Longitudinal study of blood pressure and white matter hyperintensities

Objective: To investigate the relationship between baseline hypertension and severity of white matter hyperintensities (WMH) at 4-year follow-up in a sample of subjects aged 59 to 71 years old at entry. Methods: Subjects were participants in the Epidemiology of Vascular Ageing study, a longitudinal study on vascular aging and cognitive decline. At 4-year follow-up, 845 subjects had a cerebral MRI. MRI examinations were read by a single rater to determine the severity of WMH, ranging from absent to severe. Hypertension at each wave of the study was defined as systolic blood pressure ≥160 mm Hg, diastolic blood pressure ≥95 mm Hg, or use of antihypertensive medication. Results: Hypertension at baseline was significantly associated with an increased risk of having severe WMH at 4-year follow-up. When taking into account both blood pressure levels and antihypertensive drug intake, analysis showed that the risk of having severe WMH was significantly reduced in subjects with normal blood pressure taking antihypertensive medication compared with those with high blood pressure taking antihypertensive agents. Cross-sectional relationships between hypertension and WMH at 4-year follow-up showed that the frequency of severe WMH was significantly higher in people who were hypertensive at both baseline and 4-year follow-up than those who were hypertensive only at 4-year follow-up. Conclusions: Hypertension is a major risk factor for severe WMH. Subjects taking antihypertensive drugs and who have controlled blood pressure had a reduced risk of severe WMH. Longitudinal studies are needed to investigate whether reduction of the development of WMH, by treatment and prevention of hypertension, might reduce the subsequent risk of cognitive deterioration or stroke.