Lehmann S, Dumurgier J, Ayrignac X, et al. - Researchers examined the levels of Aβ1–40 applying multicenter data collected on 2,466 samples from six different cohorts in which cerebrospinal fluid was obtained under standardized protocols, centrifugation, and storage conditions. Commercially available in vitro diagnostic immunoassays were used to assess tau and p-tau (181) concentrations. They computed statistical analyses for parametric and non-parametric comparisons, linear regression, correlation, and odds ratios. The data demonstrate that an increase in the baseline level of amyloid peptides, which are correlated with an increase in p-tau (181), maybe a biological characteristic and possibly a risk factor for Alzheimer’s disease. Future trials are needed to develop a causal relationship between elevated baseline levels of Aβ40 and the development of the disease. A slight but significant age-independent increase in the levels of Aβ40 in CSF was observed in AD, regardless of the analysis method used and the cohorts. Between the levels of Aβ1–40 and p-tau (181) in CSF, a strong positive correlation was also seen, especially in controls.