High precision plasma Aβ42/Aβ40 ratio detects early amyloid deposition in non‐demented elderly adults

Plasma Aβ42/Aβ40 ratio measured by an immunoprecipitation and liquid chromatography–mass spectrometry assay showed high accordance with amyloid PET. However, it is still unclear about the risk factors related to plasma Aβ42/Aβ40, whether it can detect Aβ pathology earlier than Aβ PET, and how it relates to tau deposition, neurodegeneration and cognitive decline. In this study, we aim to investigate: 1) the risk factors related to plasma Aβ42/Aβ40; 2) the concordance and discordance of plasma Aβ42/Aβ40 and Aβ PET, and their associations with tau deposition at follow‐up and perspective changes of Aβ PET, neurodegeneration and cognition in cognitively unimpaired (CU) and mild cognitive impairment (MCI) elderly adults.