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.
Four-year longitudinal cohort study (7th-10th grade).
Adolescents completed the questionnaires during school hours.
At total of 741 adolescents with no history of smoking in grade 7 participating in the Montreal Adolescent Depression Development Project.
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.
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.
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.
To identify early predictors of suicidal ideation in young adults, and to determine when specific time-varying determinants become important in predicting later suicidal ideation.
Data were available for 877 participants in the Nicotine Dependence in Teens study, an ongoing prospective cohort of students aged 12 to 13 years at cohort inception in 1999. Time-invariant covariates included age, sex, mother's education, language, and self-esteem. Time-varying covariates included depression symptoms, family stress, other stress, alcohol use, cigarette use, and team sports. Independent predictors of past-year suicidal ideation at age 20 years were identified in 5 multivariable logistic regression analyses, one for each of grades 7, 8, 9, 10, and 11.
Eight per cent of participants (mean age 20.4 years [SD 0.7]; 46% male) reported suicidal ideation in the past year. In grade 7, none of the potential predictor variables were statistically significantly associated with suicidal ideation. In grade 8, participation in sports teams in and (or) outside of school protected against suicidal ideation (OR 0.6; 95% CI 0.4 to 0.8; P = 0.002). Depression symptoms in grades 9, 10, and 11 were independent predictors of suicidal ideation (OR 2.2; 95% CI 1.5 to 3.2, OR 1.6; 95% CI 1.0 to 2.5, and OR 1.9; 95% CI 1.1 to 3.4, respectively). No other variables were statistically significant in the multivariate models.
Depression symptoms as early as in grade 9 predict suicidal ideation in early adulthood. It is possible that early detection and treatment of depression symptoms are warranted as part of suicide prevention programs.