Instability in smoking patterns among school leavers in Victoria, Australia

To describe patterns of smoking in a cohort of young adults over the first 15 months after leaving school.

A four-wave, longitudinal survey design was used to gather data. Final-year students from 93 schools completed the recruitment questionnaire at an average age of 17 years. Follow-up questionnaires were posted to their home addresses three months, nine months and 15 months after the end of school.

Victoria, Australia.

A cohort of 1903 respondents who completed and returned all four questionnaires.

Self-labelled smoking status ("heavy smoker", "light smoker", "occasional smoker", "ex-smoker", and "non-smoker"), daily cigarette consumption, and maximum daily cigarette consumption.

At school, 72% of the sample were "non-smokers", 5% "ex-smokers", 11% "occasional", 8% "light", and 5% "heavy smokers". At 15 months after school, these proportions had shifted to 64%, 8%, 11%, 9%, and 7%, respectively. Over the study, "light smokers" and "heavy smokers" substantially increased their daily consumption; "occasional" and "ex-smokers" did not. There was relatively high stability in self-labelled smoking status at one wave and the next. However, over the four waves, 38% of the sample changed their self-labelled smoking status, and 41% of these had been "non-smokers" at school. A reduced second-order Markov chain model was found to fit this four-wave behavioural sequence. Detailed description of smoking status changes revealed greater progression to higher levels of smoking than transition to lower levels.

There is considerable flux in smoking patterns among young adults after leaving school, suggesting an opportunity to intervene with smoking prevention programmes at this stage of development.