Association Between Social Engagement Frequency and the Risk of Depression in South Korea, the United States, and the United Kingdom: Multinational Evidence From Longitudinal Studies of Aging

Abstract Background Although a greater social engagement is often associated with a reduced risk of depression, longitudinal studies that account for diverse social structures and cultural contexts among middle-aged or older are limited. Methods This study utilized cohort data from the Korean Longitudinal Study of Aging (n = 11,174; 2006–2020) in South Korea (KR), the Health and Retirement Study (n = 42,405; 2004–2019) in the United States, and the English Longitudinal Study of Aging (n = 28,624; 2002–2019) in the United Kingdom, including a total of 29,378 individuals from the population aged ≥45 years. Social engagement frequency was categorized into infrequent, intermediate, and frequent, with changes classified as unchanged, increased, or decreased. The primary outcome was the onset of depression, assessed using the CES-D scale. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated using a Cox proportional hazards regression model. Results In the KR cohort, increased social engagement significantly reduced depression risk only in the infrequent group (KR: HR, 0.20 [95% CI: 0.14–0.28]). However, decreased social engagement elevated depression risk in both the intermediate group (KR: 6.92 [3.73–12.83]; United States: 1.44 [1.16–1.79]) and the frequent group (KR: 1.50 [1.30–1.74]; United States: 1.24 [1.13–1.38]). Conversely, in the UK cohort, increased social engagement raised depression risk in the infrequent group (UK: 1.35 [1.01–1.79]) and intermediate group (UK: 1.63 [1.17–2.27]), whereas decreased engagement lowered depression risk only in the frequent group (UK: 0.80 [0.71–0.90]). Discussion We observed notable national variations in the association between social engagement and depression risk, influenced by cultural and political differences.