Cohort effects associated with reduced sleep duration in adolescents

The purpose of this study is to examine how the sleep duration changes during adolescence across the seventh, eighth, ninth, and 10th grade periods, and to determine whether there is a difference between the cohorts.

For these purposes, we used the latent growth curve modeling and the multi-group analysis involving 2081 students (2000-birth cohort data) and 2254 students (1997-birth cohort data) who participated in the Korean Children and Youth Panel Survey. The data were collected using a stratified multistage cluster sampling method.

Sleep duration became shorter as age increased. Furthermore, the sleep duration of the 2000-birth cohort became shorter than the sleep duration of the 1997-birth cohort. Specifically, the mean value of the initial sleep duration of the 2000-birth cohort was 8.09 h, which was significantly shorter than the initial value 8.36 h of the sleep duration of the 1997-birth cohort. In addition, multi-group analysis revealed that the trajectories of sleep duration and its predictors were varied by cohort. Specifically, parent supervision, peer relationship, and electronic media factors (smartphone overuse, time spent on using computer and playing games) explained the cohort effect.

These findings suggest that environmental factors such as increasing use of electronic media or pressure regarding higher education to adolescents could be associated with reduced sleep duration.