Continued Efforts to Identify Blood Biomarkers for Early Alzheimer's Disease
While the first blood-based assays are entering use for the early detection and diagnosis of Alzheimer's disease, they remain expensive and are so far employed for only a limited number of patients. More work is needed to identify associations between circulating factors and disease progression, in order to produce better combinations of biomarker assays that can be more widely deployed at a lower cost. Thus expect to see more research along the lines of the paper noted here, in which the association between loss of cognitive function and circulating levels of some of the better known biomarkers are more carefully studied in a given population.
Subjective cognitive decline (SCD) may be an early indicator of Alzheimer disease and related dementias (ADRD), yet its association with plasma biomarkers remains unclear among middle-aged and older adults. his cross-sectional study used survey-weighted data from the Study of Latinos-Investigation of Neurocognitive Aging, an ancillary study of the Hispanic Community Health Study/Study of Latinos. Participants were aged 50 to 86 years and resided in 4 major US cities. Data were collected from 2016 to 2018 and analyzed between December 2024 and June 2025.
Plasma biomarkers included amyloid-beta (Aβ42/Aβ40), phosphorylated tau-181 (ptau-181), neurofilament light chain (NfL), and glial fibrillary acidic protein (GFAP). SCD was assessed using the short-form Everyday Cognition Scale (ECog-12), evaluating global-, executive-, and memory-related SCD, and a single-item cognitive concerns question.
Among 5,712 adults (mean age 63.47 years), higher ln(ptau-181) was associated with ECog-12 memory (unstandardized β = 0.088). Higher ln(NfL) levels were associated with greater ECog-12 global (unstandardized β = 0.169), executive (unstandardized β = 0.182), and memory (unstandardized β = 0.156) domains. Higher ln(GFAP) levels were associated with greater ECog-12 global (unstandardized β = 0.109) and executive (unstandardized β = 0.121) domains. Ln(Aβ42/40) was not associated with SCD domains. Cognitive concerns significantly modified the associations between ln(NfL) and ECog-12 domains, with more pronounced associations among those reporting cognitive concerns. These findings underscore the potential utility of p-tau181, NfL, and GFAP, but not Aβ42/40, in early ADRD detection strategies.