In that the small blood vessels in the brain are especially susceptible to damage from even moderately elevated blood pressure, which can cause damage to the white matter served by those vessels, a number of previous studies have found that damage to white matter, as indicated by the presence of white matter lesions (WMLs), appears to be an independent risk factor for dementia.  Sylvia Wassertheil-Smoller, from Albert Einstein College of Medicine.(New York, USA), and colleagues analyzed data from the Women's Health Initiative Memory Study (WHIMS), part of the Women's Health Initiative (WHI), the largest multi-site longitudinal study looking at health risks among postmenopausal women.  The researchers reviewed data on 1,403 women, ages 65 years and older.  Upon enrolling in the study and annually during their participation in it, the women had their blood pressure measured and underwent tests to measure their cognitive ability. Some of the study subjects also underwent magnetic resonance imaging (MRI) All of these women were free of dementia when they enrolled.  The MRI studies revealed that women who, on entry to the WHIMS trial, had elevated blood pressure (systolic blood pressure at or above 140 mmHg, or diastolic blood pressure at or above 90 mmHg, or being on antihypertensive drug therapy), had significantly higher amounts of white matter lesions (WMLs) when they underwent MRIs eight years later. The team concludes that: “The results of the study reinforce the relationship of hypertension and [blood pressure] control and white matter abnormalities in the brain. The evidence to date supports tight control of [blood pressure] levels, especially beginning at younger and middle age as a possible and perhaps only way to prevent dementia.”