Frailty and depressive symptoms multitrajectories with cognitive function in couples: Findings from the China health and retirement longitudinal study.

BACKGROUND

Both frailty and depressive symptoms are concurrently associated with the decline in cognitive function. Most existing studies have focused on individual-level analyses rather than dyadic investigations among couples. This study aims to explore the longitudinal developmental patterns of frailty and depressive symptoms in couples and further examine cognitive function trajectories across these distinct multitrajectory groups.

METHODS

Based on longitudinal data of 5828 couples from the China Health and Retirement Longitudinal Study from 2011 to 2020, group-based trajectory modeling (GBTM) was applied to identify heterogeneous multitrajectories of frailty and depressive symptoms among wives and husbands.

RESULTS

Four distinct frailty-depression multitrajectory groups (G1-G4) were identified. Within-dyad cognitive decline slope correlation was r = 0.567 (P < 0.001). After adjusting for sociodemographic and lifestyle characteristics (Model 2), all trajectory groups (G2-G4) exhibited significantly poorer bilateral cognitive function compared to the robust G1 group (all P < 0.001). Significant sex asymmetry emerged in trajectory × time interactions: Relative to the G1 reference, wives in the progressive frailty-depression group (G3) showed an additional annual cognitive decline of 0.125 units (P < 0.001), whereas husbands in the progressive group (G4) declined 0.288 units/year faster than G1 husbands (P < 0.001). A three-way interaction model (trajectory × time × sex) confirmed this asymmetry: G3 wives declined faster than their husbands (β = -0.099, P = 0.004), and G4 husbands displayed sharper cognitive decline (β = 0.237, P < 0.001).

CONCLUSION

Frailty and depressive symptoms co-occur with cognitive decline among couples. Moreover, the rate of cognitive decline differs between wives and husbands across distinct marital dyadic patterns.