Background: The mediating roles of neuropathologies and neurovascular damage in the relationship between early-life education and later-life cognitive function are unknown.
Objective: To examine whether Alzheimer's and neurovascular biomarkers mediate the relationships between education and cognitive functions.
Methods: Data were from 537 adults aged 55-94 in the Alzheimer's Disease Neuroimaging Initiative 3. We tested whether the relationships between education (continuous, years) and cognitive function (memory, executive functioning, and language composites) were mediated by neuroimaging biomarkers (hippocampal volumes, cortical gray matter volumes, meta-temporal tau PET standard uptake value ratio, and white matter hyperintensity volumes). Models were adjusted for age, race, sex/gender, cardiovascular history, body mass index, depression, and Apolipoprotein E-ɛ4 status.
Results: Hippocampal volumes and white matter hyperintensities partially mediated the relationships between education and cognitive function across all domains (6.43% to 15.72% mediated). The direct effects of education on each cognitive domain were strong and statistically significant.
Conclusions: Commonly measured neurobiomarkers only partially mediate the relationships between education and multi-domain cognitive function.
Keywords: Alzheimer’s disease; brain aging; cognitive aging; education; hippocampus; tau; white matter hyperintensities.