Examining Multilevel Influences on Depressive Symptoms Among Korean Older Adults: The Interplay of Individual and Regional Factors.

: This study investigates how individual- and regional-level factors jointly influence depressive symptoms among older adults in South Korea, a rapidly aging society facing growing mental health concerns. : Multilevel structural equation modelling with Monte Carlo confidence interval testing is used to analyze a cross-sectional, secondary dataset of 600 Korean older adults aged 65 years. The data come from the 2020 Ewha Study of Intergenerational Issues (ESoII), which is collected using multistage-quota sampling by age, gender, and region to ensure population representativeness across 14 cities and provinces. : Significant direct and indirect effects are observed at both individual and regional levels. At the individual level, aging anxiety is associated with social isolation (β = 0.208, > 001) and depressive symptoms (β = 0.224, < 0.001); social isolation is also associated with depressive symptoms (β = 0.288, > 0.001), and mediates the relationship between aging anxiety and depression (95% CI = [0.016, 0.065]). At the regional level, age-friendly environments are associated with social isolation (β = -0.287, < 0.05), which in turn is associated with depressive symptoms (β = 0.403, < 0.01). The mediation effect of social isolation in the relationship between age-friendly environments and depressive symptoms is statistically significant (95% CI = [-0.022, -0.004]). : The findings suggest that social isolation is a key mechanism linking both psychological and environmental risk factors to depression in later life. Promoting age-friendly environments may be an effective strategy for reducing social isolation and improving mental health outcomes among older adults. Interventions should consider both individual vulnerabilities and structural supports.