Low premorbid IQ may exacerbate the cognitive effects of apolipoprotein ε4 (APOE ε4): a multi-ethnic cross-sectional study from HABS-HD.

Apolipoprotein allele 4 (APOE ε4) is associated with lower IQ scores during childhood and adolescence, but the influence of APOE ε4 and low IQ on late-life cognition is unknown. This study examines the association between APOE ε4 and cognitive outcomes based on premorbid intellectual ability (pIQ) and ethnic background.