Cognitive Reserve Relationship with Physical Performance in Dementia-Free Older Adults: The MIND-China Study

Abstract

Background: Cognitive reserve (CR) may be beneficial to the physical function of the elderly. Objective: We aimed to examine the association of CR proxies and composite CR capacity with physical function in older adults while considering age and sex. Methods: This population-based cross-sectional study included 4,714 participants living in rural China (age≥60 years) who were dementia-free. Structural equation modeling was used to generate a composite CR score by integrating early-life education, midlife occupational complexity, and late-life mental activity and social support. The Short Physical Performance Battery (SPPB) measured physical function. Data were analyzed using linear regression models. Results: Greater educational attainment and mental activity were associated with higher composite SPPB scores and those of its three subtests (p<0.05). Skilled occupations were associated with higher SPPB, chair stand, and walking speed scores, while greater social support was associated with higher scores for SPPB and chair stand (p<0.05). Each 1-point increase in composite CR score (range:-0.77 to 1.03) was linearly associated with a multivariable-Adjusted β-coefficient of 0.74 (95% confidence interval (CI): 0.58-0.89) for total SPPB score, 0.16 (0.10-0.22) for balance test, 0.40 (0.32-0.48) for chair stand, and 0.17 (0.12-0.23) for walking speed. The association between higher composite CR and total SPPB scores was more prominent in those≥75 years than those aged 60-74 years (p<0.01). There was no statistical interaction of composite CR score and sex in physical function. Conclusions: High CR is associated with better physical function, especially among older adults (≥75 years).