This explains why clinicians pull out the BP cuff at nearly every office visit. By tracking BP, they can ensure levels—on average—stay at or below the 130/80 sweet spot. If BP levels creep upward, doctors can advise patients to make lifestyle changes (for example, eat less salt, get more exercise) or even prescribe medication to reduce BP.
But what if having high BP isn’t the only property of this critical measure that increases health risk? This is exactly what Min-Woong Sohn, Ph.D., suspects, and he was recently awarded a Department of Defense grant to explore his hypotheses about the impact of variable blood pressure on human health.
BP variability impact on multiple sclerosis
Sohn, a professor and the F. Douglas Scutchfield Endowed Chair in Health Services and Systems Research in the University of Kentucky (UK) College of Public Health’s Department of Health Management and Policy, is specifically interested in whether BP variability speeds up the progression of multiple sclerosis (MS).
MS is a chronic, progressive disease that affects the nervous system. It is believed to be a disorder in which the body attacks itself by mistake, resulting in damage to the protective covering of nerve cells that subsequently impedes signals to and from the brain. Progression of the disease varies greatly from person to person, ranging from tingling and numbness to blindness and paralysis. There is no cure for MS. Treatment typically focuses on managing symptoms and slowing the progression of the disease.
“My research has shown that high BP variability negatively impacts the microvasculature in the kidneys, the eyes, and also the nervous system,” said Sohn. Previous research has also suggested that variable systolic BP (the larger of the two BP numbers) is linked to cognitive dysfunction in Parkinson’s disease patients and cognitive decline in older adults.
Because MS, like Parkinson’s and dementia, is also a neurological disease, Sohn hypothesizes that systolic BP variability may affect MS progression. In fact, preliminary studies in MS patients hint that those with higher systolic BP variability have greater MS-related disability. Sohn emphasized a crucial aspect of his hypothesis:
“We suspect that high BP variability is harmful even for people with normal average blood pressure as well as hypertensive individuals.”
Cardiovascular risk factors and links to MS progression
In addition to exploring the potential impacts of systolic BP variability, Sohn and colleagues will also investigate whether other well-established cardiovascular risk factors (such as high BP, high cholesterol, obesity and smoking) are linked to MS progression. They also will assess whether treating these factors has any bearing on the progression of MS.
Much of the previous research in this domain has used insurance claims data, a less-than-optimum approach producing less-than-definitive findings. Sohn’s study, “Systolic Blood Pressure Variability and Multiple Sclerosis Disease Progression,” uses existing data from three MS clinical trials involving 1,200 individuals who, in aggregate, represent the full range of MS-disease progression.
Patients were assessed every three months for two years to gather data on visit-to-visit variability of systolic BP and a wide range of signs and symptoms that characterize MS progression. This study represents the largest longitudinal (repeated observations over time) study of the role of cardiovascular risk factors in MS disease progression.
Principal investigator Sohn is collaborating with co-investigators Myla Goldman, MD, Department of Neurology, Virginia Commonwealth University, and Jennifer Lobo, Ph.D., Department of Public Health Sciences, University of Virginia.
Impact of study and future research
When asked about the potential impact of his study, Sohn explained:
“We’ve already demonstrated that increased pain and fatigue are connected to systolic BP variability in MS patients. If we find a connection between BP variability and MS disease progression—and I suspect we will—researchers and clinicians will need to take systolic BP variability a lot more seriously.”
Future research may explore the causal mechanisms by which BP variability influences MS disease progression. Preliminary evidence suggests that variable systolic BP may induce inflammation in cerebral blood vessels, thereby causing nervous system dysfunction. Such mechanisms require further investigation.
Finding ways to translate research findings into clinical practice will also be necessary.
“How might we treat normotensive individuals with high BP variability? That’s the next challenge we may be facing. It’s a problem that nobody has given much thought to, but it would represent a new and different approach to managing blood pressure,” Sohn conjectured.
If Sohn and colleagues find that treating the other established cardiovascular risk factors slows MS progression, clinicians may gain additional tools to manage the disease.
Sohn is eager to undertake his recently funded study and grateful to be an early explorer of what may prove to be an important mechanism driving disease processes.
“Our study is the first of its kind. It has the potential to open an entirely new line of research which could change the way MS patients are cared for.”
This material is based upon work supported by, or in part by, the U.S. Army Research Office under award number W81XWH2210955. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the view of the U.S. Army Research Office.
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