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Hypercholesterolemia is the medical term for too much cholesterol in the blood. According to Genetics Home Reference, more than 30 million adults in the United States have high cholesterol. Experts from the American College of Cardiology report that heart disease was responsible for more than 800,000 deaths in the United States in 2016. Obesity is a serious problem in the United States, with 37.7% of Americans meeting the criteria for obesity and 7.7% meeting the criteria for extreme obesity.
This guide explains why the lipid panel is ordered and how the results are used in the diagnosis and management of chronic medical conditions. It also provides more information on high cholesterol, heart disease, and obesity.
The purpose of the lipid panel is to measure the amount of total cholesterol, high-density lipoprotein, low-density lipoprotein, and triglycerides in an individual’s blood. High-density lipoprotein, known as “good cholesterol,” takes cholesterol to the liver so it can be eliminated from the body. Low-density lipoprotein, known as “bad cholesterol,” can build up in the arteries, increasing the risk of heart disease and heart attack. Triglycerides are fats that are stored in the body until they can be used for energy.
The American Heart Association recommends cholesterol testing every four to six years once an individual has reached the age of 20. An individual with an elevated risk of heart disease, due to lifestyle factors or the presence of certain medical conditions, may need to have the cholesterol test more often. High blood pressure and diabetes are examples of conditions that can contribute to a heightened risk of heart disease.
The lipid panel requires a blood sample.
Some healthcare providers recommend that their patients refrain from eating or drinking anything other than water for nine to 12 hours before having blood drawn for a lipid panel. In 2016, the European Heart Journal issued a guideline stating that it’s not necessary to have an individual fast before having blood drawn for this test. However, not all health professionals have adopted this recommendation, so it’s important to check with the ordering physician to find out whether fasting is required.
High cholesterol can be caused by lifestyle factors and heredity. Certain medical conditions can also cause an individual to have elevated cholesterol levels. For example, people with diabetes tend to have lower levels of “good cholesterol” and higher levels of triglycerides and “bad” cholesterol, according to the American Heart Association. Kidney failure, hypothyroidism, and Cushing’s syndrome can also cause hypercholesterolemia. Cushing’s syndrome is an endocrine disorder characterized by the production of excess cortisol, a hormone that helps regulate blood sugar and plays a role in responding to stress.
Lifestyle factors are the habits that people have in their everyday lives. Smoking, lack of exercise, consuming fatty foods or foods containing high levels of cholesterol, exposure to secondhand smoke, and excess weight are all lifestyle factors that can lead to elevated cholesterol levels. High cholesterol can also be caused by certain genetic changes that are passed down from older generations of an individual’s family. According to Genetics Home Reference, mutations in the LDLRAP 1, LDLR, PCSK9, and APOB genes have all been linked to high cholesterol levels.
High cholesterol doesn’t always cause symptoms. In fact, many people don’t know they have elevated cholesterol levels until they have a heart attack or stroke. This is why it’s so important to get regular cholesterol checks.
Heart disease is a general term used to refer to conditions that can impair the function of the heart. When people use this term, they’re often referring to ischemic heart disease, which is a form of heart disease caused by narrowing of the coronary arteries. In people with ischemic heart disease, cholesterol combines with calcium and other substances to form plaque. This plaque accumulates on the inside of the arteries, making it difficult for blood to flow normally.
Several risk factors increase the likelihood that an individual will develop heart disease. Some of these factors, such as dietary habits, can be modified to reduce an individual’s risk. For example, consuming high amounts of saturated fat, not getting enough exercise, and using tobacco are all lifestyle factors that can contribute to heart disease. Factors that can’t be changed include a person’s age, genetic mutations, family history of heart disease, race, sex, and ethnicity. Although heart disease affects all racial and ethnic groups, American Indians, Pacific Islanders, and Asian Americans have a higher risk than other groups.
