Interaction effect of Alzheimer's disease pathology and education, occupation, and socioeconomic status as a proxy for cognitive reserve on cognitive performance: in vivo positron emission tomography study

Aim Educational attainment, occupation, and socioeconomic status have been regarded as major factors influencing cognitive reserve (CR). This study aimed to investigate the interaction effect of amyloid-β/tau burden and education/occupation/socioeconomic status as a proxy for CR on cognitive performance. Methods We analyzed the datasets of the Alzheimer's Disease Neuroimaging Initiative. We included clinically normal subjects and patients with mild cognitive impairment or Alzheimer's disease who had undergone a florbetapir scan within 1 year of a flortaucipir (AV-1451) scan (n = 127). Partial correlation analysis between the standardized uptake value ratio of florbetapir/AV-1451 and the proxy for CR was performed with the 13-item Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-cog) score as a covariate. Stepwise multiple linear regression analysis was performed to determine the predictors of ADAS-cog performance based on the interaction between the imaging biomarkers and the proxy for CR. Results We found a significant positive partial correlation between educational level and tau pathology in Braak stage 1/2 areas, and we observed significantly higher tau accumulation among participants with higher education when ADAS-cog score was used as a covariate. The interaction between tau and education was a good predictor of cognitive function, with higher tau accumulation showing a greater association with higher ADAS-cog score among participants with less education than among those with more education. Conclusion Our findings indicate the protective effect of education against cognitive dysfunction in early-stage Alzheimer's disease pathology and suggest that education may exert a beneficial effect by reducing the adverse cognitive consequences of tau aggregation.