Secular trends in adolescent never smoking from 1990 to 1999 in California: An age-period-cohort analysis

Objectives. 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 = 26536; 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.