title: Longitudinal variation in adolescent physical activity patterns and the emergence of tobacco use.
abstract: OBJECTIVE
  The objective of this investigation was to examine how variation in adolescent physical activity is related to smoking and alternative tobacco use.
  
  
  METHODS
  Adolescents (N = 1,384) completed a self-report survey every 6 months from ages 14- to 18-years old in a prospective study of health behaviors. The 8 waves of data were analyzed using General Growth Mixture Modeling (GGMM)  RESULTS: GGMM identified five physical activity trajectories including stable higher (SHPA), decreased (DPA), stable regular (SRPA), curvilinear (CPA), and stable low (SLPA). Across 4 years, the likelihood of smoking was greater among adolescents in the DPA, SLPA and SRPA trajectories compared to adolescents belonging to the SHPA trajectory. Alternative tobacco use was greatest among adolescents in the DPA and SRPA trajectories.
  
  
  CONCLUSIONS
  Adolescents with decreasing physical activity and even adolescents averaging an hour of physical activity a day (SRPA) are important groups to target for tobacco use prevention and intervention efforts.
authors.affiliation: Department of Psychiatry, University of Pennsylvania, Philadelphia, PA, USA. audrain@mail.med.upenn.edu
authors.forename: Janet
authors.initials: J
authors.lastname: Audrain-McGovern
authors.forename: Daniel
authors.initials: D
authors.lastname: Rodriguez
authors.forename: Kelli
authors.initials: K
authors.lastname: Rodgers
authors.forename: Jocelyn
authors.initials: J
authors.lastname: Cuevas
authors.forename: Joseph
authors.initials: J
authors.lastname: Sass
mesh_terms: D000293:Adolescent; D041923:Adolescent Development / Q000502:physiology*; D005260:Female; D006306:Health Surveys; D006801:Humans; D008297:Male; D008960:Models, Psychological; D009043:Motor Activity / Q000502:physiology*; D011446:Prospective Studies; D011795:Surveys and Questionnaires; D014029:Tobacco Use Disorder / Q000453:epidemiology*