STROKE
Stroke is a disease that affects the arteries leading to and within the brain. It is the No. 5 cause of death and a leading cause of disability in the United States.
A stroke occurs when a blood vessel that carries oxygen and nutrients to the brain is either blocked by a clot or bursts (or ruptures). When that happens, part of the brain cannot get the blood (and oxygen) it needs, so it and brain cells die.
Impact on Strokes (Stroke Statistics)
About 795,000 Americans each year suffer a new or recurrent stroke. That means, on average, a stroke occurs every 40 seconds.
Stroke kills nearly 129,000 people a year. It is the No. 5 cause of death.
On average, every 4 minutes someone dies of stroke.
About 40 percent of stroke deaths occur in males, and 60 percent in females.
In 2010, worldwide prevalence of stroke was 33 million, with 16.9 million people having a first stroke. Stroke is the leading cause of adult disability.
African-Americans have nearly twice the risk for a first-ever stroke than Caucasians and a much higher death rate from stroke.
For more up-to-date statistics on stroke, please visit: http://www.heart.org/HEARTORG/General/Heart-and-Stroke-Association-Statistics_UCM_319064_SubHomePage.jsp
Types of Stroke
Stroke can be caused either by a clot obstructing the flow of blood to the brain (called an ischemic stroke) or by a blood vessel rupturing and preventing blood flow to the brain (called a hemorrhagic stroke). A TIA (transient ischemic attack), or “mini stroke”, is caused by a temporary clot.
Effects of Stroke
Every stroke is unique, but strokes tend to affect people in common ways.
The brain is an extremely complex organ that controls various body functions. If a stroke occurs and blood flow can’t reach the region that controls a particular body function, that part of the body won’t work as it should.
If the stroke occurs toward the back of the brain, for instance, it’s likely that some disability involving vision will result. The effects of a stroke depend primarily on the location of the obstruction and the extent of brain tissue affected.
Right Brain
The effects of a stroke depend on several factors, including the location of the obstruction and how much brain tissue is affected. However, because one side of the brain controls the opposite side of the body, a stroke affecting one side will result in neurological complications on the side of the body it affects. For example, if the stroke occurs in the brain’s right side, the left side of the body (and the left side of the face) will be affected, which could produce any or all of the following:
- Paralysis on the left side of the body
- Vision problems
- Quick, inquisitive behavioral style
- Memory loss
Left Brain
If the stroke occurs in the left side of the brain, the right side of the body will be affected, producing some or all of the following:
- Paralysis on the right side of the body
- Speech/language problems
- Slow, cautious behavioral style
- Memory loss
Brain Stem
When stroke occurs in the brain stem, depending on the severity of the injury, it can affect both sides of the body and may leave someone in a ‘locked-in’ state. When a locked-in state occurs, the patient is generally unable to speak or achieve any movement below the neck.
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Understanding Stroke Risk
Some stroke risk factors are hereditary. Others are a function of natural processes. Still others result from a person’s lifestyle.
What Stroke Risk Factors Can’t Be Changed?
- Age — The chance of having a stroke approximately doubles for each decade of life after age 55. While stroke is common among the elderly, a lot of people under 65 also have strokes.
- Heredity (family history) — Your stroke risk may be greater if a parent, grandparent, sister or brother has had a stroke. Some strokes may be symptoms of genetic disorders like CADASIL (Cerebral Autosomal Dominant Arteriopathy with Sub-cortical Infarcts and Leukoencephalopathy), which is caused by a gene mutation that leads to damage of blood vessel walls in the brain, blocking blood flow. Most individuals with CADASIL have a family history of the disorder — each child of a CADASIL parent has a 50% chance of inheriting the disease. Visit the NINDS website (opens in new window) or read the AHA/ASA scientific statement (opens in new window) on this topic for more details about CADASIL.
- Race — African-Americans (opens in new window) have a much higher risk of death from a stroke than Caucasians do. This is partly because African-Americans have higher risks of high blood pressure, diabetes and obesity.
- Sex (gender) — Each year, women have more strokes than men, and stroke kills more women than men. Use of birth control pills, pregnancy, history of preeclampsia/eclampsia or gestational diabetes, oral contraceptive use, and smoking, and post-menopausal hormone therapy may pose special stroke risks for women. Be sure to discuss your specific risks with your doctor.
