Plasma Alzheimer's biomarkers and brain amyloid in Hispanic and non‐Hispanic older adults

Abstract

AbstractINTRODUCTIONAlzheimer's disease studies often lack ethnic diversity.METHODSWe evaluated associations between plasma biomarkers commonly studied in Alzheimer's (p‐tau181, GFAP, and NfL), clinical diagnosis (clinically normal, amnestic MCI, amnestic dementia, or non‐amnestic MCI/dementia), and Aβ‐PET in Hispanic and non‐Hispanic older adults. Hispanics were predominantly of Cuban or South American ancestry.RESULTSThree‐hundred seventy nine participants underwent blood draw (71.9 ± 7.8 years old, 60.2% female, 57% Hispanic of which 88% were Cuban or South American) and 240 completed Aβ‐PET. P‐tau181 was higher in amnestic MCI (p = 0.004, d = 0.53) and dementia (p < 0.001, d = 0.97) than in clinically normal participants and discriminated Aβ‐PET[+] and Aβ‐PET[‐] (AUC = 0.86). P‐tau181 outperformed GFAP and NfL. There were no significant interactions with ethnicity. Among amnestic MCI, Hispanics had lower odds of elevated p‐tau181 than non‐Hispanic (OR = 0.41, p = 0.006).DISCUSSIONPlasma p‐tau181 informs etiological diagnosis of cognitively impaired Hispanic and non‐Hispanic older adults. Hispanic ethnicity may relate to greater likelihood of non‐Alzheimer's contributions to memory loss.Highlights Alzheimer's biomarkers were measured in Hispanic and non‐Hispanic older adults. Plasma p‐tau181 related to amnestic cognitive decline and brain amyloid burden. AD biomarker associations did not differ between Hispanic and non‐Hispanic ethnicity. Hispanic individuals may be more likely to have non‐Alzheimer causes of memory loss.