Hypercholesterolaemia is a condition where your blood contains too much of a fatty substance called low-density lipoprotein, or LDL cholesterol. This common disorder affects millions of people worldwide and can silently increase the risk of serious health problems like heart attacks and strokes. While most people with high cholesterol feel perfectly healthy, understanding this condition and taking steps to manage it can make a significant difference in protecting your heart and blood vessels for years to come.

How Common Is Hypercholesterolaemia

Hypercholesterolaemia is remarkably widespread across the globe. About one out of every twenty people has this condition, making it one of the most common health concerns affecting adults today. In the United States alone, nearly one-third of all adults have high levels of LDL cholesterol in their blood.^[1] This means that if you were to gather a group of thirty people, roughly ten of them would likely have elevated cholesterol levels. The condition does not discriminate based on where you live, though lifestyle factors and diet patterns in different regions can influence how many people are affected.

The prevalence of hypercholesterolaemia has become a major public health concern because of its direct connection to cardiovascular disease. When you consider that atherosclerosis, which is caused by cholesterol buildup in the arteries, is the main cause of cardiovascular disease, and that cardiovascular disease causes more deaths globally than any other condition, the importance of addressing high cholesterol becomes clear.^[1] High cholesterol causes approximately 4.4 million deaths every year around the world.^[9]

Who Is More Likely to Develop High Cholesterol

Certain groups of people face a higher risk of developing hypercholesterolaemia than others. Age plays a significant role in this condition. People who are older than forty are more likely to have high LDL cholesterol levels.^[1] Gender also matters, as women, particularly those who have gone through menopause, face increased risk.^[1][3] The hormonal changes that occur during menopause can affect how the body processes cholesterol, leading to higher levels.

Ethnicity influences cholesterol levels as well. If you are of Asian Indian, Filipino, or Vietnamese descent, you are more likely to have elevated LDL cholesterol.^[1] Similarly, people of South Asian or sub-Saharan African origin face higher risk.^[3] These differences are likely due to a combination of genetic factors and dietary patterns common in these populations.

Children and young adults are not immune to high cholesterol either. The American Heart Association recommends that children get screened for high cholesterol once between ages nine and eleven. For children with a family history of high cholesterol, heart attack, or stroke, or those with conditions like diabetes or obesity, screening may start even earlier.^[2] After the initial childhood screening, the next cholesterol check is recommended for people between ages seventeen and twenty-one, and then regularly thereafter.^[2]

What Causes High Cholesterol

Understanding what causes hypercholesterolaemia helps you recognize how the condition develops. Your liver naturally produces all the cholesterol your body needs to build healthy cells, make hormones, and digest fatty foods.^[5] When you have hypercholesterolaemia, your body either makes too much cholesterol or cannot remove it effectively from your blood.

Genetics plays a powerful role in some cases. There is a form of hypercholesterolaemia called familial hypercholesterolaemia, which is inherited from your parents through genes.^[1] If you have this genetic condition, your body struggles to remove LDL cholesterol from your blood from birth, leading to very high levels throughout your life. This condition can run in families, meaning if one of your parents has it, you may have inherited it as well.

Diet is another major cause of high cholesterol. Eating foods that contain large amounts of saturated fats and trans fats contributes significantly to elevated cholesterol levels.^[1][3] Saturated fats are found primarily in red meat, full-fat dairy products like cheese and butter, and tropical oils such as coconut and palm oil.^[17] Trans fats, which were once common in margarines and commercially baked goods like cookies, crackers, and cakes, also raise cholesterol levels, though regulations have reduced their use in many countries.^[17]

Lifestyle factors beyond diet also contribute to hypercholesterolaemia. A lack of physical exercise means your body does not burn fats as efficiently, leading to higher cholesterol levels.^[1][3] Being overweight or obese directly raises LDL cholesterol because excess body fat affects how your body uses and removes cholesterol from the blood.^[5][21] Using tobacco products damages your blood vessels and contributes to cholesterol problems.^[1][3] Drinking too much alcohol can raise both cholesterol and triglyceride levels in your blood.^[21]

Several medical conditions can also cause or worsen hypercholesterolaemia. These include diabetes, hypothyroidism (an underactive thyroid gland), obstructive liver disease, chronic kidney failure, and nephrotic syndrome (a kidney disorder).^[1] Even some medications can raise cholesterol levels, including amiodarone, rosiglitazone, cyclosporine, and hydrochlorothiazide.^[1]

Risk Factors That Increase Your Chances

Beyond the direct causes of hypercholesterolaemia, several risk factors can increase your likelihood of developing the condition or experiencing its complications. High blood pressure is a significant risk factor because it damages the walls of your arteries, making it easier for cholesterol to build up.^[1][7] When you have both high blood pressure and high cholesterol together, the combination dramatically increases your risk of heart disease and stroke.

