Abstract
Background: Amidst aging populations, late-life depression's yearly rise challenges senior health and strains healthcare systems. In light of this, there is an urgent need to identify and intervene in modifiable risk factors to alleviate this issue. This study aims to investigate the mediating role of pulmonary function in the longitudinal relationship between grip strength and depression.
Methods: We analyzed data from 6,313 CHARLS participants aged ≥60 from 2015-2018 waves, using linear regression and mediation analysis with 1,000 bootstraps to assess pulmonary function's mediation in grip strength-depression link.
Results: After adjusting for confounding variables, grip strength was found to be negatively associated with subsequent depressive symptom severity (β = -0.215, P < 0.001) and positively correlated with Pulmonary Function (β = 3.367, P < 0.001). Pulmonary Function's moderating effect accounted for 13.59% of the total effect between grip strength and depression. The size of the indirect effect was estimated at -0.034 (95% CI: -0.048, -0.022), indicating a statistically significant mediation.
Limitation: Our mediation analysis assumes linear relationships, though real-world dynamics are often multidimensional and nonlinear, possibly involving complex interactions.
Conclusion: Grip strength directly affects depression and indirectly via pulmonary function. To tackle senior depression, interventions should boost grip strength and lung function. Routine grip tests and promoting aerobic/resistance exercises to seniors can help maintain pulmonary function and healthy aging.