National Trends in the Prevalence of Screen Time and Its Association With Biopsychosocial Risk Factors Among Korean Adolescents, 2008-2021.

PURPOSE

Prior studies suggested an increase in screen time among adolescents during the COVID-19 pandemic; however, due to limited sample size and a short-term observation period, these associations are inconclusive and inconsistent. Thus, we aimed to compare screen time during the pandemic and the long-term trend through a Korean large-scale and long-term study of one million adolescents.

METHODS

Data from 2008 to 2021 on 913,191 Korean adolescents aged 12-18 years were obtained via a nationwide, large-scale, and serial study. We investigated the change of screen time use over time and the change in trend before and during the pandemic (2008-2019 vs. 2020-2021) by using weighted linear regression model with estimates of β-coefficients and 95% confidence intervals (CIs). Moreover, we analyzed the differences in vulnerability of biopsychosocial factor before and during the pandemic.

RESULTS

A total of 913,191 adolescents were included in this analysis. During the pandemic, the overall screen time of Korean adolescents significantly increased compared to the expected based on the prepandemic period during the pre-COVID-19 period (weighted screen time before the pandemic [133.24 min/day; 95% CI, 132.08-134.40] vs. during the pandemic [303.66 min/day; 95% CI, 300.59-306.73]; β 0.331; 95% CI, 0.311-0.351). Comparing before and during the pandemic, potential risk factors associated with screen exposure included female sex, sadness, suicidal thoughts, alcohol consumption, low educational level of parents, low level of vigorous physical activity, middle school students, and low household income.

DISCUSSION

Through large-scale nationwide study, this study described the 14-year trend of screen time among Korean adolescents. In the era of COVID-19, the prevalence of screen exposure has been increasing more rapidly than before at the population level. Also, the pandemic amplified the differences in screen time across grade, sex, sadness, suicidal thoughts, smoking, alcohol consumption, education level of parents, physical activity, and household income groups.