title: Secular trends in adolescent never smoking from 1990 to 1999 in California: an age-period-cohort analysis.
abstract: OBJECTIVE
  We analyzed age, time period, and cohort effects on trends in adolescent cigarette smoking in California from 1990 to 1999.
  
  
  METHODS
  Data from subjects aged 12 to 17 years (n = 26 536; 50.4% male) from the California Tobacco Survey and the California Youth Tobacco Survey were analyzed, and never smokers were used as the outcome measure.
  
  
  RESULTS
  The proportion of never smokers increased from 60% for males and 66% for females in 1990 to around 70% for both sexes in 1999. Respondents were more likely to be never smokers if born in 1978 or later (i.e., aged 12 years or younger in 1990, when most tobacco control programs started in California).
  
  
  CONCLUSIONS
  The statewide antitobacco programs prevented adolescents from starting to smoke, primarily through a cohort effect.
authors.affiliation: University of Southern California Keck School of Medicine, Los Angeles, USA. jimchen@med.wayne.edu
authors.forename: Xinguang
authors.initials: X
authors.lastname: Chen
authors.forename: Guohua
authors.initials: G
authors.lastname: Li
authors.forename: Jennifer B
authors.initials: JB
authors.lastname: Unger
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Liu
authors.forename: C Anderson
authors.initials: CA
authors.lastname: Johnson
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior; D017677:Age Distribution; D017668:Age of Onset; D002140:California / Q000453:epidemiology; D002648:Child; D015331:Cohort Studies; D005260:Female; D006293:Health Promotion; D006801:Humans; D008297:Male; D015233:Models, Statistical; D017063:Outcome Assessment, Health Care; D015995:Prevalence; D015397:Program Evaluation; D012907:Smoking / Q000453:epidemiology* / Q000331:legislation & jurisprudence; D000074606:Smoking Prevention; D011049:Social Control Policies / Q000331:legislation & jurisprudence*