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

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).