Associations Between Blood‐based Biomarkers and Other Outcomes Related to Alzheimer’s Disease

Background Blood‐based biomarkers (BBM) have shown promising potential in diagnosis and prognosis of patients affected by Alzheimer’s disease (AD) pathology. This observational study analyzed the cross‐sectional relation between BBMs and disease relevant outcomes (e.g., cognition, imaging modalities). Method The study sample comprised individuals with subjective cognitive decline (N = 35), mild cognitive impairment (N = 30), dementia due to suspected AD (N = 27) and healthy controls (N = 35). Data for the following measures were assessed: 1) AD‐related BBMs measured in plasma on Simoa: amyloid beta ratio 42/40 (Ab42/40), tau phosphorylated at threonine‐181 (p‐Tau 181), glial fibrilic acid protein (GFAP), and neurofilament light chain (NfL), 2) several cognitive parameters, 3) structural volumes, functional connectivity and brain metabolite concentrations measured by 7T magnetic resonance imaging (MRI) and spectroscopy (MRS), and 4) concentrations of general blood count. Linear mixed models were used to assess associations between the AD‐related BBMs (1) and the other measures (2 to 4). Result While none of the associations between Ab42/40 and the AD‐related outcome measures reached significance (p > 0.05), higher concentrations of p‐Tau 181, GFAP and NfL were associated with lower values for MMSE, memory and executive function and parietal cortical thickness, as well as higher concentrations of MRS Myo‐inositol and blood creatinine (figure 1). Additionally, GFAP and NfL were associated with lower MRS N‐Acetylaspartic acid (NAA), and GFAP was associated with smaller hippocampus volume. Beta‐coefficients and p‐values for all associations are provided in table 1. Conclusion Unlike Ab42/40, abnormal concentrations of p‐Tau 181, GFAP and NfL showed strong and robust associations to other AD‐related outcome measures making them a better target for screening, diagnosis and possibly prognosis for individuals with AD.