Changes in age trajectories of smoking experimentation during the California Tobacco Control Program.

OBJECTIVES: We aimed to investigate population-level changes in smoking initiation during California's Tobacco Control (CTC) Program from 1990 to 2005, a period during which tobacco industry marketing practices also changed.
METHODS: We used a discrete time survival analysis of data from the California Tobacco Survey to model changes in age of first smoking experimentation across birth cohorts.
RESULTS: Smoking initiation patterns were stable across cohorts aged 9 years or older at the start of the CTC program. For children entering preadolescence since 1990, initiation declined with each more recent cohort. By 2005, the observed decline in experimentation was 80% for male participants and 92% for female participants at age 12 to 14 years; by age 15 to 17 years, 10% of Californian adolescents had experimented in 2005 compared with 45% in preprogram cohorts. However, rates of new experimentation after age 17 years did not change, except for a recent increase in late experimentation (after age 20 years) among young adult men.
CONCLUSION: Our models suggest that the CTC program greatly reduced adolescent smoking initiation among younger adolescents. Late experimentation may have recently increased among young adult men in California, coincident with an increase in tobacco industry marketing aimed at young adults.