How High Cholesterol Levels Increase Your Stroke Risk

Cholesterol is a waxy substance that 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.

Man suffering a stroke at the gym
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Along with high blood pressure, diabetes, smoking, and obesity, high cholesterol levels are well-established as a risk factor for coronary heart disease for both men and women. Like these other factors, cholesterol is also a concern for stroke risk.

A stroke can result from the blockage of an artery that supplies oxygen to the brain. However, early research in this area has yielded mixed conclusions on the role of cholesterol in stroke.

A Complicated Story

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 complication: 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.

When a plaque ruptures, pieces of the plaque break free and are carried away in the bloodstream, where they may lodge in the arteries that supply oxygen to the brain. The ruptured plaque can trigger the blood to clot, which further increases the risk of blocked blood flow.

The Role of Cholesterol-Lowering Medications

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 have several effects:

  • 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.

Cholesterol Guidelines for Reducing Stroke Risk

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.

6 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. MedlinePlus. Cholesterol.

  2. Stone NJ, Robinson JG, Lichtenstein AH, et al. 2013 ACC/AHA guideline on the treatment of blood cholesterol to reduce atherosclerotic cardiovascular risk in adults: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Circulation. 2014;129(25 Suppl 2):S1-45. doi:10.1161/01.cir.0000437738.63853.7a

  3. Centers for Disease Control and Prevention. Types of stroke.

  4. Johns Hopkins Medicine. How statin drugs protect the heart.

  5. Zhou YH, Ye XF, Yu FF, et al. Lipid management in the prevention of stroke: a meta-analysis of fibrates for stroke preventionBMC Neurol. 2013;13:1. doi:10.1186/1471-2377-13-1

  6. MedlinePLus. Cholesterol levels: what you need to know.

By Heather M. Ross
Heather M. Ross, PhD, DNP, FAANP is a nurse practitioner and PhD in Human and Social Dimensions of Science and Technology.