Sex Difference in the Association of APOE4 with Memory Decline in Mild Cognitive Impairment

Abstract

Our aim was to examine whether the influence of apolipoprotein E4 (APOE4) genotype on cognitive decline differs in male and female across the Alzheimer's disease (AD) continuum. Among individuals with normal cognition (NC; n = 415), mild cognitive impairment (MCI; n = 870), and AD (n = 334), we investigated the longitudinal associations of APOE4 genotype and sex with cognitive decline over 13 years. Our cognitive outcomes were Rey Auditory Verbal Learning Test (RAVLT) total learning score and delayed recall and Mini-Mental State Examination (MMSE) score. There were significant effects of the APOE4×sex interaction on change in verbal memory in the MCI group, but not the NC or AD group. Specifically, among individuals with MCI, female APOE4 carriers had a steeper decline in RAVLT total learning score, but not delayed recall or MMSE score compared to all other groups (APOE4 + /Male, APOE4-/Female, APOE4-/Male). In conclusion, female APOE4 carriers have faster rates of memory decline than their male counterparts among MCI individuals.

Keywords: APOE; Alzheimer’s disease; memory decline; sex differences.