What causes high cholesterol?

People are often surprised to find out they have high cholesterol or triglycerides, but there are many things that can raise your blood fats. Your lifestyle, your genes and your overall health can all have an affect, and these can all add up.

The causes of high cholesterol often overlap with the risk factors for diseases of the heart and blood vessels such as hearts attacks and strokes (known together as cardiovascular disease or CVD). The good news is, the steps you take to lower your cholesterol can also lower your risk of these diseases.

Your lifestyle

A number of things that you can change can lead to high cholesterol.  

Your age, gender and family background

Other things you can't change can mean you’re more likely to develop high cholesterol and heart disease.

  • Your age. Cholesterol and triglyceride levels naturally rise throughout adult life and reach a peak in our sixties and seventies. This could be partly due to changes in weight, activity levels and lifestyles as we get older. The older your are, the greater the risk of diseases. 
  • Your ethnic background. For example, people from South Asian and sub-Saharan African origin have a higher risk of diseases of the heart and blood vessels. 
  • Being male. Men are more at risk of heart disease than women. 
  • Menopause. The hormone oestrogen has a protective effect, keeping cholesterol levels down. Oestrogen levels fall when you reach menopause and cholesterol can rise.  
  • Your family history. You are at higher risk if you have a close family member, such as a parent or sibling, who has had high cholesterol or CVD, such as a heart attack or stroke. 

Your genes 

High cholesterol can be caused by genetic conditions that are passed down through families. Familial hypercholesterolaemia (FH) is one of the most common inherited cholesterol conditions. Some are very rare. 

See the genetic cholesterol conditions

Your health and wellbeing

Your overall health can affect your blood fats or your risk of heart disease. Health professionals might refer to some of these causes as ‘secondary causes’ of high cholesterol. 

Medicines

Some medicines can affect the amount of cholesterol and triglycerides in your blood. For example: 

  • diuretics
  • corticosteroids
  • immunosuppressants
  • anti-retroviral drugs
  • retinoids
  • oral oestrogen
  • beta-blockers
  • antidepressants
  • anticonvulsants.

Some raise blood fats only a little, while others raise them significantly. To see whether any medicines you're taking could have an effect, have a look at the product information leaflet which comes with them.

Don’t worry or stop taking these medicines as your doctor will have been aware of the effects when they prescribed them. They will regularly review how you're getting on and adjust your treatment if needed.

Menopause

Menopause is when the ovaries stop producing the hormone oestrogen and periods stop. Because of the change in hormones, some women gain weight and cholesterol levels rise.

  • LDL cholesterol can rise.
  • HDL cholesterol often rises.
  • The balance of HDL cholesterol to non-HDL cholesterol may become less healthy.

The rise in cholesterol means women have a higher risk of heart attacks and other disease of the heart and blood vessels after menopause than before, so it’s important to get blood fats and any other health problems under control. You can also speak to your GP or a menopause specialist during the lead up to the menopause (known as perimenopause) or after the menopause. 

What else can raise your triglycerides?

Find out

Health problems that are linked to raised cholesterol

If a cholesterol test shows you have high cholesterol your doctor will try to find out what’s causing it. If you have one of these medical conditions, it’s important to have treatment to bring it under control.

Underactive thyroid gland (hypothyroidism)

The thyroid gland is a gland in the neck. It produces a hormone called thyroxine which is needed to keep your body running. A lack of thyroxine slows down your metabolism, which is how the body changes what you eat and drink into energy.

Having low thyroxine is known as an underactive thyroid, hypothyroidism, myxoedema or Hashimoto's disease. It's quite common, especially in women between the ages of 40 and 50.

Low thyroxine can raise triglycerides but the main effect is on cholesterol. Luckily, it's easy to diagnose and treat. Once treated, your cholesterol and triglyceride levels should return to their usual levels within a few months.

A fall in thyroxine can happen very slowly so many people don't notice any signs or symptoms. There are symptoms that can develop over time, which can appear similar to other conditions: 

  • tiredness
  • lack of energy
  • weight gain
  • slow movements, thought and speech
  • pins and needles
  • breathlessness
  • dizziness
  • palpitations
  • hair loss, especially in the outer third of the eyebrows
  • dry skin.

Growth hormone deficiency

Growth hormone deficiency (GHD) is a rare condition where the pituitary gland in the brain doesn't make enough growth hormone. GHD can be present from birth (congenital) but can start later in life due to infection, a pituitary tumour or a brain injury, for example. It can also be idiopathic which means there is no known cause.

In adults, GHD can have a number of symptoms including:

  • low energy
  • loss of muscle strength
  • osteoporosis (bone weakening)
  • changes to your blood fats such as raised cholesterol and triglycerides.

GHD is treated with daily injections of a synthetic hormone called recombinant human growth hormone. This will help to improve cholesterol and triglyceride levels, and you should have them monitored regularly.

Kidney problems

We each have two kidneys. Their role is to filter out waste products from the blood which are then removed from the body in the urine.

Chronic Kidney Disease
This is the name for a gradual decline in kidney function. People with CKD often have raised LDL cholesterol and triglycerides and lower HDL cholesterol. It’s common to have diseases of the heart and blood vessels too, so statins and other treatments to lower cholesterol are recommended.

Nephrotic syndrome 
This happens when our kidneys become ‘leaky’ and proteins can leak into the urine. People with nephrotic syndrome often have raised levels of cholesterol and triglycerides.

Gout 

This is a kind of arthritis caused by too much uric acid in the blood which forms crystals between the joints. These crystals cause extreme tenderness, swelling and pain.

Gout is often associated with rich food such as offal, red meat, pâté, fortified wines and spirits, and too little fruit, vegetables and wholegrains. It's also linked to a rise in triglycerides in the blood.

Stress

Stress doesn’t directly raise your cholesterol but it can lead to unhealthy ways of coping which can raise your cholesterol and your risk of heart disease. For example, you might want to eat unhealthy food such as pizza and takeaways, drink more alcohol or smoke.

Stress can affect your health in other ways too. It can make other diseases worse, including disease of the heart and blood vessels, respiratory (breathing) problems and digestive problems. It can also affect your sleep and your mood.

A little bit of stress can be a good thing because it means you get things done. It’s when it gets too much that it can damage your health, whether it’s due to problems with work, home, relationships or money.

If you’re feeling stressed, take steps to look after your wellbeing:

  • get professional support from a counsellor
  • talk to friends, family or trusted colleagues
  • try relaxation exercises and techniques such as breathing exercises, meditation, yoga or massages
  • keep up with your hobbies and things you like to do, like reading a book, listening to music, having a hot bath or stroking a pet
  • be physically active – physical exercise is known to help lower stress.

You can also get support from other organisations

Learn how to lower your cholesterol

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What else can lead to heart disease? 

A number of other conditions can raise the risk of diseases of the heart and blood vessels. These include diabetes, high blood pressure, the metabolic syndrome, atrial fibrillation (a type of irregular heart beat), and long-term inflammatory disorders such as rheumatoid arthritis and systemic lupus erythematosus. Some of these can influence your blood fats too. 

Find out your risk 

Try the Heart age tool

There are a number of risk scores your doctor can use to work out your risk of having a serious event in the next ten years, such as a heart attack or stroke. You can also get an idea of your risk using the Heart age tool from the NHS.

Use the Heart age tool