initials: L
authors.lastname: Titus-Ernstoff