The role of depression in the association between handgrip strength and mild cognitive impairment among Chinese older adults

BACKGROUND: Handgrip strength (HGS) is an accessible marker of muscle function and a potential indicator of cognitive health in older adults. However, the relationship between HGS and mild cognitive impairment (MCI) and the potential role of depression in that association, remains unclear. METHODS: In this cross-sectional study, 1289 Chinese older adults were recruited between April 2024 and June 2025. HGS was measured using an electronic hand dynamometer, depression was assessed using the 15-item Geriatric Depression Scale, and cognitive function was evaluated using the Mini-Mental State Examination. Logistic regression, restricted cubic splines, stratified analyses, and joint association analyses were performed. An exploratory mediation analysis was conducted to examine whether depression was associated with the relationship between HGS and cognitive function. RESULTS: Participants had a mean age of 73.27 ± 12.11 years, and 41.82% were male. Higher absolute and relative HGS were independently associated with lower odds of MCI (highest vs. lowest quartile: OR = 0.40, 95%CI: 0.25, 0.64; OR = 0.47, 95%CI: 0.30, 0.74, respectively; P for trend < 0.001). Dose-response analyses revealed linear inverse associations. Joint analyses showed that coexisting HGS weakness/decreased relative HGS and depression was associated with the highest odds of MCI. Exploratory mediation analyses suggested that depression statistically explained part of the association between HGS and cognitive function, with an estimated proportion mediated of 20.4% for absolute HGS and 19.7% for relative HGS. CONCLUSIONS: Both absolute and relative HGS are inversely associated with odds of MCI in Chinese older adults, and depression appeared to account for a portion of these cross-sectional associations. Prospective and interventional studies are needed to determine whether changes in HGS or depression lead to subsequent improvements of cognitive outcomes.