Hyperlipidemia: In-depth analysis of its causes, diagnostic criteria, and cascading damage to the body.

Causes of Hyperlipidemia

The main lipids in the human body include cholesterol and triglycerides. There are two main sources of blood lipids: exogenous lipids, which are formed from lipids absorbed after digestion from our daily diet; and endogenous lipids, which are synthesized and released into the bloodstream by the liver, fat cells, and other tissues during normal metabolism. In older adults, liver metabolism slows down, and the activity of lipases that break down fat decreases, making it easier for fat to accumulate. Combined with the effects of free radicals, this causes blood lipids to deposit on the arterial walls, leading to arteriosclerosis. This is a manifestation of vascular aging in the elderly and a pathological basis of aging.

Inclusion and Exclusion Criteria for Hyperlipidemia

Inclusion Criteria: The diagnosis of hyperlipidemia is based on the criteria established by the Lipid Dyslipidemia Prevention and Control Strategy Special Group of the Editorial Board of the Chinese Journal of Cardiovascular Diseases: Serum triglyceride (TG) level > 1.70 mmol/L, or serum total cholesterol (TC) level > 5.72 mmol/L, or low-density lipoprotein cholesterol (LDL-C) level > 3.64 mmol/L, or high-density lipoprotein cholesterol (HDL-C) < 0.91 mmol/L.
Exclusion Criteria:

1) Concomitant tumors;

2) Thyroid dysfunction;

3) History of stroke;

4) Concomitant coronary heart disease;

5) Pregnant and lactating women.

Harmful Effects of Hyperlipidemia

With the improvement of people's living standards, the lifestyles and dietary structures of urban residents are gradually changing, and the prevalence of hyperlipidemia is gradually increasing. Hyperlipidemia is often closely related to various diseases such as cardiovascular and cerebrovascular diseases, hepatobiliary diseases, and diabetes. Cardiovascular and cerebrovascular diseases mainly originate from atherosclerosis, and more than 80% of atherosclerosis is caused by hyperlipidemia. The prevalence of hyperlipidemia is 3 to 4 times higher than that of patients diagnosed with cardiovascular and cerebrovascular diseases. Numerous studies have shown that hyperlipidemia is a risk factor for stroke, coronary heart disease, myocardial infarction, and sudden death. Furthermore, hyperlipidemia is also a significant risk factor for hypertension, impaired glucose tolerance, and diabetes. Therefore, the dangers of hyperlipidemia must be taken very seriously, and active prevention and treatment are essential.

1) Hyperlipidemia and Hypertension: After atherosclerosis develops in the body, it leads to myocardial dysfunction, and angiotensin-converting enzyme is activated in large quantities, causing arterial spasm and inducing the adrenal glands to secrete pressor hormones, resulting in elevated blood pressure. In healthy individuals, the lining of blood vessels is smooth and unobstructed. Elevated blood lipids gradually deposit under the lining, forming yellow, atherosclerotic plaques. Over time, these plaques rupture, bleed, narrow the lumen, and increase blood flow resistance, thus raising blood pressure. Elevated blood lipids, deposited in the arterial intima, can cause arteriosclerosis, weakening the elasticity of the blood vessel walls and further increasing blood pressure. When blood lipids are elevated, blood viscosity increases, increasing blood flow resistance and thus raising blood pressure. Hyperlipidemia can also reduce the sensitivity to antihypertensive drugs, making antihypertensive treatment more difficult; therefore, blood lipids should be lowered simultaneously with hypertension treatment.

2) Hyperlipidemia and Diabetes: Statistics show that approximately 40% of diabetic patients have lipid metabolism disorders. These are characterized by elevated triglycerides and decreased high-density lipoprotein (HDL). The reason for elevated blood lipids in diabetic patients is that when insulin is insufficient, the activity of lipases in the body decreases, making blood lipids more prone to increase. Furthermore, diabetes itself, in addition to glucose metabolism disorders, is also accompanied by disturbances in fat, protein, water, and electrolytes. Free fatty acids are frequently mobilized from fat stores, increasing the concentration of triglycerides and free fatty acids in the blood. Furthermore, type 2 diabetics often overeat and exercise, leading to increased lipid synthesis, which also contributes to elevated blood lipids. Obese individuals with high blood lipids have a relatively reduced number of insulin receptors, resulting in insulin resistance and increasing the risk of diabetes. Elevated blood lipids also increase the risk of cardiovascular and cerebrovascular complications.

3) Hyperlipidemia and Coronary Heart Disease: When long-term high blood lipids lead to atherosclerosis, the blood flow in the coronary arteries decreases, the lumen narrows, and the blood supply to the myocardium decreases, causing myocardial ischemia, leading to angina pectoris and coronary heart disease.

4) Hyperlipidemia Can Cause Liver Damage: Long-term high blood lipids can lead to fatty liver. Atherosclerosis of the hepatic artery damages the liver lobules, causing structural changes and eventually cirrhosis, impairing liver function.