Science

Puja Agarwal, PhD, Sue E. Leurgans, PhD, Sonal Agrawal, PhD, Neelum T. Aggarwal, MD, Laurel J. Cherian, MD, Bryan D. James, PhD, Klodian Dhana, MD, PhD, Lisa L. Barnes, PhD, David A. Bennett, MD, and
Julie A. Schneider, MD

Background and Objectives
Diet may reduce Alzheimer dementia risk and slow cognitive decline, but the understanding of the relevant neuropathologic mechanisms remains limited. The association of dietary patterns with Alzheimer disease (AD) pathology has been suggested using neuroimaging biomarkers. This study examined the association of Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) and Mediterranean dietary patterns with β-amyloid load, phosphorylated tau tangles, and global AD pathology in postmortem brain tissue of older adults.

Methods
Autopsied participants of the Rush Memory and Aging Project with complete dietary in- formation (collected through a validated food frequency questionnaire) and AD pathology data (β-amyloid load, phosphorylated tau tangles, and global AD pathology [summarized neurofi- brillary tangles and neuritic and diffuse plaques]) were included in this study. Linear regression models controlled for age at death, sex, education, APOE-«4 status, and total calories were used to investigate the dietary patterns (MIND and Mediterranean diets) and dietary components associated with AD pathology. Further effect modification was tested for APOE-«4 status and sex.

Results
Among our study participants (N = 581, age at death: 91.0 ± 6.3 years; mean age at first dietary assessment: 84.2 ± 5.8 years; 73% female; 6.8 ± 3.9 years of follow-up), dietary patterns were associated with lower global AD pathology (MIND: β = −0.022, p = 0.034, standardized β = −2.0; Mediterranean: β = −0.007, p = 0.039, standardized β = −2.3) and specifically less β-amyloid load (MIND: β = −0.068, p = 0.050, standardized β = −2.0; Mediterranean: β = −0.040, p = 0.004, standardized β = −2.9). The findings persisted when further adjusted for physical activity, smoking, and vascular disease burden. The associations were also retained when participants with mild cognitive impairment or dementia at the baseline dietary assessment were excluded. Those in the highest tertile of green leafy vegetables intake had less global AD pathology when compared with those in the lowest tertile (tertile 3 vs tertile 1: β = −0.115, p = 0.0038).