Change of obesity prevalence and lifestyle patterns before and during COVID-19 among Korean adolescents

Purpose: Lockdown measure for limiting coronavirus disease 2019 ( COVID-19) spread cause an aggravation of the childhood obesity epidemic through lifestyle changes. The aim is to investigate how social restriction might have changed obesity prevalence and lifestyle patterns in Korean adolescents. We also evaluate the most fragile group and most influencing lifestyle parameters on obesity prevalence. Methods: To assess the change in weight status and lifestyle, we compared the Korea Youth Risk Behavior Web-based Survey data 2019 (pre- COVID-19, n=57,303) and 2020 (post-COVID-19, n=54,948). Participants from middle schools and high schools, aged 12 to 18 years, voluntarily reported their weight status and lifestyles. Results: The prevalence of obesity of the total subjects was 11.0% in 2019 and 12.1% in 2020. This prevalence difference varied by sex (males 1.8%, females 0.3%, P<0.001), age group (12-15 year 1.6%, 16-18 year 0.4%, P<0.001), and socioeconomic status. Male aged 12-15 years showed highest increase from 12.5% to 15.2%. Physical activities, fruit intake, consumption of sugar-sweetened beverages, and stress showed all decrease. Only, nonstudy sedentary time marked increased from 3.3 +/- 2.3 hr/day to 4.3 +/- 2.8 hr/day. Both moderate-intensity and vigorous-intensity physical activity marked decreased especially in male aged 12-15 years, while increased in female aged 16-18 years. Conclusion: Korean adolescents showed increasing obesity prevalence after COVID-19 lockdown, with males aged 12-15 years mainly affected, mainly due to a reduced physical activity and increased sedentary time.