BACKGROUND: Blood-based biomarkers hold promise as a minimally invasive tool for identifying early signs of Alzheimer's disease pathology and neurodegeneration. We investigated associations between plasma biomarkers of amyloid-beta, tau, neuroaxonal injury, and glial activation with cognitive performance among community-dwelling Hispanic/Latino adults in the United States.

METHODS: We analyzed cross-sectional data from 5730 adults aged 50 years and older (unweighted; mean [SD], 63.5 [8.2] years) in the Study of Latinos-Investigation of Neurocognitive Aging (SOL-INCA; 2016-2018). Plasma concentrations of amyloid-beta (Aβ), phosphorylated tau-181 (pTau-181), neurofilament light chain (NfL), and glial fibrillary acidic protein (GFAP) were quantified (Quanterix Simoa HD-X) and log-transformed (ln). Cognitive performance was assessed across domain-specific scores (learning, memory, verbal fluency, and executive functioning/processing speed) used to calculate global cognitive performance. Survey-weighted linear regression models were used to examine associations between plasma biomarkers and cognitive performance, adjusting for sociodemographic, cardiometabolic, kidney, and APOE ε4 covariates.

RESULTS: Here we show higher ln(pTau-181) and ln(NfL) are associated with lower global cognitive performance (b = -0.06; 95%CI = [-0.12;-0.01]; p = 0.022; b = -0.07; 95%CI = [-0.12;-0.02]; p = 0.005). Lower ln(Aβ) is associated with poorer verbal fluency, higher ln(pTau-181) is associated with poorer learning and memory, and higher ln(NfL) is associated with learning and executive functioning/processing speed. We find ln(GFAP) is not significantly associated with cognitive performance.

CONCLUSIONS: Plasma biomarkers related to Alzheimer's disease pathophysiology and broader neurodegenerative processes are associated with cognitive performance among Hispanic/Latino adults. These findings highlight the potential utility of blood-based biomarkers for identifying early cognitive vulnerability in this population.