Cerebral white matter lesions are not associated with apoE genotype but with age and female sex in Alzheimer's disease

Cerebral white matter lesions, such as leukoaraiosis, may be a result of damage from cerebral ischaemia, and may also be associated with the degenerative process in Alzheimer's disease. The apolipoprotein epsilon4 (apoepsilon4) genotype is a genetic risk factor for both Alzheimer's disease and ischaemic brain damage through acceleration of atherosclerosis. The aim was to determine whether apoepsilon4 may be related to the formation of cerebral white matter lesions in Alzheimer's disease. The association of apoE genotype, sex, age, and the presence of several vascular risk factors, with the presence of white matter lesions in 55 patients clinically diagnosed with Alzheimer's disease was investigated. The cerebral white matter lesions were identified by T2 weighted MRI and classified on a 4 grade scale from no lesion to diffuse lesion. The odds ratio (OR) of the factors mentioned above to the presence of white matter lesions was determined and tested by Fisher's exact test. The association of the lesion grades with these factors was analysed by non-parametric tests. The apoE 4 genotype was strongly associated with Alzheimer's disease (p=0.0001), but not associated with the presence or the degree of cerebral white matter lesions in Alzheimer's disease (OR=1.09, p>0.99). Aging (>70 years old) was a significant risk factor for white matter lesions (OR=7.2, p=0.0006) and age was significantly correlated with the lesion (p=0.0075). The OR of female sex to the lesion grades was 2.89 (p=0.084) and the lesion grade of female sex was significantly higher than that of the male sex (p=0.047). Other vascular risk factors were not significantly associated with the presence of white matter lesions. These findings suggest that there is a sex difference in white matter pathology in Alzheimer's disease.