Joint Association of Change in Physical Activity and Sitting Time with Metabolic Syndrome Risk: A Prospective Cohort Study.

Background and Aims: The purpose of this study was to investigate the combined impact of variations in physical activity (PA) and sitting time (ST) on the risk of developing metabolic syndrome (MetS). Methods: This study was conducted on a cohort of adults from the general population, aged 40-69 years, who participated in the KOGES community-based cohort study over a span of 10 years. Changes in PA and ST were assessed using the results from PA questionnaires completed during baseline and follow-up surveys. The diagnosis of MetS was determined according to the criteria established by the International Diabetes Federation. To evaluate the combined effect of PA and ST changes on the incidence of MetS, we calculated hazard ratios and 95% confidence intervals using a Cox proportional hazards regression model. Result: The incidence of MetS was reduced by 39% (HR = 0.61, 95% CI = 0.46-0.82) for increased ST/increased PA and 26% (HR = 0.74, 95% CI = 0.58-0.94) for decreased ST/increased PA, compared with increased ST/decreased PA, respectively. In addition, this study confirmed that the combined impact of changes in PA and ST, based on the domain of PA, on the incidence of MetS varied. Conclusion: Changes in ST and PA are associated with the risk of developing MetS. These findings lay the groundwork for further research on the relationship between changes in PA, ST, and the occurrence of diseases.