Identifying Subgroups With Prolonged Sedentary Time Among South Korean Adults: A Decision Tree Analysis

This study aimed to identify factors and conditional subgroup patterns associated with prolonged sedentary time among South Korean adults using decision tree analysis. This descriptive cross-sectional study included 700 adults recruited using proportional quota sampling by region, sex, and age. Data were collected through an online survey. Sedentary time was assessed using a self-reported item from the Global Physical Activity Questionnaire, whereas perceived stress and depressive symptoms were measured using validated scales. Prolonged sedentary time was defined as sedentary time exceeding 8 hours per day. Descriptive statistics, analysis of variance, Pearson’s correlation analysis, and classification and regression tree (CRT) analysis with split-sample validation were performed. Women, younger adults, participants with lower incomes, unmarried individuals, and those reporting very low exercise intensity had longer sedentary time. Perceived stress was positively correlated with depressive symptoms and sedentary time, whereas depressive symptoms showed a weak positive correlation with sedentary time. Exercise intensity was the first splitting variable for prolonged sedentary time in the decision tree, followed by age, depressive symptoms, sex, marital status, and perceived stress. The subgroup characterized by very low exercise intensity, younger age, and higher depressive symptoms had the highest proportion of prolonged sedentary time (83.3%). These findings provide exploratory evidence of conditional subgroup patterns associated with prolonged sedentary time among South Korean adults. Longitudinal studies using objective measures of sedentary time are needed to confirm these findings.