Joint Association of Sedentary Time and Physical Activity with Metabolic Syndrome Among Korean Adults: A Cross-Sectional Analysis of the 2024 Korea National Health and Nutrition Examination Survey

Abstract

Highlights What are the main findings? Participants with high sedentary time who did not meet the physical activity recommendation had higher odds of metabolic syndrome than the low sedentary time/meeting recommendation group after adjustment for sociodemographic factors and health-related behaviors. No statistically significant multiplicative or additive interaction between sedentary time and physical activity was observed. In sensitivity analysis, longer sedentary time assessed continuously was associated with higher odds of metabolic syndrome. What are the implications of the main findings? Sedentary time and physical activity should be considered jointly when assessing metabolic health, but the present findings do not provide evidence that physical activity modifies or offsets the association between sedentary time and metabolic syndrome. Prospective studies using more detailed or objective measures of sedentary time and physical activity are needed to clarify dose–response relationships and their combined associations with metabolic health. Abstract Background/Objectives: This study examined the joint association of sedentary time and physical activity with metabolic syndrome among Korean adults and whether physical activity modified this association. Methods: This cross-sectional study analyzed 2024 Korea National Health and Nutrition Examination Survey data from 3075 adults aged ≥19 years. Participants were classified into four groups by sedentary time and physical activity recommendation status. Complex-sample logistic regression was performed, with additional analyses of independent associations, interactions, and sensitivity analyses. Results: Compared with the low sedentary time/meeting group, the high sedentary time/not meeting group had higher odds of metabolic syndrome after adjustment for sociodemographic and health-related factors (OR = 1.38, 95% CI: 1.07–1.78; p = 0.013). No significant multiplicative interaction was observed (interaction OR = 1.08, 95% CI: 0.74–1.57; p = 0.681), and additive interaction indices were also nonsignificant. Each additional hour/day of sedentary time was associated with 4% higher odds of metabolic syndrome (OR = 1.04, 95% CI: 1.01–1.07; p = 0.011). After additional BMI adjustment, the association for the high sedentary time/not meeting group was not statistically significant (OR = 1.34, 95% CI: 0.98–1.83; p = 0.065). Conclusions: High sedentary time combined with not meeting the physical activity recommendation was associated with higher odds of metabolic syndrome. However, no significant multiplicative or additive interaction was identified. These findings support joint consideration of sedentary time and physical activity without implying that physical activity offsets the association of prolonged sedentary time with metabolic syndrome.