Social network index and its association with cognitive impairment and depressive symptoms in healthy older adults: Age-stratified analysis

Abstract

Background: We investigated associations between the Social Network Index (SNI) and cognitive impairment and depressive symptoms among healthy older adults in South Korea, focusing on distinctions among age subgroups within the older population. Methods: Data were derived from the 2023 National Survey of Older Koreans. From an initial sample of 10,078 adults aged >= 65 years, we excluded proxy respondents, individuals officially registered with disability, classified as frail, and diagnosed with depression, dementia, Parkinson's disease, or two or more other chronic conditions by physician. The final analytic sample comprised 3379 healthy older adults. Multiple logistic regression analyses were conducted to examine associations between SNI and cognitive impairment and depressive symptoms in the full sample, as well as in the subgroups of young-old and middle-old and oldest-old groups. Results: Participants with low SNI had significantly higher odds of cognitive impairment (adjusted odds ratio [aOR] = 1.72; 95% confidence interval [CI]: 1.35-2.18) and depressive symptoms (aOR = 2.35; 95% CI: 1.54-3.59) compared to those with high SNI. These associations remained significant in both young-old (65-74 years; cognitive impairment aOR = 1.79, 95% CI: 1.34-2.37; depressive symptoms aOR = 2.07, 95% CI: 1.24-3.47) and middle-old and oldest-old groups (>= 75 years; cognitive impairment aOR = 1.70, 95% CI: 1.07-2.70; depressive symptoms aOR = 2.85, 95% CI: 1.27-6.42). Conclusions: Our findings underscore the significant associations between social connectedness and cognitive and mental health in later life and suggest that targeted interventions promoting social engagement may be particularly beneficial for older age groups with limited social networks.