Abstract
BACKGROUND: Although blood-based biomarkers can be used to detect early Alzheimer's disease (AD), population differences affect their clinical value in early diagnosis of the disease spectrum. AIMS: To examine the potential of plasma biomarkers to detect different stages along the AD continuum in a Chinese population. METHODS: We enrolled 113 adults from the Shenzhen community (53 cognitively unimpaired [CU], 45 with mild cognitive impairment [MCI], and 15 with AD). We used the single-molecule array technique to detect the levels of glial fibrillary acidic protein (GFAP), neurofilament light (NfL), and phosphorylated-tau181 (p-tau181), and performed APOE genotyping. We assessed the association between plasma biomarkers and cognitive scores, and used receiver operating characteristic curves to measure performance for early AD diagnosis. RESULTS: The plasma GFAP, NfL, and p-tau181 levels increased significantly in AD and were slightly higher in MCI than in CU (GFAP p = 0.811, NfL p = 0.909, p-tau181 p = 0.696). The plasma GFAP and p-tau181 levels negatively correlated with cognitive scores. Blood markers demonstrated higher performance in identifying AD than CU or MCI. Plasma p-tau181 displayed the highest diagnostic value for AD. Predictions of cognitive impairment were more robust when blood markers were combined with clinical indicators for AD (age, sex, body mass index, years of education, and APOE ε4 carrier status). DISCUSSION: The expression of plasma GFAP, NfL, and p-tau181 increased in the AD continuum. Importantly, plasma p-tau181 could identify individuals with AD from the general population, with superior predictive performance when combined with age or sex. CONCLUSIONS: Plasma biomarkers are useful screening indicators for early AD in Chinese adults.