Early Predictors of Trajectories of Tobacco Use Level from Adolescence to Young Adulthood: A 16-Year Follow-Up of the TEMPO Cohort Study (1999-2015).

Purpose: Individual and family characteristics early on in life are associated with adolescent smoking; however, their role with regard to long-term tobacco smoking trajectories into young adulthood is not well-known, which is what we set out to study using data from a longitudinal community-based cohort.

Methods: We used data from 2,025 youths in France (12-26 years at baseline, 16 years of follow-up), participating in the longitudinal TEMPO cohort study. First, we modeled smoking trajectories from adolescence onwards using Group-Based Trajectory Modeling, by using the declared consumption of cigarettes at different ages. Second, among trajectories of smokers, associations with individual and family characteristics in childhood and adolescence were studied using multinomial logistic regression.

Results: We observed 5 smoking trajectories: non-smokers (62.3%), 3 groups of persistent smokers with different levels of tobacco use (low, intermediate, high), and a group characterized by high-level smoking followed by cessation. Among participants who were lifetime smokers (n = 763), the trajectory of tobacco use was associated with early substance use initiation, academic attainment, grade retention, and parental smoking. Early tobacco and cannabis use initiation predicted high-level tobacco use, whether it persisted (OR 2.29, 95% CI 1.23-4.28) or not (OR 2.99, 95% CI 1.59-5.63). Grade retention and parental smoking predicted persistent smoking of intermediate (respectively OR 1.53, 95% CI 1.03-1.92; OR 1.74, 95% CI 1.03-2.92) or high level use (respectively OR 1.74, 95% CI 1.07-2.85; OR 1.70, 95% CI 0.91-3.18). Poor academic attainment predicted all 3 smoking trajectories, especially persistent high-level smoking (no high school degree: OR 5.29, 95% CI 1.65-16.97, vocational degree: OR 1.94, 95% CI 0.99-3.80).

Conclusions: Tobacco smoking trajectories from adolescence to adulthood are associated with early substance use initiation, parental smoking, and academic difficulties.