In the previous article, I discussed the risk factors for atherosclerosis. Most of us, after the age of 20, have found ourselves at direct risk. To reduce this danger, it is necessary to identify the risk factors that can be treated. These include: arterial hypertension, diabetes, obesity, tobacco smoking, reduced HDL cholesterol levels and elevated LDL cholesterol levels.
At this stage, we know that there is a constant relationship between the concentration of cholesterol in plasma and the risk of developing ischemic heart disease. Cholesterol in plasma is transported primarily by two classes of lipoproteins (proteins): low-density (LDL) and high-density (HDL). Most cholesterol is transported by LDL, and elevated levels of LDL are responsible for the development of atherosclerosis. HDL transports approximately 25–30 percent of cholesterol, and these proteins are attributed with an anti-atherosclerotic role (“good cholesterol”). In addition to the two cholesterol fractions, the concentration of triglycerides in plasma is less important. It is most often an equivalent of other abnormalities. However, an isolated elevation of triglyceride levels is not a direct cause of atherosclerosis.
Elevated cholesterol levels can be divided into primary and secondary forms. The main therapeutic problem is posed by the primary forms. Secondary forms occur in the course of diabetes, kidney failure, obstructive jaundice, hypothyroidism, alcoholism, multiple myeloma, and the use of certain medications (e.g. hormonal oral contraceptives, adrenal steroids and thiazides). Based on studies conducted by major centers, the threshold cholesterol level was established at 200 mg/dl.
Above these levels, the risk of ischemic heart disease increases as cholesterol levels rise (for example, with a cholesterol level of 250 mg/dl it is twice as high, and with a level of 300 mg/dl it is four times as high). For European populations and Poland, cholesterol levels between 200 and 249 mg/dl are considered elevated.
The basis of proper treatment is an accurate diagnosis. The basic test is the measurement of total cholesterol in blood serum. This does not require preparation of the person being tested, since the concentration of cholesterol in plasma does not depend on the meal consumed. The results obtained are interpreted as follows: 1. If the serum cholesterol level does not exceed 200 mg/dl, no risk of atherosclerosis is found. Dietary recommendations and a recommendation to have the next test within 5 years are sufficient.
2. If a cholesterol level between 200 and 249 mg/dl is found and there is additionally one risk factor, the person being tested receives dietary recommendations and is advised to have another test within one year.
3. If the cholesterol level is higher than 249 mg/dl, or is between 200 and 249 mg/dl with two risk factors, the person is referred for the second stage of testing.
The purpose of the second stage of testing is to determine: total cholesterol, total triglycerides, HDL cholesterol and LDL cholesterol. I would like to draw attention to HDL cholesterol (“good” cholesterol), whose levels should be higher than 35 mg/dl. The most common causes of reduced HDL cholesterol levels are cigarette smoking, obesity, low physical activity, elevated triglyceride levels and certain medications. Reducing elevated plasma levels decreases not only the risk of ischemic disease but, when coronary heart disease is already present, also delays its progression and may even reverse atherosclerosis of the coronary arteries. The Central Analytical Laboratory of the Hospital in Bolesławiec has been measuring cholesterol and its fractions, as well as triglyceride levels, for several years.