Association between Screen Time and Cardiometabolic Risk Factors and Academic Achievement among Children

Abstract

Background: Excessive screen time has been associated with a deleterious impact on cardiometabolic health and academic achievement in children; however, the evidence supporting these effects depends on the type of electronic device. Objective: To examine the association between the time spent watching television (TV) and using interactive electronic devices (computers, tablets, etc.) with cardiometabolic risk factors and academic achievement in school-aged children (8-11 years). Methods/design: Cross-sectional analysis was conducted using baseline measurements from a cluster randomized trial conducted in children in the 4th and 5th grades of primary education from 10 schools in Cuenca Province, Castilla-La Mancha (Spain). Sociodemographic variables, academic achievements, cardiometabolic risk (CMR) indicators, blood pressure and biochemical determinations were measured. Additionally, screen time was measured as TV viewing, electronic device use and overall screen media use and categorized by exposure time as low (< 2 hours), medium (2-3 hours) or high (> 3 hours). Academic achievement was assessed using academic grades that could range from 0 to 10. ANCOVA analyses adjusted for age, SES and BMI, were used to assess differences in anthropometric variables, metabolic variables, and academic achievement across screen time categories by sex. Results: A total of 560 children (51.96% girls) aged 8 to 11 years were examined. The mean total screen time (h/d) for boys was higher (3.89; 95% CI: 3.65-4.13) than that for girls (3.42; 95% CI: 3.21-3.63). For boys, those who watched TV for > 3 hours had worse mean differences than those in the lower categories of watching television in systolic blood pressure (SBP) in mmHg, (-4.09; 95% CI [-7.82, -0.37], p = 0.026), HDL-c levels in mg/dL (8.18; 95% CI [2.25, 14.11], p = 0.003), glucose levels in mg/dL (0.75; 95% CI [-0.86, 2.36], p = 0.79), metabolic syndrome indices in percentage (-3.79; 95% CI [-7.22, -0.35], p = 0.025), and glycated haemoglobin A1c levels in mg/dL (-0.09; 95% CI [-0.18,-0.00], p = 0.046). In addition, boys and girls in the highest category of TV viewing reported worse scores in mathematics (6.50 [SD 1.81] and 6.11 [SD 1.80], respectively) than their peers. When analysing these variables by use of electronic devices and total screen time, most of these relationships disappeared. Conclusion: Our data show that watching TV is the dimension of screen time that is most consistently associated with increased cardiometabolic risk factors and lower academic performance.