Cholesterol, high - Causes of high cholesterol

Lots of different factors can contribute to high blood cholesterol, including diet, age, family history and ethnic group.

Lifestyle

Your lifestyle can increase your risk of developing high blood cholesterol. This includes:

An unhealthy diet. Some foods, such as liver, kidneys and eggs, contain cholesterol (known as dietary cholesterol). However, this has little effect on blood cholesterol and it is the amount of saturated fat in your diet which is more important. Read more information about preventing high cholesterol.
Lack of exercise or physical activity. This can increase your level of "bad cholesterol" (low-density lipoprotein, or LDL).
Obesity. If you are overweight, you are likely to have higher levels of LDL cholesterol and triglycerides, and a lower level of high-density lipoprotein (HDL).
Drinking excessive amounts of alcohol. Regularly drinking a lot of alcohol can increase your cholesterol and triglyceride levels.
Smoking. A chemical found in cigarettes called acrolein stops "good cholesterol" (HDL) from transporting fatty deposits to the liver, leading to narrowing of the arteries (atherosclerosis).

Underlying conditions

People with high blood pressure (hypertension) and diabetes often have high cholesterol. Some medical conditions can also cause raised levels of cholesterol. These include:

Treating the underlying condition can help to reduce cholesterol.

Other factors

There are a number of factors associated with high cholesterol that cannot be changed. Doctors refer to these as fixed factors and they include:

Family history of early heart disease or stroke. You are more likely to have high cholesterol if you have a close male relative (father or brother) aged under 55 or a female relative (mother or sister) aged under 65 who has had coronary heart disease or stroke.
A family history of a cholesterol-related condition, for example if a close relative, such as a parent, brother or sister, has familial hypercholesterolaemia (see below).
Age. The older you are, the greater the likelihood of your arteries narrowing (atherosclerosis).
Ethnic group. People who are of Indian, Pakistani, Bangladeshi or Sri Lankan descent have an increased risk of high blood cholesterol.

If you have a fixed risk factor (or a number of fixed risk factors) it's even more important to look at your lifestyle and any underlying conditions that you may have.

Genetics

Familial hypercholesterolaemia is the medical term for high cholesterol that runs in the family. It is not caused by an unhealthy lifestyle, but by genetics. About one in 500 people inherit the condition from a parent.

Cholesterol is not cleared properly from your bloodstream and living with higher levels of cholesterol produces early heart problems.

For more information, see the NICE guidance on familial hypercholesterolaemia.