EXPLORATORY ASSOCIATIONS BETWEEN EDUCATIONAL QUALIFICATION AND PLASMA APOE AMONG COGNITIVELY HEALTHY AGING INDIVIDUALS

The APOE genotype is a major genetic risk factor for late-onset Alzheimer's disease. It encodes apolipoprotein E (apoE), which facilitates lipid distribution to neurons and other cells. Human apoE circulating levels are associated with higher dementia-related mortality and may serve as a non-genetic biomarker and intervention target. Here, we explored the link between peripheral apoE levels, education, and cognitive performance in 5,098 cognitively unimpaired older adults (mean age = 65.9, SD = 9.07) from the second wave of the English Longitudinal Study of Ageing (ELSA). Preliminary analyses were conducted using RStudio (version 4.4.0), with significance set at p < 0.05. A polyserial correlation assessed the relationship between plasma apoE concentration and education level, revealing a weak positive association (ρ = .07, p < 0.001), likely driven by the large sample size rather than a meaningful effect. No significant correlation was found between apoE levels and cognitive index, r(5096) = 0.02, p = 0.12. A multiple linear regression model examined plasma apoE levels as a function of education, controlling for age, sex, and cognitive index. Participants without formal qualifications had slightly higher apoE levels than those with university degrees (β = 0.12, p = 0.01), while those with high school diplomas showed a borderline increase (β = 0.09, p = 0.07). These findings suggest that plasma apoE levels are independent of educational attainment and cognitive performance. This implies that peripheral apoE concentrations reflect metabolic processes rather than neurocognitive or psychosocial factors, indicating distinct biological pathways from those underlying cognitive reserve proxies.