Biofluid biomarkers in an ethnoracially diverse population and their association with AD

Abstract

AbstractBackgroundPlasma‐based biomarkers of Alzheimer’s disease are cost‐effective, minimally invasive and highly scalable tools to aid in clinical practice and trials. There remain significant gaps in our understanding of the factors that influence their levels. The majority of fluid biomarker research has been conducted in clinical settings using CSF biomarkers with non‐Hispanic Whites. Although Hispanic and African American communities have higher rates of dementia, there is limited research on blood‐based biomarkers of AD in these communities. The current study of a sample of Mexican Americans, African Americans and Non‐Hispanic Whites investigated the performance of plasma biomarker across the three largest ethnic/racial groups in the US to assess the impact of ethnicity/race on the level of the plasma biomarkers of Aβ40, Aβ42, total tau, ptau 181 and NfL.MethodParticipants were 2200 community dwelling older adults (850 Mexican Americans (MA); 850 Non‐Hispanic Whites (NHW) and 500 African Americans (AA) drawn from The Health & Aging Brain Study – Health Disparities (HABS‐HD) study. Cognitive diagnoses were assigned using an algorithm verified by consensus review. Samples were assayed using Simoa technology. Levels of each biomarker were compared for the three ethnoracial groups across cognitive diagnoses.ResultsSignificant differences were found across the groups at each level of cognitive impairment. For those with normal cognition AA had significantly lower levels of each of the biomarkers and NHW had higher levels of Aβ40, Aβ42 and NFL. MA had the highest level of t tau and p tau 181. MCI group NHW had the highest levels on all the biomarkers and AA had the lowest. NHW and MA has higher levels of Aβ40, Aβ42, total tau, ptau 181 compared to AA. NHW levels of NfL were the highest and MA and AA did not differ. For dementia there was no difference between the groups for Aβ42. NHW had significantly higher levels of Aβ40, t tau, ptau 181 and NfL than AA.ConclusionFindings support the importance of considering ethnoracial background in the clinical use of blood‐based biomarkers and the difficulty of establishing universal cutting points for these biomarkers in the diagnostic process.