Impact of covid-19 on obesity and abdominal obesity: focusing on differences by age group

BACKGROUNDS: During the COVID-19 pandemic, the implementation of social-distancing policies has led to escalating the prevalence of obesity. Especially, social changes caused by COVID-19 would have had different effects depending on age. Therefore, this study aims to analyze the prevalence of obesity that has increased during the pandemic according to age group. METHODS: The study subjects were Korean adults aged 19 to 64 years who participated in the 2019 to 2020 Korean National Health and Nutrition Examination Survey (KNHNES). The definition of obesity, morbid obesity, and abdominal obesity were defined using Asian-Pacific guidelines. The age group was divided into under 40 years old and over 40 years old. We analyzed the odds ratio (ORs) (95% confidence intervals (CIs)) to compare the variants between before (2019) and after (2020) COVID-19. RESULTS: The prevalence of obesity, morbid obesity, and abdominal obesity increased in 2020 compared to 2019 among the Korean population. In multivariable analysis, the rate of obesity and abdominal obesity increased in both groups whom under 40 years old and over 40 by OR of 1.23 (95% CI, 1.09-1.40) and 1.23 (95% CI 1.07-1.40). However, the rate of morbid obesity only increased in adults younger than 40 years old by an OR of 1.45 (95% CI, 1.05-2.01). The achievement rate of aerobic physical activity decreased in 2020 for both age groups(<40: from 55.8% to 52.7%, ≥40: from 42.7% to 41.3%). Notably, men showed a decrease in the achievement rate of aerobic physical activity in 2020 (OR 0.82, 95% CI, 0.69-0.97) compared to 2019. CONCLUSIONS: Our study shows the increase in the prevalence of obesity during the COVID-19 pandemic and morbid obesity among those under the age of 40. We found a decrease in aerobic physical activity in 2020 compared to that in 2019. In Korean men, further evaluation might be necessary to determine the associated factors affecting the increased prevalence of obesity during the COVID-19 pandemic period. KEY MESSAGES: • The prevalence of obesity increased during the COVID-19 pandemic in Korea, with a rise in the incidence of morbid obesity among those under the age of 40. • The achievement rate of aerobic physical activity decreased in 2020 compared to that in 2019.