Dual Trajectories of Sleep Duration and Cigarette Smoking during Adolescence: Relation to Subsequent Internalizing Problems.

Decreasing sleep duration and increasing cigarette smoking of adolescents are major public health concerns. However, research examining connections between the developmental trajectories of the outcomes that are evolving contemporaneously and their relation to long-term outcomes is still lacking. This study examined distinct trajectories of sleep duration and cigarette smoking during adolescence, associations between these trajectories, and links with internalizing problems during young adulthood. Data were collected from 2510 adolescents who participated in a longitudinal study spanning from 2006 through 2014 in northern Taiwan. Group-based dual trajectory modeling was used to examine the dynamic relationships between sleep duration and cigarette smoking trajectories during adolescence. Multiple linear regression was used to understand the association between the distinct trajectories and subsequent internalizing problems. Three sleep duration trajectories (short decreasing, typical sleep, and long sleep) and three cigarette smoking trajectories (nonsmokers, late increasing, and escalating smokers) were identified. We found significant inter-relationships for sleep duration and cigarette smoking trajectories during adolescence; all atypical sleep duration trajectories conferred increased risks of increased cigarette smoking and vice versa. In addition, the effects of sleep duration and cigarette smoking on later internalizing problems were found to vary by sex and trajectory patterns. These results provide insight regarding the co-development of sleep duration and cigarette smoking trajectories during adolescence. We also highlight the different roles of sleep duration and cigarette smoking trajectories and their relation to internalizing problems of young adulthood.