Age-Related Association between Apolipoprotein E ε4 and Cognitive Function in Japanese Patients with Alzheimer's Disease

AIMS: In the present study, we investigated whether apolipoprotein E (APOE) polymorphisms influenced the cognitive function of Japanese patients with Alzheimer's disease (AD) at certain ages. METHODS: Among 200 outpatients with dementia and amnestic mild cognitive impairment, 133 Japanese patients with AD were recruited and divided into two genotypic groups: APOE ε4 carriers and noncarriers. Then, we compared several neuropsychological test scores between the two genotypic groups for two different generations: 70s (70-79 years) and 80s (80-89 years). RESULTS: The total Mini-Mental State Examination score (p < 0.05) and one of its subtest scores, the 3-stage command score (p < 0.01), were significantly lower for the ε4 carriers than for the noncarriers among patients in their 80s, but not among those in their 70s. The duration of illness differed significantly between the ε4 carriers and the noncarriers among subjects in their 80s but was not correlated with cognitive function. CONCLUSION: The present results suggest that APOE may significantly influence comparatively simple memory processing in certain generations of Japanese patients with AD.