Numerous large, cohort studies have linked midlife hypertension to mild cognitive impairment and dementia later on. Some of these studies found a higher risk of lesions in the brain’s white matter in older age among people with high blood pressure in their 50s.
The white matter of the brain consists of bundles of axons, which are the thin elongations of neurons. White matter is “white” due to myelin — the protective substance that covers the axons. Unlike gray matter, the white matter continues to evolve in our adulthood and midlife.
Previous studies have tied abnormalities in the brain’s myelin, such as the thinning of this layer, with a range of neurological conditions, including Alzheimer’s and other dementias.
White matter lesions, which appear on an MRI scanner, reflect such myelin disruptions. White matter lesions can also indicate high water content, higher glial cell sensitivity to injury, porous brain blood vessels, or ministrokes.
New research explores the connection between midlife hypertension and white matter lesions, which may lead to cognitive impairment later in life. Specifically, a team of researchers asked themselves if intensive blood pressure treatment correlates with a limited “progression of small vessel ischemic disease, as reflected by cerebral white matter lesion volume.”
Dr. Nick Bryan, Ph.D., from the Department of Diagnostic Medicine at the University of Texas at Austin, is the corresponding author of the new paper.Dr. Bryan and team examined the brain scans of 449 participants and found that intensive control of blood pressure in their 50s did, indeed, corresponded with a lower likelihood of white matter lesions later on. The findings of the research now appear in JAMA.
The researchers examined the brain scans of the participants who had enrolled in the National Institutes of Health’s (NIH) Systolic Blood Pressure Intervention Trial (SPRINT).
As part of SPRINT, the participants — who were 50 years old on average at baseline and at high cardiovascular risk — undertook brain scans at the beginning of the study and 4 years later.
During this time, the participants received either standard treatment, which reduced systolic blood pressure to less than 140 millimeters of mercury (mm Hg) or intensive treatment to lower systolic blood pressure below 120 mm Hg.
Over the 4 years, the total volume of white matter lesions rose by 0.92 cm3, on average, in the intensive treatment group. By contrast, white matter lesion volume rose by 1.45 cm3, on average, among the participants who received standard treatment.
“Intensive treatment significantly reduced white matter lesion accumulation in people who had a higher chance of experiencing this kind of damage because they had high blood pressure,” reports study co-author Dr. Clinton B. Wright, the director of the Division of Clinical Research at NIH’s National Institute of Neurological Disorders and Stroke (NINDS).
Another co-author of the study, Lenore J. Launer, Ph.D., who is a senior investigator at NIH’s National Institute on Aging (NIA) Laboratory of Epidemiology and Population Sciences, also comments on the findings.
She says: “SPRINT MIND has produced promising initial results in the battle against the nation’s growing problem with aging brain disorders. Both the brain scans and cognitive tests reinforce the potential benefits that intensive blood pressure management may have on the brain.”
“We hope that these findings will become the foundation for future studies on how to protect the brain throughout a person’s life,” adds Launer.
The findings strengthen the results of a previous study that found intensive blood pressure control reduces mild cognitive impairment occurrence.
“These findings on white matter lesions — primarily in the aggressive control of blood pressure — are encouraging as we continue to advance the science of understanding and addressing the complexities of brain diseases, such as Alzheimer’s and related dementias,” adds Dr. Richard J. Hodes, the director of the NIA.
Writer: Sakshi Gupta