Researchers estimate that 80 percent of strokes are preventable. Genetics and past health determine about 20 percent of collective stroke risk. That means the odds of changing your lifestyle work in your favor. But first, you have to know the risks.

“Knowledge is power,” says Dr. Natalia Rost, associate professor of neurology at Harvard Medical School and associate director of the Acute Stroke Service at Massachusetts General Hospital. “If you know that a particular risk factor is sabotaging your health and predisposing you to a higher risk of stroke, you can take steps to alleviate the effects of that risk.”

Nearly 800,000 Americans have strokes a year, and about 610,000 of them are first strokes. Unfortunately, 160,000 patients die a year of complications, making strokes the third-leading killer in the U.S. What is this killer of so many Americans?

“Brain Attacks”

Most experts would now like the public to think of strokes as “brain attacks.” Blood and oxygen delivery is disrupted on its way to the brain. The longer a brain is starved of nutrients and oxygen, the worse the outcome for the stroke survivor.

Ischemic strokes involve blood vessel blockages in the neck or head. These are the most frequent types of strokes, coming in at 80 percent of all occurrences. Brain cells die without blood flow and vital oxygen. There are three different types of clots – thrombosis, a clot in the neck or head’s blood vessel; stenosis, severe narrowing of an artery in or leading to the brain; and embolism, movement of a clot from one part of the body to the other.

Hemorrhagic stroke occurs with bleeding into the brain or spaces surrounding it.


Risk Factors
 
Risk factors are conditions and behaviors that occur more frequently in those at a higher risk of getting a disease. These are factors that cannot be changed with lifestyle or medical intervention.

• Age. Strokes occur in all age groups, although studies have shown that the risk of stroke doubles for each decade between 55 and 85 years of age. But don’t be fooled  -- strokes also occur in early childhood or adolescence.
• Gender. It used to be that more men than women had strokes, but women tended to die first. It was thought that men survived their first strokes because they live shorter lives. Therefore, their first strokes were at a younger, more robust age for recovery than is the case for women.

Unfortunately, recent studies have shown that strokes are a growing health threat for middle-aged women. The reasons are thought to be increasing rates of obesity – women’s waists have grown by an average of two inches in the past 10 years; vitamin D sulfate deficiency – lack of sun exposure may be an underlying cause of arterial plaque buildup, a risk factor for strokes; and the rising prevalence of high blood sugar.

• Ethnic group. Stroke is more common and deadly in African-Americans than in any other ethnic group in the U.S. It is twice as high as that of Caucasians. African Americans often have sickle-cell anemia, which causes a narrowing of the arteries and disrupts blood flow.
• Family history. Strokes seem to run in families. Some families have a genetic tendency for stroke risks such as diabetes and high blood pressure. One must keep in mind that there is a common lifestyle among family members that may contribute to this dynamic.

Now we will look at risk factors you can control to lessen your chances of stroke.  

1. Hypertension or high blood pressure. This factor increases stroke risks by two to four times before the age of 80. Some strategies that may help bring that blood pressure down is to lose weight and eat more vegetables and fruits – up to five servings a day to pump up potassium levels. Cut down on processed salt, and, for health’s sake, exercise. Medications can help when needed.
2. Cigarette smoking. Smoking will increase your chance of ischemic stroke by two and increase your chance of hemorrhagic stroke four times. Smoking has been linked to plaque buildup in the carotid artery. Blockage of this artery, which runs from the heart through the neck to the brain, is the main cause of stroke in Americans. Nicotine, found in cigarettes, raises your blood pressure -- inadvisable if you want to avoid strokes.
3. Diabetes. In terms of strokes, having diabetes is equal to taking 15 years off of your life. Diabetes causes devastating changes to the blood vessels in the body. If a person’s blood sugar were high at the time of the stroke, there is more brain damage. Hypertension, which is common in diabetics, increases stroke risk as well.
4. Heart disease. Many heart disorders create blood clots, such as enlargement of one of the heart’s chambers, a defective heart valve, irregular heartbeat or coronary artery disease. Clots can break loose from the heart tissue and travel through the arteries to the brain.
5. Physical inactivity and obesity. Hypertension, diabetes and heart disease are associated with a sedentary lifestyle. Research has shown that there is an ideal ratio of waist-to-hip circumference, and if it is exceeded, the risk of ischemic stroke rises by a factor of three.

And did you know that exercise is a stand-alone risk reducer? In a 2012 study, women who had three hours of exercise a week had a substantially lower risk of strokes than women who did not exercise.

6. Cholesterol imbalance. Excess low-density lipids (LDL), the bad kind of cholesterol, tends to build up against the walls of blood vessels. This leads to atherosclerosis, or plaque deposits blocking the vessels. This is a major cause of narrowing of the arteries and leads to heart attacks and strokes.

7. Atrial fibrillation (AFib). This heart defect affects 2.2 million people in the U.S. Atrial fibrillation, or AFib, is an irregular heartbeat often caused by an uncoordinated pumping action that takes place in the upper two chambers. This causes blood to collect and can potentially form a fatal blood clot. Underlying health conditions such as diabetes, sleep apnea and thyroid disease can cause AFib, so be sure to manage these conditions under the supervision of a doctor to minimize the risk of AFib.

Armed with this information and knowledge, you can minimize your own stroke risk, something that is vitally important if you already have “built-in” risk factors like family history or ethnic group.