Like high cholesterol, heart disease may not cause any symptoms until it progresses enough to cause a stroke or heart attack. Some people with ischemic heart disease experience fatigue, chest pain, neck pain, and heightened levels of anxiety.
People gain weight when they consume more calories than they burn, however, the development of obesity isn’t so simple. For example, genetics plays an important role in determining someone’s weight. Some people naturally burn fewer calories than others, making it more difficult to shed excess pounds. Genetics also has an effect on hunger signals. Some people have trouble satisfying their hunger, causing them to overeat and take in excess calories.
Eating and exercise habits also play a role in the development of obesity. In modern society, fewer people have jobs requiring physical labor. Millions of people work with computers and other office equipment, causing them to spend most of their time sitting at a desk. Many people also drive to work or take public transportation rather than walking or riding a bicycle. As a result, it’s more difficult to burn calories.
Obesity doesn’t cause any specific symptoms. It’s characterized by a body mass index (BMI) of 30 or higher. An individual with a BMI of 40 or higher meets the criteria for extreme obesity.
Lab personnel carry out several procedures to determine how much cholesterol is present in a blood sample. To determine total cholesterol, an analyst performs a series of chemical reactions. One of these reactions produces a specific color, and cholesterol content is determined based on the intensity of that color. Lab personnel perform another set of reactions that produce glycerol, a byproduct of triglycerides. The glycerol is broken down into another substance, allowing the analyst to measure triglyceride content based on the intensity of the color produced.
To measure HDL cholesterol, lab personnel use a method that excludes other forms of cholesterol from the testing process. This allows an analyst to determine the amount of HDL present. Few labs measure LDL directly. Instead, they use a formula that estimates the amount of LDL in a person’s blood based on total cholesterol, HDL, and triglyceride measurements. The formula is Total Cholesterol – HDL Cholesterol – (Triglyceride Level/5) = LDL. Using this formula, someone with a TC of 150, an HDL level of 40, and a triglyceride level of 75 would have an estimated LDL of 95 (150 – 40 – 15 = 95).
Medications and lifestyle changes are typically used to treat high cholesterol. Most people with this condition take a statin, a type of drug that both lowers cholesterol and reduces the risk of stroke and heart attack. In some people, LDL levels are high even though the total cholesterol level is within normal limits. People with high LDL levels may benefit from taking statins even if their HDL and total cholesterol are normal. Statins may also be beneficial for older people with diabetes. Statins reduce cholesterol by preventing the liver from producing too much of it.
Resins, selective cholesterol absorption inhibitors, and PCSK9 inhibitors are also used to treat high cholesterol. Resin increases the amount of cholesterol excreted from the digestive system, reducing the amount of cholesterol left to circulate in the blood. Selective cholesterol absorption inhibitors reduce the amount of cholesterol absorbed in the intestines. PCSK9 inhibitors attach themselves to a liver protein involved in cholesterol production. This helps reduce LDL cholesterol levels.
Recommended lifestyle changes include quitting smoking, following a heart-healthy diet, increasing the amount of physical activity performed each day, and losing any excess weight. It’s important to stop smoking because smoking reduces the amount of HDL in the bloodstream, which can cause total cholesterol levels to increase. A good diet for managing cholesterol emphasizes poultry, fish, fruit, nuts, and vegetables. Consuming enough fiber is also important. People with high cholesterol are advised to limit their consumption of red meats, full-fat dairy products, desserts, and beverages sweetened with sugar.
The same lifestyle changes recommended for people with high cholesterol are advised for people with heart disease: following a heart-healthy diet, getting plenty of exercise, quitting smoking, and losing any excess weight. Medications and medical procedures may also be used to treat ischemic heart disease. Some medications are used to lower cholesterol, while others are used to reduce blood pressure and prevent the heart from having to work too hard to pump blood. People with angina (chest pain) caused by heart disease may take nitroglycerin or other nitrates to control their symptoms.
