UC Irvine

The Mediterranean diet (MedDiet) has been linked with preservation of brain structures. Brain structural changes associated with cognitive impairment may occur during midlife, and timing of exposure may be critical. This study aims to examine the association of cumulative average MedDiet score from early through middle adulthood, and MedDiet scores at individual timepoints in relation to the midlife MRI brain measures. This study will also assess statistical mediation of brain measures on the association between cumulative average MedDiet score adherence and four cognitive domains: executive function, global cognition, processing speed, and verbal memory. 515 participants of the Coronary Artery Risk Development in Young Adults (CARDIA) study were included. Cumulative average MedDiet scores were calculated by averaging scores from baseline, year 7, and year 20 (mean age 25, 32, and 45, respectively). MRI brain scans were obtained at year 25 (mean age 50). General linear models adjusted for demographic variables, lifestyle factors, and vascular and metabolic comorbidities were used to examine all exposure-outcome relationships. Cumulative average MedDiet scores measured in tertiles were not associated with brain volumes. MedDiet scores examined separately at years 0, 7, and 20 were not associated with midlife brain measures. Higher cumulative average MedDiet scores were associated with better executive function (β= -0.38, ptrend <0.001). Brain volumes did not statistically mediate this association. This study’s findings suggest that diet characterized by MedDiet scores were not associated with midlife brain volumes. Midlife brain volumes did not statistically mediate the association between the MedDiet and cognition.