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 (P-nonlinearity = .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 (beta = -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 (P-nonlinearity = .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. (C) 2021 AMDA - The Society for Post-Acute and Long-Term Care Medicine.