2026 American Academy of Neurology Abstract Website

Objective:

To evaluate, in cognitively normal adults, the associations between five platelet indices—plateletcrit (PCT), platelet count (PLT), mean platelet volume (MPV), platelet distribution width (PDW), and platelet large cell ratio (PLCR)—and CSF AD biomarkers (Aβ42, Aβ42/Aβ40, P-tau/Aβ42, T-tau/Aβ42), and to examine effect modification by age and the robustness of findings.

Background:

Prior studies suggest that certain platelet indices correlate with cognitive impairment, but their relationships with cerebrospinal fluid (CSF) Alzheimer’s disease (AD) biomarkers remain unclear

Design/Methods:

We included 1,047 cognitively normal participants from the CABLE study (mean age 58.33 years; 41.5% female; mean education 9.58 years). Multiple linear regression models assessed associations of platelet indices with CSF biomarkers, adjusting for age, sex, education, and APOE ε4 status. Interaction, stratified (mid-life vs late-life), and sensitivity analyses were conducted.

Results:

Higher PCT was significantly associated with higher CSF P-tau/Aβ42 (β=0.102, P=0.008) and T-tau/Aβ42 (β=0.102, P=0.008), and with lower CSF Aβ42 (β=−0.089, P=0.018) and Aβ42/Aβ40 (β=−0.093, P=0.018). The other four indices (PLT, MPV, PDW, PLCR) showed moderate correlations with CSF AD biomarkers. Age modified associations of PCT and PLT with Aβ42: effects were stronger and significant in the late-life group but non-significant in the mid-life group. Sensitivity analyses supported robustness.

Conclusions:

Platelet indices—particularly PCT—show potential associations with CSF AD pathology markers in cognitively intact adults. Further studies, including longitudinal and causal analyses, are needed to validate and elucidate underlying mechanisms and clinical implications.