APOE4 Status and Cognitive Function in Middle-aged and Elderly People

APOE is one of the prominent genes involved in the increased risk of developing Alzheimer's disease, but its effect on cognition in patients who are not yet diagnosed with dementia or mild cognitive impairment is relatively understudied. We aimed to examine the effect of ApoE4 on cognitive performance in unimpaired middle-aged and elderly persons.

Our study included 51 cognitively unimpaired participants divided into ApoE4 positive patients and controls by APOE genotyping. The following clinical and demographic characteristics were collected: age, gender, education, social status, BMI, history of medical or psychiatric disorders. Patients with current anxiety or depressive disorders were excluded. Cognitive function was evaluated using MMSE, Rey Auditory-Verbal Learning Test, Rey Complex Figure test, TMT A and B and verbal fluency test. The two groups were matched for age, sex, and education. Categorial data was analyzed using Chi-Square and continuous data using Student-T test (parametric variables) or Mann-Whitney test (non-parametric variables). Statistical significance was considered at p≤.05.

There were 11 (21.6%) ApoE4 positive patients and 40 (78.4%) controls. There were no significant differences between the groups regarding socio-demographic and clinical characteristics. The ApoE4 positive group performed slightly worse on cognitive evaluations compared to controls but only the mean scores of the Rey Complex Figure Test - Memory reached statistical significance (p=.019).

Cognitive evaluation generally rendered lower scores in the ApoE4 group compared to the control group. However, only visual memory impairment scores were significantly lower in the ApoE4 positive individuals than in controls.