Associations of Plasma Tau with Amyloid and Tau PET: Results from the Community-Based Framingham Heart Study.

Associations of plasma total tau levels with future risk of AD have been described. To examine the extent to which plasma tau reflects underlying AD brain pathology in cognitively healthy individuals. We examined cross-sectional associations of plasma total tau with 11C-Pittsburgh Compound-B (PiB)-PET and 18F-Flortaucipir (FTP)-PET in middle-aged participants at the community-based Framingham Heart Study. Our final sample included 425 participants (mean age 57.6± 9.9, 50% F). Plasma total tau levels were positively associated with amyloid-β deposition in the precuneus region (β±SE, 0.11±0.05; p = 0.025). A positive association between plasma total tau and tau PET in the rhinal cortex was suggested in participants with higher amyloid-PET burden and in APOEɛ4 carriers. Our study highlights that plasma total tau is a marker of amyloid deposition as early as in middle-age.