Adherence to High Dietary Diversity and Incident Cognitive Impairment for the Oldest-Old: A Community-Based, Nationwide Cohort Study

Abstract

Background and aims: Dietary diversity change is associated with cognitive function, however, whether the effect still exists among the oldest-old (80+) is unclear. Our aim was to examine the effect of dietary diversity changes on cognitive impairment for the oldest-old in a large prospective cohort. Methods: Within the Chinese Longitudinal Healthy Longevity Study, 6237 adults older than 80 years were included. The dietary diversity score (DDS) was assessed by a simplified food frequency questionnaire (FFQ). Cognitive impairment was defined as a Mini-Mental State Examination (MMSE) score lower than 18 points. Cognitive decline was defined as a reduction of total MMSE score ≥3 points, and cognitive decline of different subdomains was defined as a reduction of ≥15% in the corresponding cognitive domain. The multivariate-adjusted Cox proportional hazard model evaluated the effects of DDS change on cognitive decline. The linear mixed-effect model was used to test subsequent changes in MMSE over the years. Results: During 32,813 person-years of follow-up, 1829 participants developed cognitive impairment. Relative to the high–high DDS change pattern, participants in the low–low and high–low patterns were associated with an increased risk of cognitive impairment with a hazard ratio (95% confidential interval, CI) of 1.43 (1.25, 1.63) and 1.44 (1.24, 1.67), and a faster decline in the MMSE score over the follow-up year. Participants with the low–high pattern had a similar incidence of cognitive impairment with HRs (95% CI) of 1.03 (0.88, 1.20). Compared with the stable DDS status group (−1–1), the risk of cognitive impairment was higher for those with large declines in DDS (≤−5) and the HR was 1.70 (95% CI: 1.44, 2.01). Conclusions: Even for people older than 80, dietary diversity change is a simple method to identify those who had a high risk of cognitive decline. Keeping high dietary diversity is beneficial for cognitive function and its subdomain even in the final phase of life, especially for females and the illiterate oldest-old.

Association of dietary patterns with cognitive function in older people: Results from the Chinese longitudinal healthy longevity survey

“…Similar to our findings, Song et al. noted a stronger association between DDS changes and cognitive impairment risk in illiterate individuals [48]. Fourth, malnutrition contributes to poorer cognitive function, and low BMI can signal inadequate nutrition.…”

“…Third, higher education levels often denote cognitive reserve, offsetting the impact of brain damage on cognition [49]. Similar to our findings, Song et al noted a stronger association between DDS changes and cognitive impairment risk in illiterate individuals [48]. Fourth, malnutrition contributes to poorer cognitive function, and low BMI can Abbreviations: CI, confidence interval; OR, odds ratio.…”

“…This could be due to U‐H subgroup individuals altering diets and adopting positive behaviors such as increased activity, contributing to significant MMSE score improvement. This echoes a study where low‐high DDS patterns showed the smallest MMSE decline [48]. The tandem shifts in diet and cognitive decline highlight the potential cognitive benefits of a balanced diet and dietary diversity, suggesting that fixing an unhealthy diet can enhance late‐life cognitive function.…”

“…Second,sex-related differences in the diet-cognition relationship might stem from distinct impacts on cognitive function in late life rather than variations in consumed foods [47]. Female cognition could be more influenced by shifts in the Dietary Diversity Score (DDS) [48]. Third, higher education levels often denote cognitive reserve, offsetting the impact of brain damage on cognition [49].…”

The Mediating Role of Psychological Balance on the Effects of Dietary Behavior on Cognitive Impairment in Chinese Elderly

“…Additionally, during long-term follow-up, they discovered that a higher DDS may slow the rate of cognitive deterioration. Song et al [ 58 ] provided more context for these findings by demonstrating that regardless of the baseline DDS, maintaining a high DDS or enhancing the DDS could reduce the risk of cognitive impairment. Consistent with previous studies, our data indicate that DDS ≤2 subjects were more likely to experience cognitive impairment.…”