A family history of premature atherosclerotic heart disease is an important risk factor to consider. If you have close relatives who developed heart disease at a young age—before fifty-five in men or before sixty-five in women—you face higher risk yourself.^[1][7] This family connection suggests both genetic factors and possibly shared lifestyle habits that promote high cholesterol.

Diabetes is another crucial risk factor. When you have diabetes, high blood sugar damages your blood vessels and changes the way your body handles cholesterol, leading to a more dangerous pattern of lipids in your blood.^[1][7] Smoking cigarettes compounds the problem by damaging blood vessel walls, speeding up the hardening of arteries, and greatly increasing your risk for heart disease.^[7][21]

Having low levels of HDL cholesterol, often called “good cholesterol,” is also considered a risk factor. HDL cholesterol helps remove LDL cholesterol from your arteries and carries it back to the liver for disposal.^[1] When your HDL levels are too low, you lose this protective mechanism, making it easier for dangerous plaque to build up in your blood vessels.

Symptoms of Hypercholesterolaemia

In most cases, hypercholesterolaemia produces no symptoms at all. The vast majority of people with high cholesterol feel completely normal and have no physical signs that anything is wrong.^[1][2] This is what makes the condition particularly dangerous—it can silently damage your arteries for years before causing any noticeable problems. You cannot tell if your cholesterol is high just by how you feel.

However, in severe cases of hypercholesterolaemia, some visible signs may appear. You might develop cholesterol deposits on your eyelid skin, which appear as yellowish bumps or patches called xanthelasma.^[1] Similar deposits can form in other areas of connective tissue throughout your body, called xanthomas.^[1] These are accumulations of cholesterol that have built up to such high levels that they become visible under the skin.

Another physical sign that can occur with very high cholesterol is a corneal arcus, which is a gray or white arc visible around the edge of your cornea (the clear front part of your eye).^[1] This happens when cholesterol deposits form around the cornea. While these physical signs can indicate severe hypercholesterolaemia, most people never develop them, which is why blood testing remains the only reliable way to detect the condition.

Over time, if left untreated, the buildup of cholesterol in your arteries can eventually lead to symptoms related to cardiovascular disease. You might experience chest pain, also called angina, which occurs when not enough blood flows to your heart.^[5][8] However, by the time these symptoms appear, significant damage has already occurred to your blood vessels. In the worst cases, the first “symptom” of untreated high cholesterol is a heart attack or stroke.^[8]

How to Prevent High Cholesterol

The good news is that hypercholesterolaemia is largely preventable through healthy lifestyle choices. By making smart decisions about what you eat and how you live, you can significantly reduce your risk of developing high cholesterol in the first place, or help manage it if you already have it.

Diet plays the most important role in prevention. Since your body makes all the cholesterol it needs, experts recommend eating as little dietary cholesterol as possible.^[5] Dietary cholesterol comes from animal foods, including meat, seafood, poultry, eggs, and dairy products. Instead of foods high in saturated and trans fats, focus on eating whole grains, beans, fresh fruits, and vegetables, which are naturally high in fiber.^[21] Foods containing unsaturated fats, such as avocados, olive oil, and nuts, can actually help prevent and manage high cholesterol.^[21]

Specific dietary changes that help lower cholesterol include reducing saturated fats found in red meat and full-fat dairy products, eliminating trans fats often found in processed foods, eating foods rich in omega-3 fatty acids like salmon, mackerel, walnuts and flaxseeds, and increasing soluble fiber from oatmeal, kidney beans, and other legumes.^[17] These dietary changes can lower cholesterol levels by up to thirty percent in people who were previously eating an unhealthy diet.^[8]

Maintaining a healthy weight is another crucial prevention strategy. Being overweight or obese raises LDL cholesterol levels and increases your risk of heart disease.^[5][21] Even modest weight loss can help improve your cholesterol numbers. Talk with your doctor about what a healthy weight range is for you, and work together to develop a realistic food and fitness plan.

