This information is for people who have had a stroke or transient ischemic attack (TIA or mini-stroke) or are at risk of having one.

How can high cholesterol cause a stroke?

Cholesterol is an important substance in our bodies. It plays a part in our digestive and hormonal systems but can be harmful if levels get too high. Cholesterol is a fatty substance, called a lipid, which is found naturally in your blood.

High cholesterol is very common. It’s thought about one in two adults in the UK have raised cholesterol levels. It’s important to check your cholesterol levels. If there’s too much cholesterol in your blood it can damage your blood vessels, which may cause heart disease and stroke.

But with the right treatment and support with a healthy lifestyle, high cholesterol can usually be treated effectively.

Where does cholesterol come from?

Your body produces most of the cholesterol it needs in the liver. We also consume cholesterol in our diets.

Your liver changes how it processes cholesterol if your diet is high in saturated fats. Excess cholesterol enters your bloodstream and can cause a build-up of fatty deposits in your arteries, which can become narrow and stiff. This is a process called atherosclerosis.

The damage to the artery wall can lead to a clot forming, which may travel to the brain and cause a stroke. You do not usually need to avoid eating foods that contain cholesterol, such as eggs or seafood. But you should try to reduce the amount of fat that you eat, especially saturated and trans fats.

What are the different types of cholesterol?

Cholesterol moves around the body by attaching itself to proteins in the blood. This combination of cholesterol and protein is called a lipoprotein. There are two types of cholesterol: ‘good’ cholesterol and ‘bad’ cholesterol. Each type has an important role and it’s important to have the right balance of both in your body.

• Good cholesterol – HDL (high density lipoprotein) takes cholesterol away from cells and back to the liver. The cholesterol is then destroyed. Because of this, HDL is known as good cholesterol. You should aim to increase your levels of HDL.
• Bad cholesterol – non-HDL or LDL (low density lipoprotein) moves cholesterol to where it’s needed in your cells. But if there is too much non-HDL cholesterol in your blood, it can end up as fatty deposits in your arteries. This will increase your risk of stroke. If you’ve been diagnosed with high cholesterol, it’s likely that your LDL is high.

As well as lifestyle factors, other risk factors, such as your gender, age, other health conditions and whether you have high cholesterol in your family, may make you more likely to have high cholesterol.

How is cholesterol measured?

Cholesterol levels are checked with one of the following types of blood test:

• A full lipid profile test: Some blood is taken from your arm with a needle. The blood is sent to a lab and you’ll usually get the results in a few days. For some tests you may be asked to not eat or drink anything for 12-14 hours before, although this isn’t very common.
• A finger prick test: A small drop of blood from your finger is placed on a strip of paper and tested in a machine. You’ll get the results straight away.

Ask your GP surgery or a pharmacist about getting your cholesterol checked. They’ll talk to you about which test is best for you.

What are normal levels of cholesterol?

Cholesterol is measured in mmol/L, which is the amount of cholesterol per litre of blood.

Generally, your total cholesterol level should be below 5mmol/L, and the level for non-HDL (bad cholesterol) should be below 4mmol/L. These levels are a guide for healthy adults.

However, the options for managing your cholesterol also depend on whether you have had a stroke or heart attack, and what your underlying risk factors are. If you’ve had a stroke or a heart attack, your doctor will work with you to try to reduce your cholesterol to a level which is safe and healthy for you.

National clinical guidelines for people who have already had a stroke suggest you should aim to get your non-HDL cholesterol levels to 2.6mmol/L or less (or your LDL to 2.0mmol/L or less), but your doctor should be able to give you individual advice on your own health and treatment.

How often should I check my cholesterol?

How often you check your cholesterol levels will depend on your age and if you have other health conditions. Your doctor will be able to tell you how often you should have your cholesterol checked, based on your individual situation.

If you’re on cholesterol-lowering medication, it’s important to get your cholesterol checked at least once a year.

You should contact your GP surgery for a cholesterol test if any of the following applies to you:

• You’re over 40.
• You’re overweight.
• You have a family history of stroke, high blood pressure or other medical conditions such as heart disease or diabetes.

If you’re aged between 40 and 74, live in England and do not have a pre-existing health condition, you should be offered an NHS Health Check every five years. It includes a cholesterol test. Contact your GP surgery if you think you may be eligible but have not been offered a check.

Your cholesterol results, along with factors like other health conditions, will help your health professional assess your risk of stroke and heart attack. You may hear this called a ‘QRISK score’. They will talk to you about things you can do to reduce your risk of a stroke or heart attack in the future.

Support

Our Stroke Support Helpline is for anyone affected by a stroke, including family, friends and carers. The Helpline can give you information and support on any aspect of stroke.

Call us on 0303 3033 100, from a textphone 18001 0303 3033 100 or email helpline@stroke.org.uk

Resources available

The information in this section can be accessed in the following formats.

• Download this information as a PDF or large print Word document.
• Order a printed copy from our Shop.
• To request a braille copy, email feedback@stroke.org.uk.