There is good evidence that if you have high cholesterol or another lipid disorder you have a greater chance of getting heart disease. This is because your risk of getting atherosclerosis (where the arteries become narrow) is also increased.
If you have atherosclerosis, fatty deposits can build up inside your blood vessels, which increases your risk of having a heart attack or a stroke. The more bad cholesterol (LDL cholesterol) you have in your blood and the less good cholesterol (HDL cholesterol) you have, the higher your risk.
Many things besides the level of lipids in your blood affect whether or not you get heart disease. For example, having high blood pressure, smoking, being overweight, and not exercising can all increase your risk of getting heart disease. These are called risk factors.
When your doctor decides whether you should be treated for high cholesterol, he or she also looks at what other risk factors you have. Only when all these things have been considered can he or she estimate whether your chances of having a heart attack or a stroke are raised and whether you need treatment.
If you have high cholesterol and already have heart disease
The people at the greatest risk of having a heart attack or a stroke are those who already have signs of heart disease. So if you have angina (a pain in your chest that you get when you exercise or do something strenuous) or if you've already had a heart attack or a stroke, your chances of having another are higher than average. You'll probably need treatment to reduce your cholesterol.
Doctors in the UK have been given guidelines on using drugs called statins to reduce cholesterol. These guidelines say that if you already have heart disease (for example, you've had a heart attack or a stroke) then you should be treated with a drug called a statin. To learn more, see Statins for people with heart disease.
If you have high cholesterol and don't have heart disease
If you don't already have heart disease, it's more complicated to work out whether or not you need treatment for high cholesterol. It depends on what other risk factors you have.
Here are the other risk factors that mean you have a higher chance of having a heart attack or a stroke:
Someone in your family had heart disease early. Early means that your father or uncle had a heart attack or died suddenly from heart disease before they were 55 or your mother or another female relative had a heart attack before they were 65
You have high blood pressure (sometimes called hypertension)
You have diabetes
You are a man over 45
You are a woman over 55
You are a woman who had the menopause early
Your total cholesterol to HDL ratio is 6 or more. (For more information, see How doctors diagnose high cholesterol.)
You already have atherosclerosis (narrowing of the arteries).
Doctors can work out your risk of having a heart attack or a stroke in the next 10 years. They do this using the results of your cholesterol test and information about your other risk factors. Your doctor may say you have a low risk, medium risk, or high risk of heart disease.