The Link between APOE4 Presence and Neuropsychological Test Performance among Mexican Americans and Non-Hispanic Whites of the Multiethnic Health & Aging Brain Study - Health Disparities Cohort

Introduction: The APOEϵ4 allele is the single strongest genetic risk for late-onset Alzheimer's disease (AD). Prior work demonstrates that not only the APOEϵ4 allele varies by race/ethnicity but also the risk for AD and cognitive impairment conveyed by the APOEϵ4 allele varies by the racial/ethnic group as well as genetic ancestry. Here, we sought to examine the link between the APOEϵ4 and neuropsychological functioning among Mexican Americans (MAs). Methods: Data were examined from 1,633 (852 MAs and 781 non-Hispanic Whites [NHWs]) participants of the Health & Aging Brain Study - Health Disparities (HABS-HD) and were enrolled with all requisite data to be included into the current analyses. Results: The frequency of both ϵ4 and ϵ2 alleles was significantly lower among MAs as compared to NHWs. Among MAs, APOEϵ4 allele presence was associated specifically with poorer immediate and delayed memory (Wechsler Memory Scale - Third Edition [WMS-III] Logical Memory and Spanish-English Verbal Learning Test [SEVLT]). Among NHWs, APOEϵ4 allele presence was associated with poorer immediate and delayed memory as well as worse executive functioning (Trials B) and verbal fluency (Animal naming). Discussion/Conclusion: The APOEϵ4 allele was associated with poorer cognition across multiple domains among NHWs; however, allele presence was specifically associated with poorer memory performance among MAs. When combined with prior work, the current findings demonstrate that the risk factors associated with cognitive dysfunction differ among MAs as compared to NHWs and require additional investigation.