Regular physical activity helps prevent high cholesterol by helping you maintain a healthy weight and improving how your body processes fats. Adults should aim for at least two and a half hours of moderate-intensity exercise, such as brisk walking or bicycling, every week.^[21] Children and adolescents should get one hour of physical activity every day.^[21] You do not need to join a gym or run marathons—simple activities like taking the stairs instead of the elevator, parking farther away from store entrances, or doing jumping jacks during television commercials all add up.

If you smoke, quitting is essential. Smoking damages your blood vessels and greatly increases your risk for heart disease.^[21] It also lowers your HDL or “good” cholesterol while contributing to higher LDL levels. Quitting smoking provides immediate benefits to your cardiovascular system, and your risk of heart disease begins to drop within weeks of stopping.

Limiting alcohol consumption is also important for cholesterol prevention. Too much alcohol can raise both cholesterol and triglyceride levels in your blood.^[21] If you drink alcohol, men should have no more than two drinks per day, and women should have no more than one drink per day.

Regular check-ups with your healthcare provider are a vital part of prevention. Since high cholesterol has no symptoms, regular screening is the only way to catch it early. Many adults should have their cholesterol checked at least once every four to six years, though some people need testing more or less frequently depending on their risk factors.^[15] Talk with your healthcare team about the testing schedule that is right for you.

What Happens in Your Body

To understand hypercholesterolaemia, it helps to know what cholesterol is and how it functions in your body. Cholesterol is a waxy, fatty substance that your liver produces naturally.^[2][5] Your body needs cholesterol to build healthy cells, produce hormones that regulate many body functions, and digest fatty foods. Under normal circumstances, your liver makes exactly the right amount of cholesterol for these essential tasks.

When you have hypercholesterolaemia, the balance is disrupted. Your blood contains too much LDL cholesterol, which is often called “bad” cholesterol. When LDL cholesterol circulates through your bloodstream in excessive amounts, it begins to deposit itself along the walls of your arteries.^[5] These deposits combine with other substances to form a buildup called plaque. This process of plaque accumulation is known as atherosclerosis.^[1]

As plaque builds up over time, your arteries become narrower and less flexible. The narrowing restricts blood flow through these vital vessels, making it harder for oxygen-rich blood to reach your heart, brain, and other organs.^[2] Think of it like a pipe that becomes clogged with mineral deposits—the opening gets smaller and smaller, reducing the flow of water through it. In your arteries, this reduced flow means your organs do not get the blood and oxygen they need to function properly.

The situation becomes even more dangerous when a piece of plaque breaks loose from the artery wall. When this happens, your body tries to repair the damage by forming a blood clot at the site.^[2] This clot can partially or completely block blood flow through the artery. If the blockage occurs in an artery supplying your heart, it causes a heart attack. If it happens in an artery supplying your brain, it causes a stroke. Both situations are medical emergencies that can result in permanent damage or death.

Not all cholesterol is harmful. HDL cholesterol, often called “good” cholesterol, actually helps protect you against heart disease.^[5] HDL cholesterol works by collecting excess LDL cholesterol from your blood and artery walls and carrying it back to your liver, where it can be broken down and removed from your body. Having higher levels of HDL cholesterol can lower your risk of heart attack and stroke.

Another type of fat in your blood called triglycerides also plays a role in cardiovascular health. Triglycerides are fats that your body uses for energy.^[5] Your body makes triglycerides from excess calories that you eat but do not immediately need. When combined with high LDL cholesterol or low HDL cholesterol, elevated triglyceride levels can increase your risk of heart attack and stroke.^[5]

The process of atherosclerosis caused by high cholesterol typically develops slowly over many years or even decades. This is why high cholesterol that begins in childhood or early adulthood can lead to heart disease in middle age or later life. It also explains why early detection and treatment are so important—the sooner you address high cholesterol, the less time it has to damage your arteries.