Among dementia participants, APOE ε4 status influenced only naming and memory scores.<h4>Discussion</h4>APOE ε4 carriers in this DRC cohort showed greater cognitive decline and neurodegeneration, highlighting its significant impact in African populations.<h4>Highlights</h4>Apolipoprotein E (APOE) ε4 was more frequent in dementia cases than in healthy controls in a Democratic Republic of the Congo cohort. Here, APOE is linked to Mental deterioration.