Dyslipidaemia

Dyslipidaemia is a condition where the levels of fats in your blood are not in the healthy range, which can increase your risk of heart disease and stroke.

Table of contents

• What is dyslipidaemia
• Types of dyslipidaemia
• Causes and risk factors
• Symptoms and signs
• Diagnosis
• Complications
• Treatment
• Lifestyle changes

What is dyslipidaemia

Dyslipidaemia refers to abnormal levels of lipids in the bloodstream^[1]. Lipids are fats that include cholesterol and triglycerides, which are absorbed from food and carried throughout the body by special proteins called lipoproteins^[1].

Your blood contains three main types of lipids. Low-density lipoprotein (LDL) cholesterol is considered “bad” cholesterol because it can build up and form clumps or plaques in the walls of your arteries^[2]. High-density lipoprotein (HDL) cholesterol is the “good” cholesterol because it helps remove LDL from your blood^[2]. Triglycerides come from the calories you eat but don’t burn right away, and are stored in fat cells^[2].

An imbalance of any of these fats can lead to dyslipidaemia^[1]. This usually means your LDL levels or your triglycerides are too high, or it can mean your HDL levels are too low^[2]. Too much cholesterol, particularly borderline high levels of 200 to 239 milligrams per deciliter or high levels of 240 mg/dL and above, isn’t healthy because it can create blockages in your arteries where blood travels around your body^[3].

Dyslipidaemia is a well-established contributor to cardiovascular disease, which includes conditions like coronary artery disease, stroke, and heart failure^[7]. The global burden of dyslipidaemia is growing, contributing to approximately 4.4 million deaths annually worldwide^[7]. Over one-third of the world’s population is affected by elevated blood cholesterol^[7].

Types of dyslipidaemia

Dyslipidaemia is classified into two main types: primary and secondary^[1].

Primary dyslipidaemia is inherited and caused by genetic mutations that affect how the body processes lipids^[1]. Among the specific types of primary dyslipidaemia are familial combined hyperlipidaemia, familial hypercholesterolaemia, and polygenic hypercholesterolaemia^[2].

Familial combined hyperlipidaemia is the most common inherited cause of both high LDL cholesterol and high triglycerides. If you have this condition, you could develop these problems in your teens or twenties, and you’re at a higher risk for early coronary artery disease, which can lead to a heart attack^[2].

Secondary dyslipidaemia is acquired and develops from other causes^[1]. This means it develops from lifestyle factors or other medical conditions that alter lipid levels^[1]. Common causes include obesity, diabetes, hypothyroidism, alcoholism, and certain medications^[4].

You may hear the term hyperlipidaemia used interchangeably with dyslipidaemia, but that’s not entirely accurate. Hyperlipidaemia refers to high levels of LDL or triglycerides, while dyslipidaemia can refer to levels that are either higher or lower than the normal range for those blood fats^[2].

Causes and risk factors

Dyslipidaemia can result from genetic predispositions or lifestyle factors^[1]. Some causes include impaired lipoprotein synthesis, secretion, and clearance in the body^[1].

Secondary causes of dyslipidaemia include hypothyroidism and genetic predisposition^[9]. Triglyceride elevation may occur in association with diabetes mellitus, alcoholism, obesity, and hypothyroidism^[9].

High intake of foods containing unhealthy fats such as saturated fats and trans fats can contribute to high cholesterol. These are found in fatty meats and deli-style meats, butter, cream, ice cream, coconut oil, palm oil, and most deep-fried takeaway foods and commercially baked products like pies, biscuits, buns, and pastries^[22]. Low intake of foods containing healthy fats can also be a problem, as healthy fats tend to increase the good HDL cholesterol^[22].

Several risk factors increase the likelihood of developing dyslipidaemia. These include family history of dyslipidaemia, current cigarette smoking, diabetes mellitus, hypertension, obesity with a body mass index greater than 30 kg/m², atherosclerosis, family history of premature coronary artery disease, HIV infection, erectile dysfunction, chronic kidney disease, and chronic obstructive pulmonary disease^[6].

Symptoms and signs

Most people with high cholesterol feel perfectly well and often have no symptoms^[3]. Dyslipidaemia typically doesn’t cause noticeable symptoms in its early stages, which is why it’s often called a “silent” condition.

In more advanced cases, some people may develop clinical signs. These can include xanthelasmas, which are yellowish deposits on the eyelids, xanthomas, which are fatty deposits under the skin, and premature arcus cornealis, which is a grey or white ring around the cornea of the eye^[6].

Because dyslipidaemia often has no symptoms, it’s important to have your cholesterol levels checked regularly by your doctor through a blood test^[3].

Diagnosis

Diagnosis of dyslipidaemia relies on lipid profile tests, which measure plasma levels of total cholesterol, triglycerides, and individual lipoproteins^[1]. Your doctor can check your blood lipid levels with a simple blood test^[2].

The results of the test will include information about your total cholesterol, LDL (bad cholesterol), HDL (good cholesterol), and triglycerides^[3]. In general, you may not be able to have food or liquids other than water for around 9 to 12 hours before the test, though some cholesterol tests don’t require fasting^[14].

For people aged 45 years and over, you can have your cholesterol checked as part of a Heart Health Check. For Aboriginal and Torres Strait Islander peoples, cholesterol should be checked from age 18 years^[22]. The general recommendation is that total cholesterol and HDL cholesterol levels should be measured every five years beginning at age 20 in patients who do not have coronary heart disease or other atherosclerotic disease^[9].

