Stroke risk factors: blood pressure, AFib, diabetes and what you can change

Signs of a stroke now? Call 911. Face drooping, arm weakness, slurred or strange speech: time to call 911. Every minute counts during a stroke (MedlinePlus). More in stroke warning signs.

What causes a stroke

A stroke happens when blood flow to part of the brain is blocked (ischemic stroke) or when a blood vessel in the brain bleeds (hemorrhagic stroke) (NHLBI). The NHLBI says about 87% of strokes are ischemic (NHLBI). The blockage is usually a piece of plaque or a blood clot. Plaque in the carotid arteries in the neck is a common cause (NHLBI).

A transient ischemic attack (TIA), or mini-stroke, is a blockage that breaks up before there is damage to the brain. It can turn into a full stroke (NHLBI), and having a TIA puts you at much higher risk of having a stroke (MedlinePlus).

The major risk factors

MedlinePlus lists these major risk factors (MedlinePlus):

• High blood pressure. This is the primary risk factor for a stroke.
• Diabetes.
• Heart diseases. Atrial fibrillation (AFib) and other heart diseases can cause blood clots that lead to stroke.
• Smoking. Smoking damages blood vessels and raises blood pressure.
• A personal or family history of stroke or TIA.
• Age. The risk of stroke goes up as you get older.
• Race and ethnicity. People who are African American or Hispanic have a higher risk.

Other factors linked to a higher risk are alcohol and illegal drug use, not enough physical activity, high cholesterol, an unhealthy diet and obesity (MedlinePlus).

More risk factors the NHLBI names

Ischemic and hemorrhagic strokes share many risk factors, such as high blood pressure, diabetes and high blood cholesterol. Blood clots can come from coronary heart disease, atrial fibrillation, heart valve disease and carotid artery disease, and bleeding can happen after taking blood thinners (NHLBI). The NHLBI also lists (NHLBI):

• Age: a stroke can happen at any age, but the risk is higher for babies under age 1 and for adults as they grow older.
• Family history and genes: the risk is higher if a parent or other family member has had a stroke, particularly at a younger age. People with blood type AB, which is not common, have a higher risk.
• Sex: at younger ages, men are more likely to have a stroke, but women tend to live longer, so their lifetime risk is higher. Birth control pills, hormone replacement therapy, pregnancy and the weeks after giving birth raise the risk in women. High blood pressure during pregnancy, such as from preeclampsia, raises the risk of stroke later in life.
• Other conditions: sleep apnea, kidney disease, migraine headaches, sickle cell disease, and viral infections or conditions such as lupus or rheumatoid arthritis that cause inflammation.
• Habits: drinking too much alcohol, sleeping too much (more than 9 hours) and using illegal drugs such as cocaine.
• Stress and isolation: anxiety, depression, high stress, working long hours and having little contact with others outside the home may raise the risk.
• Air pollution where you live or work.
• Race and ethnicity: in the United States, stroke occurs more often in Black, Alaska Native, American Indian and Hispanic adults than in white adults.

Which ones you can change

The NHLBI says factors you can control account for 82% to 90% of all strokes: high blood pressure, obesity, physical inactivity, poor diet and smoking (NHLBI).

MedlinePlus lists these heart-healthy changes to help prevent a first or a future stroke: eat a heart-healthy diet, aim for a healthy weight, manage stress, get regular physical activity, quit smoking, and manage your blood pressure and cholesterol. If these changes are not enough, you may need medicine to control your risk factors (MedlinePlus).

AFib and stroke

AFib can cause blood clots that lead to stroke (MedlinePlus). If you have been diagnosed with AFib, doctors use the CHA2DS2-VASc score to estimate stroke risk and decide about blood thinners; see CHA2DS2-VASc explained. What raises the chance of getting AFib in the first place is in AFib risk factors.

Warning signs: think FAST

Stroke symptoms often come on quickly: sudden numbness or weakness of the face, arm or leg (especially on one side), sudden confusion or trouble speaking or understanding speech, sudden trouble seeing in one or both eyes, sudden trouble walking, dizziness or loss of balance, or a sudden severe headache with no known cause (MedlinePlus). The FAST test (MedlinePlus):

• F, face: one side of the face droops when smiling
• A, arm: one arm drifts downward when both arms are raised
• S, speech: speech is slurred or strange
• T, time: time to call 911

The full list, including what to do while you wait, is in stroke warning signs.

Check your own risk factors

The stroke risk factor check walks through which risk factors apply to you. It does not give a percentage. For a 10-year estimate of heart attack, stroke and heart failure combined, ages 30 to 79, use the heart risk calculator (PREVENT).

Common questions

What is the biggest risk factor for stroke?

High blood pressure. MedlinePlus calls it the primary risk factor for a stroke (MedlinePlus), and it makes arteries in the brain more likely to break open (NHLBI).

Can young people have a stroke?

Yes. A stroke can happen at any age, though the risk goes up as adults get older (NHLBI).

Does a TIA raise my risk of stroke?

Yes. A TIA puts you at much higher risk of having a stroke (MedlinePlus). If a TIA is diagnosed in an emergency room, follow up as soon as possible with a primary care provider and a neurologist (NHLBI).