Association of Mediterranean Diet With Cognitive Decline Among Diverse Hispanic or Latino Adults From the Hispanic Community Health Study/Study of Latinos

IMPORTANCE: The Mediterranean diet may reduce the burden of Alzheimer disease and other associated dementias in Hispanic or Latino people. OBJECTIVE: To investigate the association of a Mediterranean diet with cognitive performance among community-dwelling Hispanic or Latino adults. DESIGN, SETTING, AND PARTICIPANTS: This cohort study analyzed data from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL) and the Study of Latinos–Investigation of Neurocognitive Aging (SOL–INCA), an HCHS/SOL ancillary study. Cognition tests were administered in the HCHS/SOL from March 2008 to June 2011 (visit 1) and in the SOL–INCA from October 2015 to March 2018 (visit 2). Participants included in the present study had completed a diet assessment at visit 1 and neurocognitive evaluations at visits 1 and 2. Data were analyzed from September 2021 to May 2022. EXPOSURES: Mediterranean diet adherence was ascertained using the Mediterranean diet score (MDS) and was categorized as low (MDS: 0-4 points), moderate (MDS: 5-6 points), or high (MDS: 7-9 points). The mean of two 24-hour dietary recalls was used to calculate the MDS. MAIN OUTCOMES AND MEASURES: Cognitive change between visits 1 and 2 was calculated by subtracting the cognitive score at visit 2 from the cognitive score at visit 1 and adjusting by the time elapsed between visits and cognitive score at visit 1. Neurocognitive tests administered were Brief Spanish-English Verbal Learning Test (B-SEVLT) Sum, B-SEVLT Recall, word fluency, and Digit Symbol Substitution Test (DSST). Results of each test were z score–transformed and the means were averaged to create a global cognition score. Complex sample linear regression analysis was used to ascertain the association between MDS and neurocognitive performance at each visit and neurocognitive change. RESULTS: A total of 6321 participants (mean [SE] age, 56.1 [0.18] years at visit 1; n = 4077 women [57.8%]) were included. Mediterranean diet adherence weighted frequencies were 35.8% (n = 2112 of 6321) for the low adherence group, 45.4% (n = 2795) for the moderate adherence group, and 18.8% (n = 1414) for the high adherence group. In the fully adjusted model, z score–transformed cognitive scores at visit 1 in the high vs low adherence groups were higher for B-SEVLT Sum (β = 0.11; 95% CI, 0.02-0.20), B-SEVLT Recall (β = 0.16; 95% CI, 0.07-0.25), and global cognition (β = 0.10; 95% CI, 0.04-0.16) tests. In the mean follow-up time of 7 years, cognitive change in the high vs low adherence groups was less pronounced for B-SEVLT Sum (β = 0.12; 95% CI, 0.05-0.20) and B-SEVLT Recall (β = 0.14; 95% CI, 0.05-0.23), but not for word fluency, DSST score, or global cognition score. CONCLUSIONS AND RELEVANCE: Results of this cohort study suggested that high adherence to a Mediterranean diet was associated with better cognitive performance and decreased 7-year learning and memory decline among middle-aged and older Hispanic or Latino adults. Culturally tailored Mediterranean diet may reduce the risk of cognitive decline and Alzheimer disease in this population.