Late night screen usage and screentime addiction as shared determinants of insomnia, obesity and wellbeing in 11–14-year-olds.

Introduction
In Europe, 20% of adolescents are classified as overweight or obese, and 69% of adolescents do not meet recommended sleep guidelines; 49% have poor sleep quality. Among teenagers’ poor sleep and adiposity have been found to be associated. The aim of this study was to identify modifiable shared determinants of poor sleep and increased adiposity.
Methods
A cross-sectional study of 11–14-year-olds was conducted (Figure 1). Objective sleep timing variables were measured using actigraphy (ActiGraph-GT3X) over seven nights. Sleep quality, sleep habits and insomnia symptoms were also assessed. Body mass index percentile (pBMI) was used as an index of obesity. Validated self-assessed questionnaires were used to assess screentime addiction (videogaming, social media, mobile phone), wellbeing and chronotype. Hierarchical regression analysis was conducted, and models were adjusted for age, gender, ethnicity, socioeconomic status, and puberty.
Results
Sixty-two adolescents (29M/33F, 12.2±1.13yrs, pBMI 60.3±32.0) completed the study. Significant bivariate correlations were identified between screentime timing (late night and early morning phone use) and sleep onset variability, sleep habits, insomnia symptoms, chronotype, pBMI, depression, anxiety and stress. Hierarchical regression indicated that screentime addiction was significantly associated with increased insomnia symptoms (R2=.642, F=9.95, pDiscussion
Reducing screentime addiction, late night and early morning screentime usage could help improve sleep and wellbeing and reduce obesity in adolescents. This change in screentime practice could be used as a target for a health-promoting intervention.