Dietary patterns and transition from normal cognition to mild cognitive impairment and its reversion: A longitudinal study of older adults

Background

The reversion from mild cognitive impairment (MCI) to normal cognition (NC) has received less attention than the progression to dementia. We aimed to estimate the MCI-to-NC reversion rate and examine dietary patterns associated with the cognitive transition among older adults.

Methods

Longitudinal data from 11,211 adults aged 65 years and older were analyzed. Four dietary patterns including plant-based diet index (PDI), simplified healthy eating index (SHEI), dietary diversity score (DDS), and the Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) were assessed with the food frequency questionnaire. Cognitive function was quantified with the Mini-Mental State Examination. The multi-state Markov models were applied to estimate associations between each dietary pattern and transition of cognitive status with four states: NC, MCI, dementia, and death.

Results

Participants (mean [SD] age, 85.80 [11.13] years; 6211 women [55.40 %] and 5000 men [44.60 %]) were followed over a mean time of 4.76 (SD = 3.14) years. The rate of reversion from MCI to NC was 9.4 %. Hazard ratios (HRs, 95 % confidence interval [CI]) for the progression from NC to MCI were 0.87 (0.77–0.97), 0.81 (0.73–0.91), 0.95 (0.92–0.99), and 0.95 (0.92–0.99) for dietary patterns of healthful PDI (hPDI), SHEI, DDS, and MIND, respectively. Besides, a better adherence to hPDI (HR = 1.21, 95 % CI = 1.03 to 1.43) and SHEI (HR = 1.20, 95 % CI = 1.02 to 1.41) was associated with increased likelihoods to revert from MCI to NC.

Conclusions

Dietary patterns of hPDI, SHEI, DDS, and MIND were linked to decreased risks of NC-to-MCI progression, and hPDI and SHEI were associated with higher likelihoods of MCI-to-NC reversion in older adults. Interventional studies with dietary patterns were warranted to confirm our findings.