The Silent Threat: Ten Common Causes of Stroke

Abnormal heart rhythms, like atrial fibrillation, affect how the blood moves through the heart and can raise your risk of stroke. According to the CDC, atrial fibrillation is responsible for one of every seven strokes.

Interestingly, studies show that strokes themselves can cause abnormal heart rhythms, which can put people who have had a stroke at risk of having another.

Studies indicate that diabetes can double a person's risk of having a stroke and that stroke causes approximately 20 percent of deaths of people with diabetes. Some studies also show that the risk increases the longer someone has diabetes, but even people with prediabetes are affected.

The most critical stroke risk factor over which people have some control is high blood pressure. High blood pressure or hypertension has a robust and direct relationship to stroke risk. People do not have to be officially diagnosed with hypertension; generally, the higher someone's blood pressure is, the higher their stroke risk.

Blood pressure has a more significant effect on hemorrhagic strokes, which occur when a weak blood vessel bursts and bleeds into the brain tissue.

Heart disease is the leading cause of death in the United States. It refers to multiple conditions that affect how the heart functions, including coronary artery disease (CAD), in which plaque builds up in the vessels that deliver blood to the heart, ultimately leading to a heart attack.

Studies show that CAD is prevalent in people who have had ischemic strokes, in which a clot or plaque blocks a blood vessel in the brain.

Multiple studies demonstrate that high cholesterol and stroke are correlated. High cholesterol is associated with dying from stroke, and prevention trials have shown that some statins—medications to lower cholesterol—can reduce stroke risk by as much as 40 percent.

The more aggressive the treatment, the more the stroke risk appears to fall.

Another modifiable stroke risk is smoking. Studies show this habit increases the risk of stroke and that quitting smoking rapidly reduces the risk, returning it nearly to that of a non-smoker after only two to four years.

Cigarette smoking damages the heart in multiple ways, nicotine raises blood pressure, and carbon monoxide reduces the amount of available oxygen in the blood. Even exposure to secondhand smoke can increase stroke risk.

Sickle cell disease is a group of inherited disorders that affect the shape of the hemoglobin in the blood. Instead of being shaped like a flat, flexible disc, hemoglobin is crescent-shaped and does not move through the blood vessels easily.

Research shows that 24 percent of people with sickle cell disease have as stoke by age 45, and it can even affect children younger than two, as the blood vessels in their brains are so delicate.

The relationship between obesity and stroke is complex. Obesity is a risk factor for stroke, but there is still debate about why. While obesity is related to hypertension and diabetes, not every person with obesity has these conditions.

One study indicates that stroke risk for people with obesity may depend on metabolic abnormalities that result from obesity more than obesity itself. In one part of the study, metabolically unhealthy people were defined as having an increased waist circumference with at least two of the following: decreased HDL, elevated nonfasting triglycerides, high blood pressure, use of blood pressure medications, a diabetes diagnosis, or increased non-fasting glucose. Interestingly, the results showed that people with obesity who were metabolically healthy had a similar stroke risk as those at a normal weight.

Physical activity is good for the body in many ways, and a lack of exercise can have many adverse effects, including an increased risk of stroke. People who are more physically active have a lower risk of stroke and stroke mortality; in other words, if they do have a stroke, they are more likely to survive it.

This may be because exercise lowers blood pressure, helps maintain a healthy body weight, and can help reduce the effects of diabetes.

Both alcohol and drug use increase stroke risk. Studies show that while light to moderate drinking can be protective against an ischemic stroke, and drinking any amount of alcohol increases the risk of hemorrhagic stroke. Illicit drugs more commonly linked to stroke include stimulants like cocaine and amphetamine.