Cognitive impairment increased the odds of poor physical performance by 2.45-fold, demonstrating that cognitive decline impacts physical function more strongly than the reverse.
Cross-Sectional (n=20,671)
Yes
The study reveals an asymmetric bidirectional relationship where cognitive impairment more strongly predicts physical decline than vice versa, identifying critical cognitive thresholds for targeted interventions.
Effect estimate: OR 2.45 (95% CI 2.22-2.70)
p-value: p=<.001
Background: The global aging population faces increasing risks of cognitive and physical decline, yet the bidirectional and nonlinear dynamics between these domains remain poorly understood. Objective: This study aims to investigate the bidirectional and nonlinear associations between cognitive function and physical performance in older adults and to identify threshold effects and population subgroups at elevated risk. Methods: This multicenter study of 20,868 older adults in China analyzed the bidirectional asymmetric and threshold-response associations between cognitive and physical function using logistic or linear regression and restricted cubic spline, with subgroup and interaction analyses. Results: The study revealed an asymmetrical bidirectional relationship between cognitive function and physical performance, with cognitive impairment having a stronger association with physical function (Short Physical Performance Battery SPPB, odds ratio OR 2.45, P<.05 vs 1.16,P=.051; gait speed: OR 2.36,P<.05 vs 1.89, P<.050). Restricted cubic spline analysis identified 3 key inflection points at Mini-Mental State Examination (MMSE) scores of 19, 24, and 29. When MMSE <24, cognitive improvement significantly protected physical performance (SPPB: OR 0.86, 95% CI 0.84-0.87; gait speed: OR 0.84, 95% CI 0.82-0.85). The critical intervention window was between MMSE 19-24 (SPPB, OR 0.66, 95% CI 0.57-0.77). At MMSE ≥24, balance protection remained significant (OR 0.69, 95% CI 0.68-0.70), but overall physical performance showed diminished effects, with SPPB demonstrating a weaker, marginal association (P=.051). A paradoxical reversal effect was observed for gait speed (OR 1.05, 95% CI 1.04-1.07). High-income (OR 5.24, 95% CI 3.91-7.02) and high-education subgroups (OR 3.98, 95% CI 1.48-10.70) exhibited heightened vulnerability. Conclusions: This study demonstrates a bidirectional, asymmetric relationship between cognitive function and physical performance, identifies a nonlinear threshold effect, and highlights population heterogeneity.
Hu et al. (Thu,) conducted a cross-sectional in Cognitive and physical decline (n=20,671). Cognitive impairment vs. Normal cognitive function was evaluated on Poor physical performance (SPPB score 0-9) (OR 2.45, 95% CI 2.22-2.70, p=<.001). Cognitive impairment increased the odds of poor physical performance by 2.45-fold, demonstrating that cognitive decline impacts physical function more strongly than the reverse.