Social Relationships, Depressive Symptoms, and Self-Rated Health Among Adults Living Alone in South Korea: An Analysis of the 2025 Korea Community Health Survey

Background/Objectives: Social relationships may be associated with psychological and perceived general health among adults living alone. This study examined the associations of contact frequency with family members or relatives, neighbors, and friends, and perceived neighborhood trust with depressive symptoms and self-rated health among adults living alone in South Korea, including potential age-related differences. Methods: Data from 44,168 adults living alone who participated in the 2025 Korea Community Health Survey were analyzed. Complex-samples regression models accounted for stratification, clustering, and sampling weights. Clinically relevant depressive symptoms were defined as a Patient Health Questionnaire-9 score of 10 or higher. Poor self-rated health was assessed separately. Multivariable models adjusted for demographic, socioeconomic, and selected health-related characteristics. Age-related interactions and sensitivity analyses were also examined. Results: The survey-weighted prevalence of depressive symptoms was 6.9%, while that of poor self-rated health was 22.5%. Compared with contact four or more times per week, family or relative contact less than once per month was associated with higher odds of depressive symptoms (adjusted odds ratio [aOR] = 1.50, 95% confidence interval [CI]: 1.31–1.72) and poor self-rated health (aOR = 1.28, 95% CI: 1.17–1.41). Infrequent friend contact showed stronger associations with both outcomes (aOR = 2.02 and 1.77, respectively). Perceived neighborhood trust was associated with both outcomes, with significant age-related differences. Sensitivity analyses generally supported the principal findings. Conclusions: Distinct social relationship indicators were associated with depressive symptoms and self-rated health among adults living alone. These cross-sectional findings highlight the importance of differentiating interpersonal contact domains and neighborhood trust without implying causal effects.