Background: Despite the effect of education and APOE ε4 allele on amyloid-beta (Aβ)
retention and memory, previous studies have not dealt with an interaction between two factors on Aβ
deposition and memory function in the course of Alzheimer’s disease (AD).
Objective: To evaluate education by APOE ε4 allele interactions for Aβ retention and neuropsychological
test scores in cognitively normal older adults without Aβ deposition [CN(Aβ-), n=45] and
Alzheimer’s disease patients with Aβ retention [AD(Aβ+), n=33].
Methods: Multiple regression analyses (adjusted for age, gender) were conducted to examine the
effects of education, APOE ε4 allele, and the interaction between the two factors on global, regional
Aβ load quantified using [18F]flutemetamol standardized uptake value ratio with the pons as a reference
region, and on neuropsychological test scores in each group.
Results: The interaction between education and APOE ε4 allele had an effect on amyloid load in parietal
lobes (uncorrected p<0.05) and striatum (Bonferroni corrected p<0.05) in each CN(Aβ-) and
AD(Aβ+). There was also an interaction effect of education and APOE ε4 allele on the memory performance
in each CN(Aβ-) and AD(Aβ+) (uncorrected p<0.05). APOE ε4 carriers of both groups
showed opposing slopes with each other in the correlation between the education years and Aβ load,
Conclusion: The current results suggest a possible explanation of the differential effects of education
and APOE ε4 allele interactions on AD pathology and memory function at the beginning and end of
AD progress. However, further study with a validating cohort is needed for confirming this explanation.