Stroke and dementia are more likely to affect people with high blood pressure. Understand the links and learn what you can do to minimize your risk.
Many people with high blood pressure know that they could be at risk for stroke and heart attack. However, too many people, despite what they may know, still are not motivated by these facts to get their high blood pressure under control. Now a new risk of high blood pressure is emerging: the possible connection between uncontrolled blood pressure and dementia. Important new studies link high blood pressure, especially in midlife, to an increased risk for dementia later in life.
Scientists are working hard to learn more about this connection. In the meantime, don’t take unnecessary risks. Keep your blood pressure under control. Know your risks.
Scientists around the world are learning more about cellular changes in the brain that can lead to dementia, including Alzheimer’s disease. This research may someday lead to new treatments to prevent or slow the most serious forms of dementia. In the meantime, though, evidence suggests that vascular dementia—one of the most common dementia diagnoses—may be preventable. Vascular dementia usually occurs due to the cumulative impact of multiple strokes, including small “silent” strokes that occur unnoticed as we age. High blood pressure is the main culprit. Over time, high blood pressure weakens the arteries, leads to strokes, and may bring on processes in your body that can cause dementia. There are many ways that you can improve your chances of healthy brain aging—from taking blood pressure control medicines prescribed by your doctor to lifestyle changes such as exercise, weight loss and quitting smoking.
What is dementia? Most of us know someone—a friend, a family member—living with dementia. Many people think of it as a single disease with the main symptom being memory loss. However, a number of different diseases can result in dementia, and the word itself describes a group of symptoms that negatively affect how the brain works. Symptoms include memory loss, as well as changes in mental abilities such as reasoning and judgment, in a way that can make it difficult to perform any number of once routine daily activities. Some people with dementia can experience changes in personality, while others may become agitated, delusional or have slowed thinking. Memory loss alone does not mean someone has dementia.
There are different forms of dementia:
- Alzheimer’s disease is the most common form of dementia. There are drugs that may improve the quality of life for people who have it, but there is no cure for the disease.
- Vascular dementia is caused by “silent strokes,” also called infarcts, that can often go unnoticed. Damage to the brain, as a result of multiple strokes over time, gradually leads to a loss of brain function.
Moreover, population-based autopsy studies have shown that many patients who die with dementia often have a combination of both Alzheimer’s pathology and brain injury due to vascular disease or silent strokes, often called “mixed dementia.” Experts now believe that the processes that give rise to vascular disease in the brain and Alzheimer’s disease may converge, dramatically increasing the likelihood and severity of dementia more than either condition alone.
Strokes can cause a host of cognitive disabilities, including effects on memory, speech and language, and everyday problem solving. But even without suffering an obvious stroke, individuals at risk for stroke may experience cognitive impairment as their blood vessels deteriorate. Silent strokes and vascular damage to the “wires” that connect brain regions cause diffuse white matter disease. These brain changes increase one’s risk of later developing age-related cognitive decline and dementia.
The heart and brain are the two hardest working organs in your body. They are so closely linked that the conditions that put one at risk of poor health can affect the other. Here are the important ways they are connected:
- The heart supplies blood to all the parts of your body, including the brain.
- When blood enters the brain, a complicated network of blood vessels distributes oxygen and nutrients to billions of brain cells. Brain health is linked, in part, to the health of blood vessels that supply the brain.
- High blood pressure causes these delicate blood vessels to become scarred, narrowed and diseased. This can affect the bloodstream’s ability to provide nerve cells with the oxygen and nutrients they need to function and survive.
- Over time, damage to the brain’s blood vessels may lead to cognitive impairment and vascular dementia. This damage may begin in middle age, years before people start to have memory and other problems related to dementia.
- High blood pressure can also lead to “diffuse white matter disease” and silent strokes, which are linked to later development of cognitive decline and vascular dementia.
- High blood pressure is the most preventable cause of stroke. As many as 30 percent of stroke survivors develop post-stroke dementia. Scientists believe that the same risk factors that lead to stroke can also lead to cognitive impairment and vascular dementia.
- Stroke occurs when blood circulation to the brain fails either because blood flow is blocked or because a blood vessel ruptures and bleeds into surrounding brain tissue. Brain cells can die as a result and the consequences can be mild to severe depending on the size and location of the stroke.
- Transient ischemic attack, sometimes called a mini-stroke, starts just like a stroke but then resolves leaving no noticeable symptoms or deficits. The occurrence of a TIA is a warning that the person is at risk for a more serious and debilitating stroke.
- Silent strokes show up as multiple areas of ischemic tissue damage (which occurs when an artery to the brain is blocked) on MRI scans or in brains examined after death. In contrast to strokes that cause immediate and obvious consequences, silent strokes go unnoticed because they are so small, or because they occur in areas that are not directly responsible for movement, speech, vision or other critical functions.
- Diffuse white matter disease is a change in brain structure that can be seen on MRI scans in the majority of older people, affecting as many as 80 percent of those older than age 80. Research has demonstrated an association between these white matter lesions and blood pressure levels, with higher blood pressure over time being linked to more extensive areas of white matter damage. Some studies also suggest a link between severe white matter lesions and diminished performance on tests of cognitive function.
- Heart disease is a disorder of the blood vessels of the heart that can lead to a heart attack. A heart attack happens when an artery becomes blocked, preventing oxygen and nutrients from getting to the heart.
“People need to think about how they can decrease their chances of developing dementia in later life. With what we now know, controlling hypertension is at the top of the list,” said Walter Koroshetz, M.D., director of the National Institutes of Health’s National Institute of Neurological Disorders and Stroke.
The best way you can follow Dr. Koroshetz’s recommendation is to manage your risks. A healthy heart and a healthy brain are crucial to health in old age. There are many simple and effective lifestyle changes you can make that will reduce your chance of all types of stroke, heart disease and likely dementia later in life:
- Eat healthy and keep active. Following a healthy eating plan and keeping physically active on a regular basis will significantly lower your risk for heart disease, high blood pressure, type 2 diabetes and other chronic and debilitating health problems.
- Quit smoking. Smoking harms nearly every organ in the body, including the heart. Any amount of smoking, even light or occasional smoking, damages the heart and blood vessels.
- Lower high cholesterol. Reducing your cholesterol will lower your risk for developing a wide variety of serious health issues, including stroke and heart disease.
- Control high blood pressure. Know your blood pressure! If left unchecked, high blood pressure can damage the cells of your arteries’ inner lining and cause a hardening called arteriosclerosis, blocking blood flow to your heart, brain, and kidneys, as well as to your muscles.
- Manage your diabetes. Having diabetes or pre-diabetes puts you at increased risk for stroke and heart disease. You can lower your risk by keeping your blood glucose, blood pressure and blood cholesterol close to the recommended target numbers provided by your doctor.
- Avoid the use of illicit drugs and heavy consumption of alcohol. Generally, an increase in alcohol consumption leads to an increase in blood pressure. The use of illicit drugs, such as cocaine and methamphetamines, can cause stroke.
- Stick to the plan. This is the hard part, but keeping your heart and brain as healthy as you can will lead to better overall health as you age.
- Take your medications. Your doctor may recommend taking aspirin or other drugs daily to prevent stroke and heart attack, especially if you have hypertension.
- Start early! Preventing stroke and heart disease is more effective if started in midlife. Studies also find that controlling blood pressure may also reduce risk of dementia.