DHA association with spatial navigation performance from Cohort 2 (n = 46). There was a significant interaction between APOE genotype and DHA on left egocentric path integration (t = −2.06, P = 0.04). Total DHA in erythrocytes was inversely related to egocentric path integration in cognitively intact APOE ε3ε4 carriers (n = 22) only. No significant association was found in the ε3ε3 carrier group.