Objective: To identify which key transitions in the adolescent smoking uptake process changed during periods of increasing and decreasing adolescent smoking participation in California.
Methods: Age groups (12-14 and 15-17 years) from longitudinal surveys of California adolescents, conducted in 1993-1996 (prevalence increasing) and in 1996-1999 (prevalence declining), allowed comparisons of transition rates across these periods for: never smokers (committed and susceptible) to any smoking, experimenters to established smokers, and current established smokers to former smokers (15-17-year-olds only). Analyses adjusted for demographics and other baseline environmental influences on adolescents to smoke, with a variable for 'time period' included to test for differential period transition rates.
Results: Adjusted analyses indicated a time period effect (1993-1996 versus 1996-1999) on all transitions examined for 12-14-year-olds. For 15-17-year-olds, the time period effect was significant for the transition from committed never smoker to any smoking, but only marginally significant for experimenter to established smoker and from current established to former smoker.
Conclusion: Adolescent smoking participation appeared to decline at all phases in the smoking uptake process, with generally larger declines in younger adolescents. Intensified public health measures to curb adolescent smoking beginning in the mid 1990s may have been responsible.