NIH study finds stroke risk factors may lead to cognitive problems
High blood pressure and other known risk factors for stroke also increase the risk of developing cognitive problems, even among people who have never had a stroke.
Balintfy: Strokes, which affect some 795,000 Americans each year, can cause a host of cognitive problems, including effects on memory, speech and language, and everyday problem solving.
Koroshetz: There are a couple of different forms of stroke.
Balintfy: Dr. Walter Koroshetz is deputy director at the NIH institute researching the brain and nervous system.
Koroshetz: A way to think about it is two major classes. One is bleeding into the brain and the other one is blockage of blood vessels which cause what we call ischemic strokes.
Balintfy: Dr. Koroshetz explains that these ischemic strokes are more common, tend to accumulate as people age, and have been associated with cognitive decline in the elderly.
Koroshetz: We are talking about cognitive decline as people losing their edge, having trouble doing things that are important to their work or their lifestyle.
Balintfy: Now new findings from an NIH-funded study, which has followed more than 30,000 people, show the same risk factors for stroke also increase the risk for cognitive decline.
Koroshetz: Well in this study, the major risk factor was hypertension, and in terms of stroke, hypertension is the major risk factor for stroke; and again here, it's the major risk factor affecting cognitive impairment.
Balintfy:Dr. Koroshetz points out that hypertension, or high blood pressure is manageable.
Koroshetz: The way to manage hypertension is to take blood pressure medicines, to reduce your weight, and to get exercise.
Balintfy: He hopes this study will be a motivating factor for people to reduce their risk.
Koroshetz: So we can control our blood pressure; we can control our weight; we can get exercise; and those things are usually what people associate with better cardiac health and preventing heart attacks. The message here is that it actually promotes brain health.
Balintfy: Another key message from this recent study, published in the Journal Neurology, is that African Americans are at higher risk.
Koroshetz:This study, REGARDS study, is funded to look at a large population, particularly African Americans and Caucasians to compare the risks and trying to understand why African Americans have the highest risk.
Balintfy: And the researchers have made other interesting findings:
Koroshetz: They found that some of the increased risk is related to more high blood pressure, more diabetes, slightly increased weight called body mass index; and those were things that now are kind of out there in the open to get controlled. However, there does seem to be a significant percentage of the risk which is unexplained.
Balintfy: Dr. Koroshetz says another intriguing piece of the study is that the risk of stroke is also dependent on where people grow up. He notes stroke rates are highest in what's call the "Stroke Belt" in the Southwestern United States. That includes North Carolina, South Carolina, Tennessee, Kentucky, Mississippi, Arkansas and Alabama.
Koroshetz: So if you grew up in the Stroke Belt and then moved in your 20s or 30s, you seem to carry the risk that you had that people in the Stroke Belt had. So it almost suggests there's something going on earlier in life with regard to these risks for stroke.
Balintfy: There may also be a cumulative effect of "silent strokes" adding up to cognitive decline.
Koroshetz: MRI scans are incredibly sensitive to any type of structural changes in the brain. So, one can see now strokes in the brain that occurred in areas that didn't give symptoms and those are called silent strokes. We've known about them for a long time but it's only recently that people have been able to do MRIs on populations to show what the incidence is, and it's strikingly high and it goes up exponentially to the point where if you're 90 years old, you have a 40% chance of having had a silent stroke. Most people with silent strokes have more than one as well.
Balintfy: Dr. Koroshetz says that there's potentially a silent epidemic going on where there's injury to the brain due to very small strokes that go unnoticed by people and their physicians but may cause the cognitive impairment.
Koroshetz: Those changes in the MRI now give us a potential window into identifying people who are at the highest risk of developing this kind of vascular cognitive impairment and that I think is exciting as we go forward. It's also a little daunting because of the expense of MRI scans and the idea of everyone having an MRI scan to look for this. I think it's not a crazy idea that this will be something important in the future.
Balintfy: But Dr. Koroshetz adds, prevention is key: managing high blood pressure, maintaining a healthy weight, and keeping physically active help not only heart health, but reduce stroke risk and reduce cognitive decline. For more information on stroke research and this study, visit www.ninds.nih.gov. This is Joe Balintfy, at the NIH in Bethesda, Maryland.
About This Audio Report
Reporter: Joe Balintfy
Sound Bite: Dr. Walter Koroshetz
Topic: stroke, strokes, ischemic stroke, stroke risk, stroke risk factors, silent stroke, stroke prevention, cognitive decline, cognitive problem, cognitive impairment, hypertension, high blood pressure, MRI
Additional Info: NIH study finds stroke risk factors may lead to cognitive problems