Plasma‐based biomarkers of Alzheimer’s Disease in a multi‐ethnic population: A Cross‐Sectional analysis from the WHICAP Study

Abstract

AbstractBackgroundBlood‐based biomarkers have the unique potential to make diagnoses along the Alzheimer’s Disease (AD) continuum. The value of these plasma‐based biomarkers in AD among different race and ethnicity, sex, and genetic status groups needs to be evaluated.MethodThe study included 603 participants of the Washington Heights Inwood Columbia Aging Project, a community‐based cohort study. We measured six AD biomarkers, including phosphorylated Tau‐181 (PTau181), total Tau, Amyloid Beta (Aβ) 40, Aβ42, Glial Fibrillary Acid Protein (GFAP), and Neurofilament Light Chain (NfL). We compared the biomarker levels among 95 individuals clinically diagnosed with AD, 167 individuals with Mild Cognitive Impairment (MCI), and 341 cognitively unimpaired individuals using linear regression models, adjusting for age, sex, race and ethnicity, years of education, APOE ɛ4 status, and sample storage time. We further examined whether the association between biomarkers and clinical diagnosis differed by racial and ethnic groups, sex, and APOE ɛ4 status.ResultThe participants were on average 80.23 (SD = 6.77) years old. Participants self‐identified as non‐Hispanic White (24.03%), non‐Hispanic Black (24.70%), or Hispanic (51.21%), with 414 women (68.66%). AD participants had elevated total tau levels (β = 0.303, p = 0.029), NfL (β = 0.472, p <0.001), and GFAP (β = 0.467, p < 0.001) compared to cognitively unimpaired participants. Individuals with MCI also had higher levels of total tau (β = 0.258, p = 0.016), NfL (β = 0.234, p = 0.035), and GFAP (β = 0.248, p = 0.02) than controls. Stratified analyses showed that men with MCI had higher NfL levels than cognitively unimpaired individuals (β = 0.123, p = 0.008). In women, there were no observable differences in NfL levels between individuals with MCI and controls (β = 0.014, p = 0.669). Among APOE e4 carriers, individuals with MCI had higher levels of NfL than unimpaired controls (β = 0.157, p = 0.006). This was not observed in APOE e4 non‐carriers (β = 0.025, p = 0.397).ConclusionConsistent with the literature, we found plasma AD biomarkers including total tau, NfL, and GFAP were higher in MCI and AD compared with cognitively unimpaired individuals. Among men and APOE e4 carriers, we found higher NfL levels in MCI individuals than in cognitively unimpaired individuals.