Independent associations of phosphorylated tau181 and neurofilament light with cognitive outcomes in the Health and Aging Brain Study-Health Disparities (HABS-HD).

Among non-Hispanic White participants, both higher p-tau181 and higher NfL were independently associated with poorer performance across all four cognitive domains.

• Cognitive domains assessed were memory, executive function, processing speed, and language.
• Models included both p-tau181 and NfL simultaneously to assess independent associations.
• Covariates included age, sex, education, and apolipoprotein ε4 carriership.
• NHW participants comprised 38.4% of the total sample (n=3023 community-dwelling older adults).

In non-Hispanic Black participants, p-tau181 was associated with memory, executive function, and processing speed, but showed attenuated associations for language.

• NHB participants comprised 22.6% of the total sample.
• Associations for executive function and processing speed were described as similar to those observed in NHW participants.
• The language association was specifically described as 'attenuated' compared to NHW participants.
• NfL associations in NHB participants were not highlighted as notably different from NHW for these domains in the abstract.

In Hispanic participants, p-tau181 was associated with memory and processing speed but was nonsignificant for executive function and language, and NfL showed significant but attenuated associations across all domains.

• Hispanic participants comprised 38.9% of the total sample.
• NfL associations were present across all four domains in Hispanic participants but described as 'attenuated' relative to NHW participants.
• P-tau181 showed a more restricted pattern of significant associations in Hispanic participants compared to NHW participants.
• Biomarker × racial/ethnic interactions were evaluated to assess whether associations differed across groups.

Higher p-tau181 and NfL jointly associated with slower processing speed only in NHW and NHB participants, not in Hispanic participants.

• A p-tau181 × NfL interaction was tested within each racial/ethnic group.
• The joint association was specific to processing speed and was not observed for memory, executive function, or language.
• This interaction was absent in Hispanic participants.
• The analysis was conducted in a sample of 3023 community-dwelling older adults.

The study analyzed 3023 community-dwelling older adults from the Health and Aging Brain Study-Health Disparities (HABS-HD) across three racial/ethnic groups.

• The sample comprised 38.4% non-Hispanic White, 22.6% non-Hispanic Black, and 38.9% Hispanic participants.
• Plasma biomarkers measured were phosphorylated tau181 (p-tau181) and neurofilament light (NfL).
• Linear regression models were used to test associations between plasma biomarkers and cognitive domains.
• Models adjusted for age, sex, education, and apolipoprotein ε4 carriership.