Dietary patterns and risk of Alzheimer's disease and related dementias across 5 racial and ethnic groups in the Multiethnic Cohort Study.

BACKGROUND

Healthier dietary patterns have been linked to a lower risk of dementia, but data from diverse racial and ethnic populations are limited, particularly to support dietary improvement in older adults.

OBJECTIVES

We examined dietary patterns in relation to late-onset Alzheimer's disease and related dementia (ADRD) risk across 5 racial and ethnic groups in the Multiethnic Cohort Study.

METHODS

Participants were scored for 4 predefined dietary pattern indices based on their food frequency questionnaire responses at baseline (45-75 y) and at a 10-y follow-up: the alternate Mediterranean diet (aMED), the Dietary Approaches to Stop Hypertension (DASH), the Healthy Eating Index-2015 (HEI-2015), and the Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet. Associations between dietary patterns and ADRD were examined using Cox proportional hazards models to estimate hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

Among 92,849 participants with 21,478 cases, higher baseline scores of the 4 dietary patterns were associated with 4%‒9% lower ADRD risk (for aMED, HR 0.91, 95% CI: 0.87, 0.95; for DASH, HR 0.96, 95% CI: 0.92, 1.01; for HEI-2015, HR 0.94, 95% CI: 0.90, 0.98; for MIND, HR 0.91, 95% CI: 0.87, 0.96) over the follow-up, with stronger associations observed in African American, Latino, and White participants than in Japanese American and Native Hawaiian participants. Dietary improvement over 10 y was associated with 11%‒25% lower risk across the 4 indices in a subset of 45,065 participants with 8360 cases, with similar racial and ethnic differences as observed for baseline diet, but consistently for younger (<60 y at baseline) and older age groups.

CONCLUSIONS

Healthy dietary patterns in mid- to late-life and improvement in older age were associated with a reduced risk of ADRD in a diverse population. The racial and ethnic heterogeneity in the relationships observed warrants further study.