Abstract
OBJECTIVE: Our study prospectively assessed the relationship between cumulative handgrip strength and temporal changes in depressive symptoms among adults aged 50 years and over. METHODS: This study was conducted based on two longitudinal cohort studies: the English Longitudinal Study of Ageing (ELSA) and the Survey of Health, Ageing and Retirement in Europe (SHARE). Cumulative handgrip strength was derived from three repeated measurements taken over eight years (ELSA) or six years (SHARE). The mixed linear regression models and Cox regression models were employed to assess the associations between cumulative handgrip strength and temporal changes in depressive symptoms, as well as incident depression risk. RESULTS: Participants in the lowest quartile of cumulative handgrip strength had higher depressive symptom scores compared to those in the highest quartile in ELSA (β: 0.191; 95% CI: 0.035, 0.348) and SHARE (β: 0.391; 95% CI: 0.267, 0.514), and experienced an accelerated increase in depressive symptoms of 0.040 point/y (95% CI: 0.009, 0.070) in ELSA, and 0.067 point/y (95% CI: 0.045, 0.089) in SHARE during follow-up. Regarding incident depression, the lowest quartile group faced a 55% (HR: 1.55; 95% CI: 1.13, 2.12) and 62% (HR: 1.62; 95% CI: 1.38, 1.90) increased risk of developing depression in ELSA and SHARE, relative to the highest quartile. CONCLUSIONS: Reduced cumulative handgrip strength correlated with accelerated depressive symptom progression and increased depression incidence. Future interventional studies should further investigate if strength/muscular fitness can improve mental health, particularly in older adults.