Synergistic effects of COVID-19 pandemic and sedentary lifestyles on obesity rates among South Korean adults

Since March 2020, South Korea has implemented social distancing measures to reduce the spread of the coronavirus disease (COVID-19). These policies resulted in significant changes in the lifestyle of Korean adults, including spending more time indoors and experiencing increased sedentary time during the pandemic. This study aimed to investigate the combined influence of sedentary lifestyle and the COVID-19 pandemic on obesity rates among adults residing in South Korea. Data were obtained from the 2018–2020 Korea National Health and Nutrition Examination Survey (KNHANES). Multiple logistic regression was used to analyze the synergistic effects of a sedentary lifestyle and COVID-19 on obesity. The prevalence of sedentary lifestyles among the participants increased from 30.4% pre-COVID-19 to 36.6% during the pandemic. Furthermore, the obesity rates were raised independently by COVID-19 (OR: 1.16, 95% CI 1.04–1.30) and by a sedentary lifestyle (OR = 1.17, 95% CI 1.04–1.31). A synergistic effect of a sedentary lifestyle and COVID-19 on obesity was identified (OR: 1.57, 95% CI 1.30–1.85). COVID-19 and a sedentary lifestyle significantly increased the risk of obesity in South Korean adults. Moreover, the combined synergistic effects of these risk factors were too substantial to be disregarded by merely summing their individual effects on obesity.