Screen Time Is Associated With Cardiometabolic and Cardiovascular Disease Risk in Childhood and Adolescence

Background Screen time in children and adolescents may be linked to cardiometabolic and cardiovascular risk. Methods We analyzed data from >1000 participants in the COPSAC2010 and COPSAC2000 (Copenhagen Prospective Studies on Asthma in Childhood) mother–child 2000 and 2010 cohorts. Discretionary screen time, reported by parents or self, was assessed in relation to a composite cardiometabolic risk score based on Z scores of waist circumference, systolic blood pressure, high‐density lipoprotein cholesterol, triglycerides, and glucose. Secondary outcomes included insulin resistance, inflammation, lipoproteins, and anthropometry. A predicted cardiovascular risk score, derived from Cox models trained on UK Biobank data, was also assessed as an outcome. We evaluated whether lifestyle factors (sleep, physical activity, diet, puberty) moderated these associations. Blood nuclear magnetic resonance metabolomics were modeled using supervised machine learning to identify a metabolic screen‐time signature. Results Each additional hour of screen time was associated with higher cardiometabolic risk in both children (β=0.08 [0.01–0.14], P =0.021) and adolescents (β=0.13 [0.07–0.20], P =0.001). Sleep duration significantly moderated this association in both cohorts (childhood: P =0.029; adolescence: P =0.012), with higher risk among those with shorter sleep. Screen time was also associated with higher predicted cardiovascular risk in adolescence (β=0.07 [0.01–0.13], P =0.017). A screen time‐associated metabolomic signature identified in childhood was validated in adolescence (β=0.14 [0.03–0.26], P =0.014). Conclusions Screen time was positively associated with cardiometabolic and cardiovascular risk, and these associations were stronger among children and adolescents with shorter sleep duration. These findings highlight the importance of jointly considering screen time and sleep patterns in the assessment of early‐life risk factors for cardiometabolic and cardiovascular health.