Longitudinal study of carotid atherosclerosis and white matter hyperintensities: the EVA-MRI cohort.

BACKGROUND AND PURPOSE: White matter hyperintensities (WMHs) are often observed on cerebral magnetic resonance imaging (MRI) of elderly individuals. Epidemiological studies have shown that age and hypertension are associated with WMHs, suggesting a vascular mechanism in WMH pathogenesis. In a population-based prospective study, we examined the association of carotid atherosclerosis measured at baseline and 4-year follow-up with severity of WMHs assessed at 4-year follow-up.

METHODS: The sample consisted of 640 healthy subjects aged 59-71 years at entry enrolled in the prospective EVA Study. Systolic and diastolic blood pressures were measured at each wave. Ultrasonographic measures of intima-media thickness (IMT) of the common carotid arteries and plaques were made at baseline and at 4-year follow-up examination. An MRI examination was performed at 4-year follow-up. The presence and severity of WMHs were evaluated by a single radiologist.

RESULTS: After adjusting for age, gender, and hypertension, the presence of carotid plaques at baseline was significantly associated with the presence of severe WMHs 4 years later [odds ratio (OR) = 1.70; 95% confidence interval (CI): 1.05-2.74]. The association was stronger in men than in women. A 0.1-mm increase of baseline IMT was associated with an increased risk of severe WMHs in both sexes (adjusted OR = 1.17; 95% CI: 0.96-1.41), but the association was not significant (p = 0.12). Cross-sectional relationships between carotid plaques and severe WMHs at 4-year follow-up showed that the risk of having severe WMHs was stronger in the group of subjects who had already plaques at study entry compared to the group of subjects whose plaques occurred during 4-year follow-up.

CONCLUSION: This study confirmed an association between carotid atherosclerosis and WMHs independently of age and hypertension. It also suggested that the older the carotid plaques, the higher the risk of having severe WMHs.