Choi, Tsz Chun Kelvin2010-11-022010-11-022010-08https://hdl.handle.net/11299/96035University of Minnesota Ph.D. dissertation. August 2010.Major: Epidemiology. Advisor: Jean Forster, Ph.D., M.P.H. 1 computer file (PDF); ix, 140 pages, appendices I-II. Ill. (Maps)Smoking in movies has been repeatedly shown to be associated with adolescent smoking. However, previous reports on the association were limited to exposure to top-grossing contemporary movies, and did not assess changes in the exposure over time. These reports were also restricted to exposure during early adolescence (ages 9-15), and focused mainly on initiation of smoking. While they have hypothesized mediators that could potentially explained the association, they did not use a longitudinal study design to assess the abilities of these mediators to explain the association. Using data from the Minnesota Adolescent Community Cohort (n=4735), a prospective observational cohort study with six age cohorts (age cohort 11, 12, 13, 14, 15, and 16), we examined changes in the prevalence of smoking in movies as perceived by teenagers over time. We observed a decline in the perceived prevalence of smoking in movies in all age cohorts, and the decline was steeper in the three older age cohorts than the three younger age cohorts (p<0.05). However, teenagers were still estimated to be exposed to these depictions some of the time at the end of the observation period. We also assessed the effect of changes in the perceived prevalence of smoking in movies on progression of smoking intensity from age 12.5 to 17.9, and found that the perceived prevalence of smoking in movies consistently predicted smoking intensity measured six months later (p<0.05), but only during younger adolescence (exposure from age 13-15.4). In the longitudinal mediation analysis, with data collected when the participants were ages 12-15.9 (n=3112), we found that the perceived prevalence of adult smoking explained an insignificant portion of the association, while the positive expectancies of smoking did not satisfy the criteria for a mediator. Although the amount of smoking in movies has declined, teenagers were still exposed to a moderate amount of these images, which could intensify their smoking behavior, particular when exposed as young adolescents. Further studies are needed to examine other potential mediators to guide the development of interventions to alleviate the negative influence of these images on teenagers.en-USAdolescentLongitudinal trendMoviesSmokingTeenagersEpidemiologyThesis or Dissertation