Emerging positron emission tomography (PET) research suggests that a higher educational level may have an impact upon the speed and spread of tau accumulation.
For the study, recently published in JAMA Neurology, researchers examined the impact of higher educational attainment (EA) upon tau accumulation in a total cohort of 887 participants drawn from datasets for the Alzheimer’s Disease Neuroimaging Initiative (ADNI), the Anti-Amyloid Treatment in Asymptomatic Alzheimer’s Disease study and the Greater-Bay-Area Healthy Aging Brain Study (GHABS). The cohort included participants with no cognitive impairment, those with mild cognitive impairment (MCI) and people with Alzheimer dementia, according to the study.
For study participants with amyloid β negative (Aβ-) PET findings, the study authors found slower tau accumulation in the right middle temporal gyrus among those with high EA in contrast to individuals with low EA.
However, the researchers also noted that the combination of amyloid β positive (Aβ+) PET findings and high EA was associated with accelerated tau and entorhinal cortex tau (EC tau)-associated accumulation in the left middle temporal gyrus in contrast to study participants with Aβ+ findings and lower EA. The study authors pointed out accelerated plasma p-tau217-associated tau accumulation in the left inferior temporal gyrus for people with high EA and Aβ+ PET findings.
“Higher EA was associated with slower tau accumulation in Aβ− individuals but faster tau accumulation in Aβ+ individuals. In Aβ+ individuals, higher EA was associated with accelerated Aβ, EC tau, and plasma p-tau217 tau accumulation, as well as greater connectivity-associated tau spread,” wrote lead study author Yue Cai, Ph.D., who is affiliated with the Institute of Neurological and Psychiatric Disorders at Shenzhen Bay Laboratory in Shenzhen Bay Laboratory in Shenzhen, China, and colleagues.
Three Key Takeaways
1. Educational attainment and tau accumulation vary by amyloid status. Higher educational attainment (EA) is associated with slower tau accumulation in amyloid-β negative (Aβ−) individuals, particularly in the right middle temporal gyrus.
2. Paradoxical effect in amyloid-positive individuals. In amyloid-β positive (Aβ+) individuals, higher EA is linked to accelerated tau accumulation, especially in the left middle and inferior temporal gyri, as well as greater connectivity-associated tau spread.
3. Implications for disease progression. These findings suggest that cognitive reserve from education may delay pathology in Aβ− individuals, but in Aβ+ individuals, brain connectivity and reserve may facilitate wider tau propagation, potentially influencing the course of Alzheimer's disease.
In comparison to study participants with low EA, the researchers also noted significantly greater connectivity-associated tau spread and late Braak stage cortices in Aβ+ individuals with high EA.
“Future studies should examine the association between EA-related factors—such as brain connectivity changes, lifestyle differences, and cognitive reserve—and longitudinal tau changes to further elucidate the mechanisms underlying accelerated EA-associated tau accumulation in Aβ+ individuals,” posited Cai and colleagues.
(Editor’s note: For related content, see “SNMMI: What Tau PET Findings May Reveal About Modifiable Factors for Alzheimer’s Disease,” “New Study Shows Impact of Tau-Positive PET in Risk Stratification for Dementia and Alzheimer’s Disease” and “A Closer Look at the New Appropriate Use Criteria for Brain PET: An Interview with Phillip Kuo, MD, Part 2.”)
In regard to study limitations, the authors acknowledged a lack of longitudinal tau PET scans in two of the three datasets utilized in the study and conceded that multiple comparison corrections thwarted consideration of regional results for 200 regions of interest (ROIs).
