Did the increase in sitting time due to COVID-19 lead to obesity in adolescents?

INTRODUCTION: Since adolescent with obesity is closely linked with the incidence of cardiovascular disease, it is important to identify the factors that increase the prevalence of adolescent with obesity and prevent it early. This study aimed to examine which of the demographic and lifestyle factors including sitting hours per week for purposes other than study had the greatest influence on Korean adolescents with obesity during the coronavirus disease 2019 (COVID-19) pandemic. METHODS: We used the Korean Youth Risk Behavior Web-based Survey (KYRBWS) data. The primary outcome was the relationship between sitting hours and obesity during and after the COVID-19 pandemic. Multiple logistic regression analysis was performed to examine which of the demographic and lifestyle factors including sitting hours per week for purposes other than study had the greatest influence on Korean adolescents’ obesity status. RESULTS: The prevalence of obesity was significantly higher during the COVID-19 than before the COVID-19 (OR, 1.268, CI:1.232–1.305). There was a significant increase in the OR for sitting hours per week for purposes other than study (OR, 1.021, 95% CI, 1.019–1.024). Compared to low household income, the OR decreased for middle (OR = 0.798, 95% CI:0.77, 0.826) and high-income household students (OR, 0.833, 95% CI: 0.803–0.865). DISCUSSION/CONCLUSION: The results of this study confirmed the relationship between sit-ting hours and obesity in adolescents during the pandemic. To prevent adolescent with obesity, further studies are needed to focus on the importance of promoting health policy in adolescents to avoid the continuous rising of its prevalence and needed to understand whether the increase in obesity rates during the pandemic is a temporary trend. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12887-022-03807-z.