Risk factors are things that can cause a stroke or make it more likely to happen. They are different for everyone.
You can change many of the common risk factors and lower your chance of stroke with some simple steps. Talk your doctor or pharmacist about these stroke risk factors:
- High blood pressure can damage the walls of blood vessels, and it can lead to heart problems. It can cause clots or plaques to break off and block an artery in the brain. High blood pressure is also the strongest risk factor for haemorrhagic stroke. Read more about high blood pressure
- Type 2 diabetes affects the body’s ability to absorb glucose (sugar), and can lead to fatty deposits or clots in blood vessels. Read more about type 2 diabetes
- Cholesterol can build up in plaques on the walls of arteries, narrowing the artery and leading to a clot. Read more about high cholesterol
- Atrial fibrillation, or irregular heartbeat, causes stagnant blood flow through the heart, and can cause a clot that then goes to the brain. Read more about atrial fibrillation
- Inactivity or lack of exercise increases your risk of type 2 diabetes, being an unhealthy weight, high blood pressure and high blood cholesterol. Read more about physical activity
- Diet can affect blood pressure, type 2 diabetes, cholesterol, heart disease, kidney disease and some cancers. Read more about eating well
- Smoking doubles your risk of stroke by damaging blood vessel walls, increasing blood pressure, reducing oxygen in the blood, and making blood more likely to clot. Read more about smoking
- Alcohol can cause high blood pressure and atrial fibrillation. It can contribute to uncontrolled diabetes and being an unhealthy weight. Read more about alcohol
Other risk factors
There are other risk factors that you can talk to your doctor about. Find out what you can do to make a stroke less likely.
- Having had a stroke means you’re more likely to have another one.
- Older age makes a stroke more likely. Your doctor will consider your age with other risk factors.
- Being male means a higher stroke risk at nearly every age, even though women have their own risk factors like pregnancy, oral contraception and hormone replacement therapy (see below).
- Family history can mean a higher stroke risk. For example, high cholesterol can run in families.
- Heart conditions like a hole in the heart (patent foramen ovale, or PFO) or heart disease, can cause a clot to form and travel to the brain.
- Blood vessel problems make a bleed more likely. They include weak spots that balloon out (aneurysm), tangled arteries and veins (arteriovenous malformation, or AVM), or a ‘cavern’ made of tiny blood vessels (cavernous malformation, or cavernoma).
- Blood disorders can make clots more likely. These include essential thrombocytosis, polycythaemia vera, antiphospholipid syndrome, and sickle cell anaemia.
- Genetic disorders can mean a higher risk of specific types of stroke that runs in families. For example, CADASIL (strokes in small blood vessels), Ehlers-Danlos syndrome (arteries more likely to break), and fibromuscular dysplasia (damages walls of arteries in the neck).
- Autoimmune conditions can inflame the walls of blood vessels, making them narrower and more likely to clot.
- Infections, including bacterial heart infections and COVID-19, can cause clots.
- Medication including blood thinners, which reduce your chance of an ischaemic stroke or clot, can also mean a higher risk of a haemorrhagic stroke or bleed.
- Illegal drugs, such as amphetamine and cocaine, can increase your risk of stroke, especially bleeds.
- Trauma, such as an injury to the head or neck, can break blood vessels and cause a bleed or a clot.
- Pregnancy can increase blood pressure, especially with pre-eclampsia and eclampsia, and it can also cause gestational diabetes.
- Oral contraception, particularly pills containing a higher dose of oestrogen.
- Hormone replacement therapy, which is associated with a small increase in the risk of stroke.
- Migraine with aura, which can affect blood vessels and make a stroke more likely.
Sometimes, a cause can’t be found even after lots of tests. This is called a cryptogenic stroke. If the cause of your stroke is unknown, it’s important to talk with your doctor about what they have done to find the cause, and what you can do to reduce your risk of another stroke.
It's common to worry when a cause can't be found. Contact StrokeLine for advice and support.
For more on the possible ways a stroke can happen, see Types of stroke.
Some things increase the chances of having a stroke.
Some of these things you can’t do anything about.
Things you can’t do anything about
These are things like:
- getting older
- being a man – strokes happen to men more often than women
- someone in your family has had a stroke
- you have already had a stroke.
Things you can do
There are some things that you can do something about.
- high blood pressure
- problems with your heartbeat (atrial fibrillation)
- high cholesterol
- not eating right
- not getting enough exercise
- being overweight
- drinking too much alcohol.
Take action now
You can make it less likely you will have a stroke.
There are six things you can do right now:
- Talk to your doctor about blood pressure, blood cholesterol and diabetes.
- Exercise regularly.
- Lose weight and eat a healthy diet.
- Don’t drink too much alcohol.
- Quit smoking.
- Learn to recognise the warning signs of a stroke and act FAST.
The FAST test
The FAST test helps you remember the signs of stroke.
Stroke is always an emergency.
Call 000 immediately.
Get help FAST.
This can improve your chance of getting better.