ACADEMIC PERFORMANCE AND RISK OF ALZHEIMER’S DISEASE AND DEMENTIA IN THE NUN STUDY: ARE HIGH GRADES A PROTECTIVE FACTOR OR LOW GRADES A RISK FACTOR?

Abstract

The association of educational attainment with risk of Alzheimer's disease (AD) is well established. The effect of other education-related factors, however, is less well characterized. Our objectives were to determine: 1) if academic performance in high school English and algebra courses was associated with the risk of AD and dementia, and 2) if high academic performance decreased, or low academic performance increased, the risk of these conditions. The Nun Study is a longitudinal study of 678 religious sisters aged 75+ years at baseline. To minimize confounding by education-related factors, the analytic sample was restricted to a homogeneous group of university-educated teachers with English as a primary language. Final grades for first-year high school English and math courses were obtained from convent archives. Low academic performance was defined as below 80% (i.e., below an ‘A’); grades 80% or higher were further divided into intermediate (80%-95%) and high (>95%) levels of performance. Dementia was diagnosed based on DSM-IV criteria. AD was diagnosed based on meeting criteria for both clinical dementia and AD neuropathology (NIA-Reagan intermediate/high likelihood). Multiple logistic regression models were used to assess the association of academic performance with dementia (n=283) or AD (n=220) adjusted for age, education (bachelor's vs. master's degree or higher) and apolipoprotein E-ε4. Low academic performance (below vs. above 80%) in English was significantly associated with both AD (odds ratio [OR]=2.83; 95% confidence interval [CI]=1.21-6.70) and dementia (OR=2.09; 95% CI=1.04-4.28). For algebra, however, the association was significant only for AD (OR=3.25; 95% CI=1.44-7.40). When low and high academic performance were compared to intermediate levels, neither English nor algebra grades were significantly associated with dementia. Low academic performance in English (OR=2.79; 95% CI=1.19-6.65) and algebra (OR=3.07; 95% CI=1.34-7.09) were risk factors for AD; however, high performance showed no significant protective effect. Low academic performance in high school English and algebra courses was a significant risk factor for AD even after stringent control for education-related factors. In contrast, high academic performance was not a significant protective factor. Low academic performance may provide predictive power for AD in addition to the established effects of educational attainment.