Abstract Body: Background: This study aimed to (1) examine the direct association between total screen time and cognitive function in U.S. adolescents and (2) evaluate whether blood pressure mediates this relationship, highlighting a potential physiological mechanism linking screen-related behaviors to cognitive function during adolescence.
Methods: We analyzed data from 4,721 participants from the ABCD Study, recruited across 21 U.S. cities between 2018 and 2020. The average age was 9.9 years, and data from the baseline and second follow-up were used. Cognitive function, the primary outcome, was assessed using the NIH Toolbox and age-adjusted scores. The main exposure was screen time, analyzed as a total measure and across individual domains (video games, TV, phone use, and social media). Blood pressure levels (systolic and diastolic) were examined as potential mediators. Linear regression models were used to estimate associations between screen time and cognitive function, and structural equation modeling was applied to test the mediating role of blood pressure in these associations. These scores were all adjusted for based on age.
Results: All individual domains of screen time demonstrated a significant negative association with cognitive function scores. Specifically, higher screen time was associated with lower cognitive function for video games (β = -2.78; 95% CI, -3.40 to -2.20), social media (β = -5.30; 95% CI, -6.10 to -4.50), television (β = -3.60; 95% CI, -4.40 to -2.80), phone use (β = -4.44; 95% CI, -5.10 to -3.80), and total screen time (β = -4.36; 95% CI, -4.90 to -3.80). These are unstandardized coefficients, representing the expected difference in cognitive function score compared to the reference group (low screen time), holding all other variables constant. Mediation analysis revealed a small but statistically significant indirect effect of blood pressure on the relationship between screen time and cognitive function for both social media (1.12%) and total screen time (1.21%), suggesting that hypertension may partially mediate these associations.
Conclusion: Screen time was negatively associated with cognitive function in U.S. adolescents, with the strongest effects seen for social media use. Blood pressure significantly mediated the relationship between screen time (particularly social media and total screen use) and executive function, suggesting cardiovascular health as a physiological mechanism pathway linking screen time with cognitive health.