Percutaneous coronary intervention (PCI), transmyocardial laser revascularization, and coronary artery bypass grafting are some of the medical procedures used to treat heart disease. PCI involves threading a tube into a blocked artery and then inflating a balloon to relieve the blockage. After the blockage is removed, many people have stents implanted to keep their arteries open and prevent them from getting blocked again. Transmyocardial laser revascularization is used to relieve severe angina in people who are not good candidates for other procedures, or in people who haven’t gotten good results from other procedures. Coronary artery bypass grafting is a major surgery that involves using unblocked blood vessels to allow blood to flow around a blocked coronary artery.
Obese people are usually advised to make healthy lifestyle changes before turning to other treatment methods. These lifestyle changes focus on exercise, healthy eating habits, and good sleep habits. It’s important to consult with a doctor before starting any exercise program, as exercise may not be safe for some individuals. Following a heart-healthy diet that replaces soda, baked goods, snack foods, red meats, and full-fat dairy products with lean poultry, fish high in omega-3 fatty acids, fruits, and vegetables can help people with obesity lose weight. Several studies have identified a link between obesity and poor sleep habits. Thus, getting enough sleep each night can also help with weight loss.
Some people with obesity find behavioral weight loss plans helpful. These plans combine dietary changes and exercise goals with behavioral strategies to address underlying psychological issues that might be contributing to weight gain or difficulty losing weight. These programs typically offer access to dietitians and other medical professionals who can provide assistance with planning menus and forming good habits. Surgical procedures, such as gastric banding or gastric bypass, may be used to treat obesity when lifestyle changes and behavioral weight loss plans don’t work. These procedures can help prevent complications from obesity.
A cholesterol level of less than 200 mg/dL is considered desirable, while a total cholesterol of 200 to 239 mg/dL is considered borderline high. An individual has high cholesterol if his or her total cholesterol is 240 mg/dL or higher.
A triglyceride level of less than 150 mg/dL is considered normal. Higher levels of triglycerides are classified as borderline high (150 to 199 mg/dL), high (200 to 499 mg/dL), and very high (500 mg/dL or higher).
When it comes to HDL, a higher level is better than a lower level. An HDL level of 40 mg/dL is considered good, but an HDL level of 60 mg/dL is considered to have a protective effect against heart disease. An HDL reading of less than 40 mg/dL indicates that an individual has an increased risk of heart disease.
The lower an individual’s LDL level, the better. An LDL level of less than 100 mg/dL is considered optimal. LDL levels may also be categorized as near-optimal or above-optimal (100 to 129 mg/dL), borderline high (130 to 159 mg/dL), high (160 to 189 mg/dL), or very high (190 mg/dL or higher).
An individual with high cholesterol may need to have additional tests to determine his or her risk of developing heart disease or having a heart attack. These tests include an EKG, an echocardiogram, and a stress test. An EKG records the electrical activity of the heart, which helps medical professionals determine if there are any abnormalities. The echocardiogram is a type of ultrasound that helps determine if the heart has any structural or functional problems. A stress test helps determine if the heart is getting enough oxygen.
For more information on high cholesterol, heart disease, and obesity, plus how they’re diagnosed and treated, visit the following online resources.
|MedlinePlus||www.medlineplus.gov||Learn more about the lipid panel and other blood tests used to diagnose and manage high cholesterol and heart disease.|
|American Heart Association||www.heart.org||The AHA provides a wide variety of resources on heart-healthy diets, managing heart disease, and the basics of common heart conditions.|
|National Heart, Blood, and Lung Institute||www.nhlbi.nih.gov||Learn more about ischemic heart disease at the NHLBI website.|
|Centers for Disease Control and Prevention||www.cdc.gov||Access statistics on obesity and heart disease.|
|Genetics Home Reference||www.ghr.nlm.nih.gov||GHR provides comprehensive information on the genetic changes that may play a role in the development of high cholesterol, heart disease, and obesity.|