In addition, we observed a main effect of APOE status on hippocampal volume only in ε4/ε4 carriers. Individuals with the ε4/ε4 genotype displayed a reduction in total hippocampal volume of 109.1 mm3 compared to ε3/ε3 carriers (P = 3.9 × 10−9). We did not detect statistically significant associations of ε3/ε4 or ε2/ε3 and total hippocampal volume in this model.
