Association of sleep and plant-based diet with cognitive function in older adults-Based on a national cohort study.

Background and objectives: To explore the relationship between sleep, plant-based diets, and cognitive function in the elderly, addressing the challenges of global aging.

Methods and study design: Using data from the 2005 China Longitudinal Healthy Longevity Survey (CLHLS), cognitive function was assessed with the Mini-Mental State Examination (MMSE), dietary patterns through a short-form FFQ, and sleep duration and quality via self-report measures. A Cox regression model analyzed the associations between sleep, plant-based diet, and cognitive function, with mediating effect analysis to explore these relationships further.

Results: A total of 5911 subjects were included in the study. In both univariate and multivariate Cox regression analysis, the sleep quality with average level (HR=1.26; 95%CI=1.06-1.48), sleep duration (HR=1.03; 95%CI=1.01-1.05), the unhealthful plant-based diet index (uPDI) (HR=1.02; 95%CI=1.01-1.03), the healthful plant-based diet index (hPDI) (HR=1.01; 95%CI=1.00-1.03), and the plant-based diet index (PDI) (HR=0.99; 95%CI=0.97-1.00) were always significantly correlated with cognitive function. The sleep quality with bad level (HR=1.28; 95% CI=1.03-1.58) was associated with cognitive function only in multivariate Cox regression analysis. In the mediating analysis, PDI and hPDI had a significant overall effect on cognitive function, and the proportion mediated by sleep duration were about 4.4% (95%CI=0.01-0.15) and 7.92% (95%CI=0.03-0.25).

Conclusions: A significant correlation exists between sleep, plant-based diets, and cognitive function in older adults, with sleep duration mediating the relationship between diet and cognitive function. These findings emphasize the role of diet and sleep in preventing cognitive decline in the elderly.