Transition through smoking stages in adolescents: an innovative perspective using growth mixture models

Aim: Little has been studied about the transition from initial smoking experimentation to future regular smoking in adolescents. We therefore aimed to describe the stages of the transition to smoking process in adolescents using growth mixture models (GMMs). Subject and methods: In this two-phase cohort study, a representative sample of 4903 10th-grade students was assessed using multistage sampling in Tabriz, Iran. The main outcomes comprising smoking status, intention to start smoking, and smoking during the past week/month, were collected in addition to the predictors, using valid and reliable instruments. The optimal number of classes was determined, and GMMs were conducted with covariates. Results: Decisively, GMMs emerged as a three-class optimal model comprising “Smokers and intending smokers” (5.5%), “Occasional smokers” (17.7%), and “Non-smokers” (76.8%). GMMs lead in significant intercepts (range over 1.3 to 37.8) and significant and positive slopes (range over 0.32 to 1.44) for the change in outcomes (all p < 0.05). Higher age, being male, higher socio-economic status, having a smoker friend, having a smoker in the family, substance abuse, and self-injury, higher attitude toward smoking, and general risk-taking behavior were directly related to a positive change in outcomes (all p < 0.05). Conclusions: The GMMs, highlighted two substantial initiations and transitions through smoking stages in adolescents with effective and directed programs, and second, the importance of implementing educational campaigns, public-awareness initiatives, and targeted interventions in the future.