How High Cholesterol Levels Increase Stroke Risk

High cholesterol can increase your risk of having a stroke. This waxy substance contributes to the buildup of deposits, known as plaques, within blood vessels. Plaques can accumulate in the coronary arteries, which supply oxygen to the heart, and in the carotid arteries, which supply oxygen to the brain. A stroke occurs when a blockage prevents blood from reaching the brain.

This article explores the role of cholesterol in stroke and how you can reduce your risk of having a stroke.

Can High Cholesterol Cause a Stroke?

The connection between cholesterol and stroke is complicated because their relationship varies based on the type of stroke and the type of cholesterol involved.

Types of Stroke

There are two major types of stroke. The most common type of stroke, ischemic stroke, is caused by the blockage of blood flow. The risk factors for ischemic strokes, including high cholesterol, are the same as those coronary heart disease.

The other major type of stroke, hemorrhagic stroke, is caused by the rupture of a blood vessel, which bleeds into the brain. Elevated cholesterol is not associated with a high risk of this type of stroke.

Types of Cholesterol

Another significant factor: Not all cholesterol is the same. Different types of cholesterol can have very different effects on the body.

• Low-density lipoprotein (LDL) is the "bad cholesterol" in terms of its potential for harming the heart and brain. It is a major contributor to arterial plaque development. Levels of LDL cholesterol higher than 130 milligrams per deciliter (mg/dL) are linked to an increased risk for ischemic stroke.
• High-density lipoprotein (HDL) is the "good cholesterol." HDL levels higher than 35 mg/dL protect against ischemic stroke by helping ferry LDL to the liver and out of the bloodstream and by helping stabilize existing plaques.

Higher levels of HDL continue to add protection, with the greatest benefits conferred by HDL levels over 60 mg/dL, while HDL levels below 35 mg/dL are associated with higher stroke risk.

What Causes High Cholesterol?

High cholesterol is caused by certain diet and lifestyle factors. These typically include:

• Eating a lot of fatty or fried foods
• A sedentary lifestyle
• Smoking
• Drinking excessive amounts of alcohol
• Being overweight or obese

What Are Cholesterol Levels?

Your healthcare provider can measure your cholesterol levels with standard lipid blood tests. These tests can tell you how much of each type of cholesterol you have in your blood, as well as your total cholesterol. Low, average, and high numbers are as follows:

Because HDL is considered "good" cholesterol, optimal ranges are higher and concerning ranges are lower.

Current guidelines set similar cholesterol goals for reducing the risk of stroke and the risk of coronary heart disease. These guidelines generally recommend that people without existing heart disease who do not smoke and have no other heart disease risk factors (such as diabetes, high blood pressure, obesity, family history of heart disease) should maintain a total cholesterol level of less than 240 mg/dL, with LDL below 130 mg/dL and HDL above 40 mg/dL.

People with cardiovascular risk factors are advised to aim for even better cholesterol levels to better protect against heart disease and stroke. These individuals should maintain a total cholesterol level below 200 mg/dL, with LDL below 100 mg/dL, and HDL above 60 mg/dL.

What Increases Your Risk of Stroke?

High cholesterol is just one of a few things that can increase your risk of having a stroke. Other risk factors include:

• High blood pressure
• Heart disease
• Diabetes
• Being overweight or obese
• Smoking and alcohol use
• Poor diet and sedentary lifestyle
• Older age
• A family history of stroke
• Females have a higher lifetime risk of stroke
• Use of certain medications such as hormonal birth control or blood thinners
• Being of African American, Indigenous American, or Hispanic origin
• Arteriovenous malformations (AVMs), poorly formed veins and arteries in the brain that can rupture
• Medical conditions such as bleeding disorders and sleep apnea

How to Lower High Cholesterol to Reduce Stroke Risk

There are a number of changes you can make to your lifestyle than can help reduce your cholesterol levels and your risk of stroke. These include:

Change Your Diet

Eating a healthy diet is one of the best ways to reduce high cholesterol and lower your risk of stroke. Choose healthier fats and limit your intake of total fat and saturated fat. Avoid foods that are high in cholesterol.

Eat foods that are high in fiber and increase your intake of fruits, vegetables, and other plant-based foods such as whole grains, beans, and legumes. Eating fish that are high in omega-3 fatty acids can help raise your HDL levels. Avoid foods that are high in sodium and limit your consumption of alcohol.

Exercise Regularly

Exercise can help improve your cholesterol levels. Talk to your healthcare provider about starting an exercise program. Ideally, you should be getting around 30 minutes of exercise at least five times a week.

Quit Smoking

Studies have found that smokers have higher LDL cholesterol and triglyceride levels, and lower HDL levels. There is evidence that quitting smoking can help improve your blood cholesterol levels.

Maintain a Healthy Weight

Maintaining a healthy weight can help you keep your cholesterol levels in check. If you are overweight or obese, talk to your healthcare provider about starting a diet and exercise program.

Cholesterol-Lowering Medications and Stroke Risk

Medications used to lower cholesterol levels—in particular, the class of drugs known as statins—have been shown to lower the risk of having a stroke and may reduce the severity of a stroke, if one occurs. By reducing levels of LDL, statins and other cholesterol-lowering drugs help prevent plaque formation, which prevents stroke and heart disease.

In fact, statins have even been shown to reduce stroke risk in patients with normal cholesterol levels.

Statins can:

• Prevent plaques from forming
• Help stabilize existing plaque deposits
• Help make plaques less fatty and more fibrous, making them more resistant to rupture
  
• Reduce inflammation and help prevent clots from forming

Large research studies have drawn clear ties between the use of statins and reduced stroke risk. One meta-analysis (a study that reanalyzes the results of several other studies) found that statin use reduces stroke risk by 21% and that every 10% reduction in LDL levels resulted in a 15.6% reduction in stroke risk.

Studies of specific statins have shown even more striking results. Several studies have found that while statins offer a general reduction in stroke risk, the greatest benefit is seen in those who have not had a prior stroke. Though statins confer benefits to those who have already had at least one stroke or mini-stroke, the impact is weaker.

Other cholesterol-lowering medications have not matched the record of the statins. However, some small studies have shown protective effects, particularly by helping raise the level of HDL cholesterol. One study of Lopid (gemfibrozil), for example, showed the use of Lopid reduced the risk of stroke by 31% with the greatest benefits seen in patients with low initial levels of HDL.

Summary

High cholesterol can increase your risk of having a stroke. Lipid blood tests can tell you if your blood contains too much LDL cholesterol, triglycerides, and total cholesterol. HDL cholesterol is considered "good" cholesterol; your blood test can also tell you if your HDL cholesterol is ideal or too low.

Some of the risk factors for stroke can't be controlled, such as older age and genetics. You can lower your risk, however, by making certain lifestyle changes such as adopting a healthy diet and exercising 30 minutes a day five days a week. If your cholesterol levels are dangerously high, ask your healthcare provider about cholesterol-lowering medications.