Abstract
INTRODUCTION: Blood-based Alzheimer's disease (AD) biomarkers provide opportunities for community studies and across ethnic groups. We investigated blood biomarker concentrations in the Washington Heights-Inwood Columbia Aging Project (WHICAP), a multi-ethnic community study of aging and dementia. METHODS: We measured plasma amyloid beta (Aβ)40, Aβ42, total tau (t-tau), phosphorylated tau (p-tau)181, and p-tau217, and neurofilament light chain (NfL) in 113 autopsied participants (29% with high AD neuropathological changes) and in 300 clinically evaluated individuals (42% with clinical AD). Receiver operating characteristics were used to evaluate each biomarker. We also investigated biomarkers as predictors of incident clinical AD. RESULTS: P-tau181, p-tau217, and NfL concentrations were elevated in pathologically and clinically diagnosed AD. Decreased Aβ42/Aβ40 ratio and increased p-tau217 and p-tau181 were associated with subsequent AD diagnosis. DISCUSSION: Blood-based AD biomarker concentrations are associated with pathological and clinical diagnoses and can predict future development of clinical AD, providing evidence that they can be incorporated into multi-ethnic, community-based studies.