Lipids or fats are found in our blood stream. There are different kinds of lipids that affect stroke risk. We will begin with cholesterol.

Cholesterol is made in the liver and is found in certain foods. While it is essential for the smooth working of the body, too much cholesterol can lead to furring up of the blood vessel walls making them more brittle and increasing the likelihood of blockages. Therefore, making sure cholesterol levels do not get too high can reduce risk of cardiovascular problems, including having a stroke. Managing cholesterol is especially important for people who have already had a stroke, to reduce the risk of having another stroke.

Gender, age, general health and a family history of high cholesterol can affect your cholesterol levels. But for most people, high cholesterol is caused by eating food containing too much saturated fat (for example in beef or cheese) and not enough food containing unsaturated fats (such as nuts and avocados). Being overweight, being less active, drinking too much alcohol and smoking can all contribute to high cholesterol levels.

What is a healthy level of cholesterol?¹

• Total cholesterol levels should be below 5.00mmol/L, with non-HDL (LDL) levels below 4.00mmol/L.
• Levels of HDL cholesterol should be above 1.0mmol/L for men or above 1.2mmol/L for women.

Cholesterol and stroke

Most research suggests that there is a direct link between cholesterol levels and stroke risk. High levels of LDL cholesterol (bad cholesterol) raises stroke risk, while HDL cholesterol (good cholesterol) may be beneficial because it helps remove excess cholesterol from the system.

High cholesterol may be treated with medications like statins or ezetimibe to keep LDL cholesterol levels under 1.8 mmol/L, to reduce risk of cardiovascular events, especially for stroke survivors^2,3.

Haemorrhagic stroke is more prevalent at lower cholesterol levels, while high cholesterol seems to raise the risk of certain types of stroke more than others^4,5.

Some research suggests that having high blood pressure as well as high levels of cholesterol increases stroke risk further⁶.

Other lipids and stroke

Triglycerides are another type of fat found in the blood stream which thought to increase the risk of stroke⁷. Triglycerides are made in our liver but high levels of triglycerides are related to diets with sugary drinks and snacks for example.

High levels of lipoprotein (a) increase the risk of stroke and appear to be an inherited or a genetic condition. It can also increase the risk of the thickening and hardening of the walls of arteries and it may trigger blockage of the arteries and cause clots. The levels of lipoprotein (a) vary widely between people, but there is a two to threefold higher concentration in people of African descent than in other populations. Research is ongoing for treatments.

Testing for lipids

Testing for cholesterol and triglycerides can be done as a preventative measure and after someone has had a stroke to reduce the chance of them having a second stroke.

Lipoprotein (a) levels in our blood stream can be measured but few countries screen for this lipid⁸.

Cholesterol and stroke: Key points

High levels of lipids including cholesterol can increase the risk for stroke. If cholesterol levels cannot be controlled through changes in lifestyle such as diet low in saturated fats such as nuts and avocados, it is usually treated with statins. In several trails statins were shown to reduce stroke risk by between 11% and 40% and higher doses appear to reduce the risk more⁹. Similarly, maintaining a healthy weight is associated with lower cholesterol levels. People who are overweight or who have obesity may only need to lose 5 to 10% of their starting weight to reduce their “bad cholesterol” and increase their “good cholesterol”¹⁰.