In the United States, cholesterol levels are measured in milligrams per deciliter of blood. For adults 20 years of age and older, total cholesterol should be between 125 and 200 mg/dL^[3]. A total cholesterol level of under 200 mg/dL is considered desirable, 200 to 239 mg/dL is borderline high, and 240 mg/dL and above is high^[5].

For LDL cholesterol, everyone regardless of age or gender should keep this number under 100 mg/dL. For HDL cholesterol, men 20 and older should keep this level above 40 mg/dL, and women 20 and older should aim for 50 mg/dL or higher^[3].

Complications

Dyslipidaemia poses a significant risk factor for cardiovascular diseases^[1]. High LDL and triglyceride levels put you at a higher risk for heart attack and stroke^[2]. Low levels of HDL cholesterol are also linked to higher heart disease risks^[2].

Elevated levels of LDL cholesterol, often referred to as “bad cholesterol,” significantly raise the risk of atherosclerotic cardiovascular events such as coronary artery disease, stroke, and heart failure^[7]. Atherosclerosis occurs when cholesterol builds up and forms plaques in the walls of arteries, making it harder for blood to flow through^[2].

As long as high cholesterol is untreated, plaque continues to accumulate inside blood vessels. This can lead to a heart attack or stroke because your blood has a hard time getting through your blood vessels, which deprives your brain and heart of the nutrients and oxygen they need to function^[3]. Cardiovascular disease is the leading cause of death in Americans^[3].

The greater the lifetime exposure to high LDL cholesterol levels, as seen with an aging population, the greater the risk of adverse outcomes^[7]. Today, one in three heart attacks or strokes can be directly attributed to high LDL cholesterol^[7].

Treatment

Treatment strategies work to mitigate risks by targeting specific lipid abnormalities, emphasizing lifestyle modifications, and considering individual health conditions to personalize care^[1]. Given the complex nature of dyslipidaemia management, a multidisciplinary approach is essential for comprehensive patient care^[1].

For primary prevention of coronary heart disease, the treatment goal is to achieve an LDL cholesterol level of less than 160 mg/dL in patients with only one risk factor. The target LDL level in patients with two or more risk factors is 130 mg/dL or less. For patients with documented coronary heart disease, the LDL cholesterol level should be reduced to less than 100 mg/dL^[9].

Management of dyslipidaemia through lowering of LDL cholesterol levels has proven effective in reducing the incidence of both initial and recurrent cardiovascular events^[7]. Doctors consider other factors in addition to your cholesterol numbers when they make treatment decisions^[3].

Medications can help improve your cholesterol levels. The most commonly used options for drug treatment of dyslipidaemia include bile acid-binding resins, HMG-CoA reductase inhibitors (statins), nicotinic acid, and fibric acid derivatives^[9]. Statin therapy, which inhibits cholesterol production in the liver, remains the recommended first-line therapy for LDL cholesterol reduction^[7].

Lipid-lowering drugs, while now prescribed to millions of adults, are not considered a good treatment option for everyone and can potentially cause side effects. When a patient with dyslipidaemia has a higher risk for developing cardiovascular disease, their doctor might feel that the benefits outweigh the risks. Medications might be needed after other treatment approaches have failed to help, especially to prevent coronary heart disease^[25].

Lifestyle changes

Making lifestyle changes to prevent further complications should be a priority^[25]. Natural treatments for dyslipidaemia can include taking steps to lower inflammation levels, improving your diet, getting regular exercise, and managing sources of physical and emotional stress^[25].

Dietary changes are fundamental to managing dyslipidaemia. A few changes in your diet can reduce cholesterol and improve your heart health^[17]. You should reduce saturated fats, which are found primarily in red meat and full-fat dairy products, as they raise your total cholesterol. Decreasing your consumption of saturated fats can reduce your LDL cholesterol^[17].

It’s important to eliminate trans fats, sometimes listed on food labels as “partially hydrogenated vegetable oil,” which are often used in margarines and store-bought cookies, crackers, and cakes. Trans fats raise overall cholesterol levels^[17].

You should eat foods rich in omega-3 fatty acids, which have heart-healthy benefits including reducing blood pressure. Foods with omega-3 fatty acids include salmon, mackerel, herring, walnuts, and flaxseeds^[17]. Increasing soluble fiber can also help, as it can reduce the absorption of cholesterol into your bloodstream. Soluble fiber is found in foods such as oatmeal, kidney beans, Brussels sprouts, apples, and pears^[17].

A heart-healthy eating pattern is high in wholegrains, fiber, vitamins, minerals, and healthy fats. This means choosing a variety of fresh and unprocessed foods, and limiting unhealthy fats, salt, and added sugar^[22].

Physical activity is another important component of managing dyslipidaemia. Adding exercise can help improve your cholesterol and boost the cholesterol-lowering power of medications^[17]. Regular exercise is part of a comprehensive approach to improving lipid levels.

If you eat more calories than you burn, you can get a buildup of triglycerides^[2]. Weight management through diet and exercise can help address this issue. Obesity, defined as a body mass index greater than 30 kg/m², is a risk factor for dyslipidaemia^[6].

If you smoke, quitting is important. Current cigarette smoking is a risk factor for dyslipidaemia and cardiovascular disease^[6]. Managing other health conditions such as diabetes and high blood pressure also plays a role in reducing your overall cardiovascular risk.