Apolipoprotein E genotypes in hospitalized elderly patients with vascular dementia

Background: Polymorphism in the apolipoprotein E ( APOE) gene is the major genetic risk factor associated with late-onset Alzheimer's Disease ( AD). However, it is still unclear if a relationship exists between the APOE epsilon 4 allele and vascular dementia (VaD) in elderly subjects. Objectives: To evaluate the prevalence of APOE alleles in elderly patients with VaD compared to AD patients and to control subjects with no cognitive impairment (NoCI). Patients and Methods: We evaluated 396 consecutive patients aged 6 65 years with definite or suspected cognitive impairment with a clinical (Mini-Mental State Examination, Clinical Dementia Rating, Geriatric Depression Scale), functional ( Activities of Daily Living, Instrumental Activities of Daily Living), comorbidity ( Cumulative Illness Rating Scale) and instrumental (CT scan, NMR) assessment. Diagnosis of dementia was made according to NINCDS-ADRDA and NINDS-AIREN Work Group and the DSM-IV. APOE genotypes were analyzed by a recently described method resulting in positive/negative chain reaction products for each APOE genotype. Statistical analysis was carried out using the Pearson chi(2), the Kruskal-Wallis test and the ANOVA post hoc comparisons. Results: A total of 287 elderly patients ( males = 138, females = 149, mean age = 77.8 +/- 8 6.9 years, range = 65 - 98) with diagnoses of VaD ( n = 97), AD ( n = 82) or NoCI ( n = 108) were included in the study. A significantly higher APOE epsilon 4 allele frequency was observed in AD patients compared to VaD and/or NoCI subjects, while no differences were found between VaD patients and subjects with NoCI ( AD = 24.3%, VaD = 10.3, NoCI = 8.7, p < 0.05). Furthermore, a significantly lower APOE epsilon 3 allele frequency was observed in AD patients compared to VaD and/or NoCI subjects but not between VaD and NoCI patients ( AD = 71.3%, VaD = 80.9, NoCI = 83.4, p < 0.05). No significant differences were observed in the APOE epsilon 2 allele ( VaD = 8.8%, AD = 4.4, NoCI = 7.9, p = n. s.) among the 3 groups. Conclusions: In this population, the frequency of the APOE epsilon 4 allele is lower in VaD than in AD. Copyright (C) 2007 S. Karger AG, Basel.