Longitudinal changes in screen time, sleep, and sports/exercise activity in early adolescence

BACKGROUND: This study aimed to examine longitudinal changes in screen time, sleep, and sports/exercise activity in early adolescents in the United States. METHODS: We examined data over four annual assessments collected from the Adolescent Brain Cognitive Development (ABCD) Study (N = 9,519) from baseline (2016–2018, ages 9–10) to Year 3 (2019–2021, ages 12–13). Trends in screen time, sleep, sports/exercise activity, and other activities in a 24-hour time-use paradigm were derived from compositional data analysis, incorporating isometric log-ratio transformations and mixed-effects modeling. RESULTS: Screen time increased by 0.23 h/day from baseline to Year 1, 1.58 h/day from baseline to Year 2, and 3.28 h/day from baseline to Year 3. Video game playing increased more in boys, and digital socializing increased more in girls. Sleep duration slightly decreased from baseline to Year 3. Sports/exercise activity slightly decreased from baseline to Year 1, then increased until Year 3. Time spent on other activities decreased by 0.13 h/day from baseline to Year 1, 1.60 h/day from baseline to Year 2, and 3.38 h/day from baseline to Year 3. CONCLUSIONS: Our findings indicate screen time may have increasingly displaced other activities as early adolescents age.