Academic achievement and smoking initiation in adolescence : a general growth mixture analysis

Aims This study aims to: (i) explore the relations between smoking initiation and different profiles of academic achievement trajectories in early to mid-adolescence; and (ii) to investigate whether background characteristics (gender, ethnicity, grade repetition, parental education) and proximal processes (parental practices, extra-curricular involvement) predicted class membership and smoking initiation. Design Four-year longitudinal cohort study (7th-10th grade). Setting Adolescents completed the questionnaires during school hours. Participants At total of 741 adolescents with no history of smoking in grade 7 participating in the Montreal Adolescent Depression Development Project. Measurements Self-report questionnaires were used to assess predictors and previous smoking in year 1, and smoking initiation by the end of the study. Grade point average (GPA) was obtained twice yearly from school records. Findings Three academic achievement trajectories were identified and found to differ significantly in rates of smoking initiation: persistently high achievers (7.1% smoking), average achievers (15.1% smokers) and unstable low achievers (49.1% smoking). Further, results showed that general parenting practices and parental education indirectly reduced the likelihood of smoking by reducing the risk of membership in classes with lower GPA. Conclusions Adolescents who do well in school are less likely to smoke and it may be cost-effective for smoking prevention to focus on the few (12%) easy to identify unstable low achievers who form 35% of smoking onsets. In addition, as parental support and democratic control reduced the likelihood of poor academic performance, promoting essential generic parenting skills from a young age may also prevent future onsets of smoking in adolescence.