Longitudinal trajectories of social frailty and the risk of all-cause mortality among older adults in South Korea: Exploration of the mediating role of cognitive functioning.

Background

Mounting evidence indicates that social frailty leads to adverse health outcomes in older adults. However, longitudinal trajectories of social frailty and their relationship with all-cause mortality have not been fully investigated. We analyzed the association between social frailty trajectories and all-cause mortality, and the mediating role of cognitive functioning in this relationship.

Methods

A nationally representative sample of older adults in South Korea was analyzed (n = 5,941). Social frailty was measured multidimensionally through social activity, social networks, social support, loneliness, and living alone. Social frailty trajectories from 2006 to 2014 were identified using a growth mixture model. Subsequent change in cognitive functioning was assessed using the Mini-Mental State Examination. Participants were then followed for all-cause mortality through 2022. Cox regression was employed to assess the relationship between social frailty trajectory and all-cause mortality, using hazard ratios (HRs) and 95% confidence intervals (CIs). Mediation analysis was performed to assess the mediating role of poor cognitive functioning.

Results

Two social frailty trajectories were identified: stable-low trajectory (n = 5,065, 85.3%) and high-increasing trajectory (n = 876, 14.7%). Compared to the stable-low social frailty trajectory, the high-increasing social frailty trajectory was linked to an elevated risk for all-cause mortality (HR = 1.32; 95% CI = 1.11-1.57). Subsequent poor cognitive functioning partially accounted for the excess hazard of all-cause mortality among those experiencing a high-increasing social frailty trajectory (proportion mediated: 20.8%, 95% CI: 10.5%-59.5%).

Conclusions

Experiencing an increasing social frailty trajectory was linked to elevated mortality risk in older adults, and subsequent poor cognitive functioning partially accounted for this association.