Middle-aged men with high cholesterol levels are at greater risk for a first heart attack than similar women are, Norwegian researchers report.
Cholesterol blood tests are done to help assess your risk of developing heart disease or stroke. If your risk is high then you will usually be advised to take a statin medicine to lower your cholesterol level. Lowering your cholesterol level reduces your risk, even if your cholesterol level is normal. Other factors that can reduce your risk include: not smoking, choosing healthy foods, a low salt intake, regular physical activity, keeping your weight and waist size down and drinking alcohol in moderation. Ensuring your blood pressure level is not raised (or taking medication to lower it if it is high) is also important.
What is cholesterol?
Cholesterol is a lipid (fat chemical) that is made in the cells in your body. Many different cells make cholesterol but cells in the liver make about a quarter of the total. Although many foods contain cholesterol, it is poorly absorbed by the gut into the body. Therefore, cholesterol that you eat in food has little effect on your body and blood cholesterol level. A certain amount of cholesterol is present in the bloodstream. You need some cholesterol to keep healthy. Cholesterol is carried in the blood as part of particles called lipoproteins. There are different types of lipoproteins, but the most relevant to cholesterol are:
- Low-density lipoproteins carrying cholesterol - LDL cholesterol. This is often referred to as bad cholesterol. This is the one mainly involved in forming atheroma. Atheroma is the main underlying cause of various cardiovascular diseases (see below). The majority of cholesterol in the blood is LDL cholesterol, but how much varies from person to person.
- High-density lipoproteins carrying cholesterol - HDL cholesterol. This is often referred to as good cholesterol. This may prevent atheroma forming.
What are atheroma and cardiovascular diseases?
Patches of atheroma are like small fatty lumps that develop within the inside lining of arteries (blood vessels). Atheroma is also known as atherosclerosis and hardening of the arteries. Patches of atheroma are often called plaques of atheroma.
Over months or years, patches of atheroma can become larger and thicker. So in time, a patch of atheroma can make an artery narrower. This can reduce the blood flow through the artery. For example, narrowing of the coronary (heart) arteries with atheroma is the cause of angina.
Sometimes, a blood clot (thrombosis) forms over a patch of atheroma and completely blocks the blood flow. Depending on the artery affected, this can cause a heart attack, a stroke, or other serious problems.
Cardiovascular diseases are diseases of the heart (cardiac muscle) or blood vessels (vasculature). However, in practice, when doctors use the term cardiovascular disease they usually mean diseases of the heart or blood vessels that are caused by atheroma.
In summary, cardiovascular diseases caused by atheroma include: angina, heart attack, stroke, transient ischaemic attack (TIA) - sometimes called mini-stroke - and peripheral vascular disease. In the UK, cardiovascular diseases are a major cause of poor health and the biggest cause of death.
Who should be treated to reduce their cardiovascular health risk?
Treatment to reduce the risk of developing a cardiovascular disease is usually offered to people with a high risk. That is:
- People with a risk assessment score of 20% or more. That is, if you have a 2 in 10 chance or more of developing a cardiovascular disease within the next 10 years.
- People with an existing cardiovascular disease (to lower the chance of it getting worse, or of developing a further disease).
- People with diabetes. If you have diabetes, the time that treatment is started to reduce cardiovascular risk depends on factors such as: your age, how long you have had diabetes, your blood pressure and if you have any complications of diabetes.
- People with certain kidney disorders.
The following people should also have medication to lower their cholesterol level, regardless of any calculated risk. The risk calculator may not necessarily take these people into account who have a high risk of developing atheroma:
- People with a total cholesterol (TC) to HDL ratio of 6 or more (TC/HDL = 6 or more).
- People with inherited lipid disorders.