Supplementary Data to: Mediterranean diet, Alzheimer's disease biomarkers and brain atrophy in old age

<p><b>Objective:</b> To determine if following a Mediterranean-like diet (MeDi) relates to cognitive functions and <i>in vivo</i> biomarkers for Alzheimer's disease (AD), we analyzed cross-sectional data from the German Longitudinal Cognitive Impairment and Dementia Study</p> <p><b>Method:</b> The sample (n=512, mean age: 69.5±5<span>.9 years) </span><span><span>included 169 cognitively normal participants and subjects at higher AD risk (53 AD relatives, 209 SCD and 81 MCI).</span></span><span> We </span>defined MeDi adherence based on the Food Frequency Questionnaire. Brain volume outcomes were generated via voxel-based morphometry on T1-MRI and cognitive performance with an extensive neuropsychological battery. AD-related biomarkers (Aβ42/40 ratio, pTau181) in cerebrospinal fluid were assessed in n=226 individuals. We analyzed the associations between MeDi and the outcomes with linear regression models controlling for several covariates.  Additionally, we applied hypothesis-driven mediation and moderation analysis.  </p> <p><b>Results:</b> Higher MeDi adherence related to larger mediotemporal gray matter volume (p&lt;0.05 FWE corrected), better memory (β±SE = 0.03 ± 0.02; p=0.038), and less amyloid (Aβ42/40 ratio, β±SE = 0.003 ± 0.001; p=0.008) and pTau181 pathology (β±SE = -1.96±0.68; p=0.004). Results were consistent correcting for ApoE- ε4 status. Mediotemporal volume mediated the association between MeDi and memory (40% indirect mediation).  Finally, MeDi favorably moderated the associations between Aβ42/40 ratio, pTau181 and mediotemporal atrophy.  </p> <p><b>Conclusion:</b> Our findings corroborate the view of MeDi as a protective factor against memory decline and mediotemporal atrophy. Importantly, they suggest that these associations might be explained by a decrease of amyloidosis and tau-pathology. Longitudinal and dietary intervention studies should further examine this conjecture and its treatment implications.</p>