- Prior stroke, TIA or heart attack — The risk of stroke for someone who has already had one is many times that of a person who has not. Transient ischemic attacks (TIAs) are “warning strokes” that produce stroke-like symptoms but no lasting damage. TIAs are strong predictors of stroke. A person who’s had one or more TIAs is almost 10 times more likely to have a stroke than someone of the same age and sex who hasn’t. Recognizing and treating TIAs can reduce your risk of a major stroke. TIA should be considered a medical emergency and followed up immediately with a healthcare professional. If you’ve had a heart attack, you’re at higher risk of having a stroke, too.
What Stroke Risk Factors Can Be Changed?
- High blood pressure — High blood pressure is the leading cause of stroke and the most important controllable risk factor for stroke. Many people believe the effective treatment of high blood pressure is a key reason for the accelerated decline in the death rates for stroke.
- Cigarette smoking — In recent years, studies have shown cigarette smoking to be an important risk factor for stroke. The nicotine and carbon monoxide in cigarette smoke damage the cardiovascular system in many ways. The use of oral contraceptives combined with cigarette smoking greatly increases stroke risk.
- Diabetes mellitus — Diabetes is an independent risk factor for stroke. Many people with diabetes also have high blood pressure, high blood cholesterol and are overweight. This increases their risk even more. While diabetes is treatable, the presence of the disease still increases your risk of stroke.
- Carotid or other artery disease — The carotid arteries in your neck supply blood to your brain. A carotid artery narrowed by fatty deposits from atherosclerosis (plaque buildups in artery walls) may become blocked by a blood clot. Carotid artery disease is also called carotid artery stenosis.
- Peripheral artery disease is the narrowing of blood vessels carrying blood to leg and arm muscles. It’s caused by fatty buildups of plaque in artery walls. People with peripheral artery disease have a higher risk of carotid artery disease, which raises their risk of stroke.
- Atrial fibrillation — This heart rhythm disorder raises the risk for stroke. The heart’s upper chambers quiver instead of beating effectively, which can let the blood pool and clot. If a clot breaks off, enters the bloodstream and lodges in an artery leading to the brain, a stroke results.
- Other heart disease — People with coronary heart disease or heart failure have a higher risk of stroke than those with hearts that work normally. Dilated cardiomyopathy (an enlarged heart), heart valve disease and some types of congenital heart defects also raise the risk of stroke.
- Sickle cell disease (also called sickle cell anemia) — This is a genetic disorder that mainly affects African-American and Hispanic children. “Sickled” red blood cells are less able to carry oxygen to the body’s tissues and organs. These cells also tend to stick to blood vessel walls, which can block arteries to the brain and cause a stroke.
- High blood cholesterol — People with high blood cholesterol have an increased risk for stroke. Also, it appears that low HDL (“good”) cholesterol is a risk factor for stroke in men, but more data are needed to verify its effect in women.
- Poor diet — Diets high in saturated fat, trans fat and cholesterol can raise blood cholesterol levels. Diets high in sodium (salt) can contribute to increased blood pressure. Diets with excess calories can contribute to obesity. Also, a diet containing five or more servings of fruits and vegetables per day may reduce the risk of stroke (PDF opens in new window).
- Physical inactivity and obesity — Being inactive, obese or both can increase your risk of high blood pressure, high blood cholesterol, diabetes, heart disease and stroke. So go on a brisk walk, take the stairs, and do whatever you can to make your life more active. Try to get a total of at least 30 minutes of activity on most or all days
What are other less well-documented risk factors?
- Geographic location — Strokes are more common in the southeastern United States than in other areas. These are the so-called “stroke belt” states.
- Socioeconomic factors — There’s some evidence that strokes are more common among low-income people than among more affluent people.
- Alcohol abuse — Alcohol abuse can lead to multiple medical complications, including stroke. For those who consume alcohol, a recommendation of no more than two drinks per day for men and no more than one drink per day for nonpregnant women best reflects the state of the science for alcohol and stroke risk.
- Drug abuse — Drug addiction is often a chronic relapsing disorder associated with a number of societal and health-related problems. Drugs that are abused, including cocaine, amphetamines and heroin, have been associated with an increased risk of stroke. Strokes caused by drug abuse are often seen in a younger population.
