Causes of high cholesterol

Many different factors can contribute to high blood cholesterol, including lifestyle factorslike smoking, an unhealthy diet and lack of exercise,as well as having an underlying condition, such as high blood pressure or diabetes.

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 (dietary cholesterol), butthis has little effect on blood cholesterol: it's the total amount of saturated fat in your diet that's more important to watch; read more 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're overweight, it's likely that you'll have higher levels of LDL cholesterol and triglycerides, and a lower level of high-density lipoprotein (HDL)
• drinkingexcessive amounts of alcohol regularly drinking large amountsof alcohol can increase your cholesterol and triglyceride levels
• smoking a chemical in cigarettes called acrolein stops "good cholesterol" (HDL) transporting cholesterol from 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 other health conditions that can also cause raised levels of cholesterol include:

• kidney disease
• liver disease
• an underactive thyroid gland (hypothyroidism)

Treating the underlying condition can help to reduce cholesterol.

Other factors

There are a number of factors associated with high cholesterol that can't be changed that increase your risk of having a heart attack or stroke . Doctors refer to these as "fixed factors".

They include:

• family history of early coronary heart disease (CHD) or stroke you're 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's had CHD or stroke
• a family history of a cholesterol-related condition for example, having a parent, brother or sister with familial hypercholesterolaemia
• age the older you are, the greater the likelihood of your arteries narrowing (atherosclerosis)
• ethnic group people of Indian, Pakistani, Bangladeshi and Sri Lankan descent are at increased risk of having a heart attack
• sex males are more likely to have heart attacks than females

If you have a fixed risk factor, or several fixed risk factors, it's even more important to look at your lifestyle and any underlying conditions you may have.

Familial hypercholesterolaemia

Familial hypercholesterolaemia is the medical term for high cholesterol that runs in families. It's caused by a gene alteration inherited from a parent, rather than an unhealthy lifestyle.

People with familial hypercholesterolaemia have raised cholesterol from birth, which can lead to the early development of heart problems, such as atherosclerosis and CHD.

In the UK, familial hypercholesterolaemia is thought to affect about 1 in 500 people, which means approximately 120,000 people are thought to be affected.

There's aone in two (50%) chance that a child orbrother or sister of someone with familial hypercholesterolaemia will also have the condition.

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