Asymmetric associations of depressive symptoms with frailty and the moderating roles of marriage and gender: A longitudinal study of older Korean adults.

BACKGROUND

Depressive symptoms are a well-established risk factor for frailty in later life, yet most studies treat depression as a static condition and overlook potential asymmetries in the effects of increasing and decreasing symptoms on physical vulnerability. This study examines the asymmetric effects of changes in depressive symptoms on frailty and investigates whether these associations are moderated by marital status and gender among older adults in South Korea.

METHODS

We used seven waves of the Korean Longitudinal Study of Ageing (KLoSA), focusing on 6756 adults aged 53 and older at baseline. Frailty was measured using a 37-item deficit accumulation index. Depressive symptoms were assessed with the 10-item CES-D scale. Asymmetric fixed effects models were employed to differentiate the effects of increases and decreases in depressive symptoms. Interaction terms were included to test moderating effects of marital status and gender.

RESULTS

Increases in depressive symptoms were associated with significantly higher frailty, whereas decreases were associated with more modest reductions. These asymmetric associations between depressive symptoms and frailty were statistically significant. Marital status moderated this association: being married attenuated the association between increasing depressive symptoms and frailty. Gender-stratified and interaction models revealed that this protective association of marriage was significant among women but not among men.

CONCLUSIONS

Findings highlight the asymmetric nature of the depression-frailty link and underscore the importance of marital and gender contexts. These findings point to the value of early identification of worsening depressive symptoms and attention to relational supports, particularly among older adults who are unmarried.