Predictors of Transition in Different Stages of Smoking: A Longitudinal Study

BACKGROUND: We investigated longitudinally the prevalence of smoking according to three stages of smoking (never smoking, experimenting the smoking, and regular smoking), the rates of transition from one stage to another one, and determinant predictors of transition through these stages of smoking. METHODS: Of all 10(th) grade students in Tabriz, 1785 students were randomly selected and assessed twice, with a 12-month interval, with respect to the changes of stage. The predictor variables were measured when the students were in the 10(th) grade. Logistic regression and principal component analysis were used to analysis data at grade 11. FINDINGS: Of 1785 students, 14.3% (CI 95%: 12.3-16.4) and 2.8% (CI 95%: 2.0-4.0) of the never smokers became experimenters and regular smokers, respectively and 16.5% (CI 95%: 12.4-21.7) of the experimenters became regular smokers. Among never smokers, participating in smoker groups (OR=1.24), having smoker friends (OR=1.85) and a positive attitude towards smoking (OR=1.22) predicted experimentation; and participating in smokers groups (OR=1.35) and a lower socioeconomic class (OR=0.36) predicted regular smoking. Among experimenters, students having general high risk behaviors (OR=2.56) and participating in smoker groups (OR=2.58) were distinguished as those who progressed to regular smoking in follow-up. CONCLUSION: Programs aimed at smoking prevention and intervention should incorporate plans which focus on predictors of transition through smoking stages, and targeting participation in smoker groups.