Alzheimer's disease plasma biomarkers are associated with cognitive performance among Hispanic/Latino adults.

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 (Aβ42/40), 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 (bpTau-181 = -0.06; 95%CI = [-0.12;-0.01]; p = 0.022; bNfL = -0.07; 95%CI = [-0.12;-0.02]; p = 0.005). Lower ln(Aβ42/40) 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. This study looked at how certain substances in the blood, called biomarkers, are linked to thinking and memory abilities in Hispanic/Latino adults aged 50 and older in the United States. These biomarkers can reflect changes in the brain related to Alzheimer’s disease and other conditions that affect cognition. Researchers tested blood samples from over 5700 adults aged 50 and older and compared the results with their performance on memory and thinking tests. They found that people with higher levels of certain biomarkers had lower cognitive scores. This research helps us understand how blood tests might one day help detect early brain changes in diverse communities. It also highlights the importance of including underrepresented populations in aging and brain health research.