Multilevel Factors Associated with Obesity among South Korean Adolescents before and during the COVID-19 Pandemic.

Background: Coronavirus disease 2019 (COVID-19)-necessitated lockdowns and school closures have limited social interactions among adolescents, which result in unhealthy behaviors. This study compared the multilevel factors associated with obesity among adolescents in South Korea before and during the pandemic. Method: We applied the social-ecological model and analyzed the 2019 and 2020 Korea Youth Risk Behavior Web-based Survey (KYRBS), including middle and high school students. We considered factors at the individual, family, and community levels in the logistic regression. Age and gender-adjusted obesity (body mass index ≥ the 95th percentile) was the dependent variable. Result: The prevalence of obesity slightly increased from 11.31% before the pandemic to 12.48% during it; the odds of obesity were 1.12 times (95% confidence interval [CI] = 1.08-1.16) as high during the pandemic compared to before it. Several individual factors ( e.g. , age, gender, fast-food consumption) and perceived family economic status were commonly associated with obesity before and during the COVID-19 pandemic. Physical activity and city type were related to obesity only before the pandemic. Downgraded economic status owing to COVID-19 was adversely related to obesity during the pandemic. Conclusion: Inclusive multilevel support is needed to combat obesity in adolescence during the pandemic and those economically impacted require additional support.