Effect of the apolipoprotein E ε4 allele on white matter hyperintensities in dementia

Background and Purpose - The clinical significance of the apoE ε4 allele in white matter changes in patients with dementia has been a subject of debate. We studied the association between the apoE ε4 allele and white matter hyperintensities (WMHs) before and after control for (1) potential vascular risk factors and (2) the presence of lacunar infarcts in patients with dementia. Methods - The subjects were 131 patients with dementia who had either Alzheimer's disease or vascular dementia, or a combination of these 2 types of dementia, with or without WMHs, lacunar infarcts, or both. The association of the ε4 allele with WMHs was examined before and after control for age, sex, duration of symptoms, education level, severity of dementia, presence of lacunar infarcts, and potential vascular risk factors, including hypertension, diabetes mellitus, lipid disorders, smoking habit, drinking habit, and cardiac diseases. Results - WMHs were observed in 73 (55.7%) of the patients. Neither the number of apoE ε4 alleles nor their presence was significantly associated with WMHs before or after control for the potential confounding factors. Multiple logistic regression analyses revealed that age, the presence of hypertension, and the presence of lacunar infarcts were independently associated with WMHs. Conclusions - The apoE ε4 allele was not associated with WMHs in patients with dementia. The fact that WMHs were significantly associated with hypertension and lacunar infarcts may indicate an ischemic origin of WMHs.