Abstract
Background
Cognitive reserve (CR) is partially responsible for inter-individual differences in developing dementia due to Alzheimer’s disease (AD). However, education years, as the primary proxy of CR, does not capture various life experiences, vocational background, and resources available to those who did not have an opportunity to complete formal education. We compared education years against Hollingshead Four-Factor Index of Socioeconomic Status (SES-Adults) to examine the latter’s utility as a better proxy of cognitive reserve. The SES-Adults is a survey collecting information on marital status, retired/employed status, educational attainment, and occupational prestige for participants and their partners. The survey results are then converted into one of the 5 social class categories including low, working, middle, upper-middle, and upper socioeconomic status.
Method
A cross-sectional study was conducted on a cohort of adults and older adults (n = 264) with mean age of 67.96 years. Participants were recruited from a longitudinal study investigating neuropsychological and biological correlates of dementia, namely the Western Australian Memory Study (WAMS). We examined the relationships between education years and the SES-Adults scores, with cognitive function and amyloid load while controlling for age, gender (male/female), and APOE ε4 carriage. Amyloid load was measured using 18F-NAV-469 tracer.
Result
The cohort included 190 females and 74 males with 80 APOE ε4 carriers (available genotyped individuals = 203). Linear regression results showed education years was significantly correlated with both general cognitive function (MoCA) and amyloid load (R2 = 0.2935, Adjusted-R2 = 0.2513; p<0.026) while controlling for the effects of age, gender, and APOE ε4 carriage. The SES-Adults was not significantly related to cognition or amyloid load (p = .914). When SES was included in regression model, the relationships between education years and outcome measures turned non-significant.
Conclusion
We found education years to be significantly related to both cognition and amyloid load. However, no significant results was noted for the SES-Adults. This cross-sectional study showed that education is a reliable CR proxy as compared to a comprehensive measure of socioeconomic status(SES- Adults) .