High-Density Lipoproteins (HDLC)
Why this test?
- To assess the risk of developing atherosclerosis and heart problems.
- To monitor the effectiveness of a low-fat diet.
In what cases is it prescribed?
- Analysis of HDL is performed during routine preventive examinations or when total cholesterol is elevated as part of a lipidogram. A lipidogram is recommended for all adults over the age of 20 at least once every 5 years. It can be prescribed more often (several times a year) if the patient is offered a diet with a restriction of animal fats and / or he takes drugs that lower the level of cholesterol. In these cases, it is checked whether the patient reaches the target level of HDL-C and total cholesterol and, accordingly, the risk of cardiovascular diseases decreases.
- If there are risk factors for the development of cardiovascular diseases: smoking,age (men over 45 years old, women over 55 years old), increased blood pressure (140/90 mm Hg and higher), cases of high cholesterol or cardiovascular diseases in other family members (heart attack or stroke in a close relative male younger than 55 years old, female - younger than 65 years old),existing coronary heart disease, myocardial infarction or stroke,diabetes, excess body weight, alcohol abuse, intake of large amounts of food containing animal fats, low physical activity.
- If a child's family had cases of high cholesterol or heart disease at a young age, it is recommended to take a cholesterol test for the first time between the ages of 2 and 10.
Cholesterol (Cholesterol) is a fatty substance vital to the body. The correct scientific name for this substance is «cholesterol» (the ending -ol indicates that it belongs to alcohols), however, the name «cholesterol», which we will use later in this article, has become widespread in the mass literature. Cholesterol is formed in the liver, and also enters the body with food, mainly meat and dairy products. Cholesterol is involved in the formation of cell membranes of all organs and tissues of the body. Hormones are formed on the basis of cholesterol, which participate in the growth, development of the body and the implementation of the function of reproduction. Bile acids are formed from it, thanks to which fats are absorbed in the intestines.
Cholesterol does not dissolve in water, therefore, to move around the body, it is «packaged» in a protein shell consisting of special proteins - apolipoproteins. The resulting complex (cholesterol + apolipoprotein) is called a lipoprotein. Several types of lipoproteins circulate in the blood, differing in the proportions of the component composition:
- very low density lipoproteins (VLDL),
- low-density lipoprotein (LDL),
- high-density lipoprotein (HDL).
High-density lipoproteins consist mainly of the protein part and contain cholesterol. Their main function is to carry excess cholesterol back to the liver, from where they are excreted in the form of bile acids. Therefore, HDL cholesterol (HDL-C) is also called «good cholesterol». About 30% of the total cholesterol (cholesterol) in the blood is included in HDL.
If a person has a hereditary predisposition to high cholesterol or eats too much fatty food, the level of cholesterol in the blood can rise, so that its excess will not be completely removed by high-density lipoproteins. It begins to be deposited in the walls of blood vessels in the form of plaques, which can limit the movement of blood through the vessel, and also make the vessels more rigid (atherosclerosis), which significantly increases the risk of heart diseases (ischemic disease, heart attack) and stroke.
High values of HDL cholesterol reduce the risk of developing plaques in blood vessels, as they contribute to the removal of excess cholesterol from the body. A decrease in HDL cholesterol, even with a normal level of total cholesterol and its fractions, leads to the progression of atherosclerosis.