Joint associations of handgrip strength and functional disability with cognitive impairment in older adults

BACKGROUND: Handgrip strength (HGS) and functional disability may reflect interconnected biological processes contributing to functional decline. However, the extent to which their co-occurrence predicts cognitive impairment in aging populations remains unclear. This study investigated the joint association of low HGS and functional disability with cognitive impairment in a nationally representative cohort of older Chinese adults. METHODS: We analyzed data from the China Health and Retirement Longitudinal Study (2011-2020), including participants aged ≥ 60 years. Based on baseline HGS and functional disability status, participants were categorized into four groups. Logistic regression and Cox proportional hazards models were used to examine cross-sectional and longitudinal associations with cognitive impairment, respectively. Cognitive trajectories were assessed using linear mixed-effects models, and subgroup analyses evaluated the consistency of associations across demographic and clinical strata. RESULTS: A total of 2423 participants (mean age 65.4 ± 4.7 years; 44.1% female) were included. In cross-sectional analyses, compared with participants without low HGS or functional disability, the adjusted odds ratios (OR) for cognitive impairment were 1.62 (95% confidence interval CI: 1.23-2.13; P < 0.001) for functional disability alone, 1.81 (95% CI 1.35-2.41; P < 0.001) for low HGS alone, and 2.81 (95% CI 2.07-3.83; P < 0.001) for both conditions. Over nine years of follow-up, the corresponding adjusted hazard ratios (HR) for incident cognitive impairment were 1.52 (95% CI 1.16-1.99), 1.63 (95% CI 1.21-2.20), and 1.73 (95% CI 1.16-2.59), respectively. Linear mixed-effects models indicated significant differences in cognitive trajectories among groups, with participants having both conditions consistently maintaining the lowest standardized cognitive scores. Subgroup analyses demonstrated consistent associations across stratified analyses. CONCLUSION: The joint presence of low HGS and functional disability was strongly associated with an elevated risk of cognitive impairment. Incorporating combined assessments of muscle strength and functional status into routine geriatric evaluations may enable earlier risk stratification and inform comprehensive interventions to preserve cognitive health.