Bidirectional Associations between Handgrip Strength and Depressive Symptoms: A Longitudinal Cohort Study

Objectives This study aimed to examine the bidirectional associations between handgrip strength and depressive symptoms in a nationally representative sample. Design Cohort study with a 4-year follow-up. Setting and Participants A total of 13,208 participants from the China Health and Retirement Longitudinal Study were included in the analyses. Methods Depressive symptoms were assessed using the 10-item Center for Epidemiological Studies–Depression Scale. Separate generalized estimating equations were used to analyze the cross-sectional and longitudinal associations between handgrip strength and depressive symptoms. Restricted cubic spline models were performed to explore the shape of the dose-response relationship. Results Decreased handgrip strength was related to subsequent increased risk of depressive symptoms, such that participants in the lowest quartile of handgrip strength were found to have an approximately 36% increased in their risk of depressive symptoms compared with those in the highest quartile [odds ratio (OR) 1.36, 95% confidence interval (CI) 1.17, 1.58]. There was a linear dose-response relationship between handgrip strength and risk of depressive symptoms (Pnonlinearity = .25), in that a 5-unit increment in handgrip strength may lead to an 11% decrease in the risk of depressive symptoms (OR 0.89, 95% CI 0.85, 0.92). Conversely, depressive symptoms were prospectively associated with subsequent decreased handgrip strength (β = −0.84, 95% CI –1.13, −0.55). An approximatively L-shaped dose-response pattern was found for the association between depressive symptoms level and handgrip strength (Pnonlinearity = .02). Conclusions and Implications The present study identified bidirectional associations between handgrip strength and depressive symptoms, and the associations were found to have a dose-response pattern. It provides important insights into integrated mental and physical health intervention strategies that simultaneously promote handgrip strength and depressive symptoms.