Acculturation in Context and Brain Health in Older Latino Adults: A Diffusion Tensor Imaging Study

Article type: Research Article

Authors: Fleischman, Debra A.^{a; b; c; *} | Arfanakis, Konstantinos^{a; d; e} | Zhang, Shengwei^a | Leurgans, Sue E.^{a; b} | Barnes, Lisa L.^{a; b; c} | Bennett, David A.^{a; b} | Marquez, David X.^{a; f} | Lamar, Melissa^{a; c}

Affiliations: [a] Rush Alzheimer’s Disease Center, Rush University Medical Center, Chicago, IL, USA | [b] Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, USA | [c] Department of Psychiatry and Behavioral Sciences, Rush University Medical Center, Chicago, IL, USA | [d] Department of Diagnostic Radiology and Nuclear Medicine, Rush University Medical Center, Chicago, IL, USA | [e] Department of Biomedical Engineering, Illinois Institute of Technology, Chicago, IL, USA | [f] Department of Kinesiology and Nutrition, University of Illinois Chicago, Chicago, IL, USA

Correspondence: [*] Correspondence to: Debra A. Fleischman, PhD, Rush Alzheimer’s Disease Center, Rush University Medical Center, 1725 W. Harrison, Suite 1000, Chicago, IL 60612, USA. Tel.: +1 312 942 2286; Fax: +1 312 942 2297; E-mail: [email protected].

Abstract: Background:Latinos are at higher risk of developing mild cognitive impairment (MCI) and Alzheimer’s disease than non-Latino Whites. Acculturation factors may influence this risk, yet there are few studies that have examined associations of acculturation, particularly in the context of socioenvironmental and familial factors, and brain health in older Latinos. Objective:To examine potential associations between acculturation in context and brain health in older Latinos. Methods:Using three previously established composites of acculturation-in-context, (acculturation-related: nativity status, language preference, acculturation scores; contextually-related socioenvironmental: perceived discrimination, loneliness/social isolation, social network size; and familism), and diffusion-tensor imaging (DTI), associations with white matter structural integrity were examined in 92 Latino adults without dementia participating in one of three epidemiological studies of aging. Linear regression models were used to test associations with DTI-derived metrics (fractional anisotropy, FA; trace) as separate outcomes and acculturation composite scores as individual predictors, while adjusting for age, sex, education, scanner, and white matter hyperintensities (voxelwise and total volumes normalized by intracranial volume). Results:Higher scores on the socioenvironmental composite were associated with lower FA in two clusters of left-hemisphere connections. Cluster 1 was dominated by both short association pathways connecting frontal regions and projection pathways connecting frontal regions with the thalamus. Cluster 2 was dominated by long association pathways connecting parietal, frontal, and temporal regions. Conclusions:This study of older Latino adults demonstrated an association between reduced brain white matter integrity and contextually related socioenvironmental experiences known to increase risk of MCI and Alzheimer’s disease.

Keywords: Acculturation, Alzheimer’s disease, brain structure, diffusion-tensor imaging, Hispanic, Latino, social determinants of health

DOI: 10.3233/JAD-230491

Journal: Journal of Alzheimer's Disease, vol. 95, no. 4, pp. 1585-1595, 2023