What Causes a Stroke? Top 10 Risk Factors

Of the top risk factors for what causes a stroke, having high blood pressure readings takes the prize.

what causes a stroke

A recent study has found that patients who stopped taking statins three to six months after being discharged following a stroke ran a much higher risk of having a second stroke, as well as a substantially higher risk of dying from other causes.

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Hypertension—high blood pressure readings—is dangerous for your brain, especially in terms of stroke risk. (See “New Hypertension Guidelines: Re-evaluating Blood Pressure Standards.”) In fact, of the top risk factors for what causes a stroke, Hypertension is the most powerful, according to results from the very large INTERSTROKE study published in the Lancet. Strokes, the equivalent of heart attacks in the brain and sometimes called “brain attacks,” are the third-leading cause of death worldwide, the fourth-leading cause of death in the U.S., and a leading cause of serious, long-term disability.

What Is a Stroke?

Strokes occur when an artery that supplies blood to the brain leaks, bursts, or is blocked by a blood clot. Within an hour, the nerve cells in that area of the brain become damaged and die. As a result, the part of the body controlled by the damaged area of the brain cannot work properly. The reason high blood pressure readings and stroke risk are so closely linked is twofold. Over time, hypertension leads to atherosclerosis and hardening of the arteries which can cause blockages in small blood vessels in the brain. It can also lead to a weakening of the brain’s blood vessels, which may cause them to balloon and burst.


Ischemic strokes are the most common type, accounting for about 85 percent of all strokes, according to the National Stroke Association (NSA). Ischemic strokes occur when a blood clot blocks a cerebral artery transporting oxygen-rich blood to your brain. Without adequate blood flow, the brain cells and tissue in the area supplied by the artery begin to die. As a result, you lose functions such as muscle control or cognition that are controlled by the affected area of the brain.

Another type of stroke, hemorrhagic stroke, occurs when a cerebral blood vessel ruptures, spilling blood into and around the brain and causing pressure that damages brain cells and tissue. Although they comprise only about 15 percent of all strokes, hemorrhagic strokes are responsible for about four out of every 10 stroke deaths, the NSA notes.

Top 10 Causes of Stroke

In the INTERSTROKE study, which was the first large study of its kind, Dr. Martin J. O’Donnell of McMaster University and colleagues estimated that of the 10 risk factors collectively responsible for 90 percent of all brain-damaging strokes, hypertension is number one.[1] The INTERSTROKE investigators compared 3,000 patients with a first stroke to 3,000 controls from 22 countries, including people from low and middle income countries. They identified 10 primary causes of stroke.

  1. History of hypertension or blood pressure readings >160/90 (51.8 percent)
  2. Low regular physical activity (28.5 percent)
  3. Elevated waist-to-hip ratio (abdominal obesity) (26.5 percent)
  4. Blood lipid level (ratio of ApoB to ApoA1) (24.9 percent)
  5. Current smoking (18.9 percent)
  6. Poor diet (18.8 percent)
  7. Psychological causes—depression (5.2 percent) and stress (4.6 percent)
  8. Cardiac causes (history of heart attack, abnormal rhythms, or valve disease) 6.7 percent
  9. Diabetes mellitus (5.0 percent)
  10. Alcohol intake (more than 30 drinks per month) (3.8 percent)

Hypertension Ranks #1 Among the Top 10 Causes of Stroke

The most important message from the study, according to O’Donnell, is the relation of high blood pressure readings to stroke risk. Don’t wait until you have symptoms of a stroke, or suffer permanent disabilities, such as paralysis or memory loss, to do something about your risk factors. In addition to urging blood pressure reduction, he highly recommended managing the other causes of stroke such as quitting smoking, losing weight, getting active, and eating well—”everything that your mom told you to do,” he said.

High Blood Pressure and Stroke Risk Can Be Managed with Natural and Integrative Therapies

Since even pre-hypertension (blood pressure readings of 120-139 over 80-89) has been found to increase your risk of having a stroke by 55 percent compared to adults with normal blood pressure, you cannot afford not to get your blood pressure under control.[2] The good news is that high blood pressure and stroke risk can be managed with natural and integrative therapies. And every little drop in your blood pressure readings counts: your risk of a stroke drops by a staggering 36 to 41 percent for every 10 points you lower your systolic blood pressure.[3]

How to Monitor Your Blood Pressure Readings

You can record your blood pressure readings at home using our free resources:

Supplements That Help Lower Blood Pressure

In addition to natural lifestyle therapies focusing on diet changes, exercise, and stress reduction, supplements like magnesium, fish oil, and coenzyme Q10 are excellent evidence-based integrative therapies that can help lower your high blood pressure and stroke risk even more. You can learn about these and other natural treatments for reducing your high blood pressure readings by clicking here.

For related reading, check out these posts:

This article was originally published in 2013 and is regularly updated.

[1] Lancet, 376 (9735), 112-23.
[2] Neurology. 2011 Oct 4;77(14):1330-7.
[3] Vasc Health Risk Manag. 2012;8:437-42.


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UHN Staff

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