Association of combined low physical activity and low dietary diversity with mild cognitive impairment among community-dwelling Japanese older adults.

Objective: This study aimed to investigate the potential association between the combination of low physical activity and low dietary diversity with mild cognitive impairment (MCI) in older Japanese adults.

Methods: Data from 600 older adults (mean age 74.1 ± 6.4 years; 62.0% women) were analyzed. We evaluated dietary variety based on the Food Frequency Score (FFS) (maximum 30 points) by assessing the one-week consumption frequencies of ten foods. An FFS of ≤ 16 indicated low dietary diversity. We assessed MCI using the National Center for Geriatrics and Gerontology (NCGG) Functional Assessment Tool. Physical activity levels was determined based on participant responses to two questions: "Do you engage in moderate levels of physical exercise or sports aimed at health?" and "Do you engage in low levels of physical exercise aimed at health?". Participants who responded "No" to both questions were classified as having low physical activity levels. We classified the participants into robust, low-dietary diversity, low-physical activity, and coexistence groups.

Results: The overall prevalence of MCI was 20.7%, with rates in the robust, low dietary diversity, low physical activity, and coexistence groups of 17.7%, 24.7%, 25.0%, and 41.9%, respectively. Multiple logistic regression analysis revealed that low dietary diversity and physical activity were associated with MCI in older adults (odds ratio [OR] 2.80, 95% confidence interval [CI] 1.22-6.28).

Conclusions: The results of the present study demonstrated the association of the co-occurrence of low dietary diversity and low physical activity with MCI. Older adults with both risk factors may require early detection, as well as physical activity and dietary interventions.