Association between social participation and depressive symptoms in Korean middle-aged and older adults: a longitudinal analysis using the Korean longitudinal study of aging, 2010–2024

Objectives Depression imposes a substantial burden on individuals in later life, and social participation has been consistently associated with lower levels of depressive symptoms among middle-aged and older adults. Design Secondary analysis of the Korean Longitudinal Study of Aging. Setting A national public database. Participants We analyzed data of 4,061 community-dwelling adults aged ≥45 years who participated in all waves (2008–2024); baseline characteristics at wave 2 are presented for 3,945 participants (1,627 men and 2,318 women). Primary and secondary outcome measures Depressive symptoms were measured using the 10-item version of the Center of Epidemiologic Studies Depression Scale; a positive screen for depressive symptoms was defined as a score of ≥4. Respondents were categorized into four groups according to social participation transition patterns. Analyses were conducted using the generalized estimating equations approach. Results Compared with sustained non-participation, newly initiating participation (aOR = 0.67, 95% CI: 0.59–0.77) and sustained participation (aOR = 0.76, 95% CI: 0.67–0.86) were associated with lower odds of depressive symptoms, whereas ceasing participation was not significantly associated with depressive symptoms (aOR = 1.07, 95% CI: 0.96–1.21). These associations remained significant after multiple-comparison adjustment, with no evidence of effect modification by sex, and newly initiating participation was also associated with lower odds of moderate and high depressive symptom categories. Conclusion The initiation and maintenance of social participation were associated with lower odds of depressive symptoms in middle-aged and older adults. These findings support social participation as a potential intervention target for the improvement of mental health in this population. Strengths and limitations of this study This study used nationally representative longitudinal data from Korean adults aged 45 years and older and examined changes in social participation over time using transition-based models and multiple sensitivity analyses, allowing a nuanced assessment of initiation, cessation, and sustained participation in relation to depressive symptoms. However, social participation was measured using self-reported items that did not capture the intensity or quality of engagement, depressive symptoms were assessed with a screening scale rather than clinical diagnoses, and the observational longitudinal design cannot exclude bidirectional relationships between social participation and depressive symptoms.