Analysis of Dyslipidemia: Contributing Factors and Classification from a Western Medical Perspective

Factors contributing to hyperlipidemia in Western medicine: Western medicine classifies hyperlipidemia into two main categories: primary hyperlipidemia and secondary hyperlipidemia.

●Etiology of Primary Hyperlipidemia

(1) Genetic factors. Heredity can cause hyperlipidemia through various mechanisms. Some occur at the molecular level of lipoproteins or apolipoproteins, often due to gene defects; others may occur at the cellular level, mainly manifested as defects in cell surface lipoprotein receptors and certain intracellular enzymes.

Currently, familial hypercholesterolemia is the most common clinically encountered condition in China. In Shanghai alone, dozens of patients from more than ten families have been identified. Zhongshan Hospital performed an autopsy on a case of death from familial hypercholesterolemia, finding extensive atherosclerotic plaques on the aortic intima, resembling a thick layer of cream cake, and multiple traces of myocardial infarction in the patient's heart.

(2) Dietary factors. The effects of dietary factors are complex, and a significant proportion of patients with hyperlipidemia have a close relationship with dietary factors. Excessive carbohydrate intake can affect insulin secretion, accelerate the synthesis of very low-density lipoprotein in the liver, and easily lead to hypertriglyceridemia. Excessive intake of cholesterol and animal fat is also related to the formation of hypercholesterolemia. Other dietary components, such as long-term excessive intake of fat, protein, and carbohydrates, and insufficient dietary fiber intake, are also related to the occurrence of this disease.

●Etiology of Secondary Hyperlipidemia Secondary hyperlipidemia is caused by other primary diseases, including obesity, glycogen storage disease, diabetes, liver disease, kidney disease, gout, Addison's disease, thyroid disease, Cushing's syndrome, and abnormal globulinemia. Secondary hyperlipoproteinemia is quite common clinically. Without detailed examination, the primary disease is often overlooked, leading to symptomatic treatment without addressing the root cause, which is detrimental to treatment.

Classification of Hyperlipidemia: Hyperlipidemia can be classified into several types based on the different abnormal lipid components: Normal total cholesterol should be below 5.2 mmol/L. A level exceeding 5.72 mmol/L can be diagnosed as hypercholesterolemia. Total cholesterol levels between these two values ​​are considered borderline or borderline elevated, and are also abnormal. The exact cause of elevated total cholesterol is still unknown. Some cases are related to family history, with many family members having elevated cholesterol, and some developing coronary heart disease at a young age. Some patients may have elevated total cholesterol due to long-term consumption of high-cholesterol foods such as fatty meat, lard, animal organs, and shellfish. In addition, obesity, aging, and menopause in women are also associated with elevated total cholesterol. In summary, most cases are caused by genetic defects or the interaction of these defects with environmental factors. However, it is currently difficult to diagnose the cause in every patient, hence the term "primary hypercholesterolemia." In a small number of patients, the onset of hypercholesterolemia is caused by other diseases, such as hypothyroidism, chronic kidney disease, or diabetes. Long-term use of certain medications, such as the diuretic hydrochlorothiazide and the hormones prednisone or dexamethasone, can also lead to elevated blood cholesterol. Because the onset of this disease occurs on the basis of the pre-existing condition, it is called secondary hypercholesterolemia.

Regardless of whether the disease is primary or secondary, there is often an increase in low-density lipoprotein cholesterol (LDL-C). Elevated LDL-C is a significant risk factor for coronary heart disease; therefore, preventing and treating hypercholesterolemia is one of the key measures for preventing coronary heart disease and atherosclerosis.

This condition is defined as a blood triglyceride level exceeding 1.7 mmol/L. Its causes are related to long-term consumption of excessive sugary foods, alcohol consumption, smoking, and insufficient physical activity. Significantly elevated triglycerides are also common in familial genetic diseases, related to genetic abnormalities. In these patients, the upper layer of blood often appears creamy, while the lower layer is cloudy. Elevated triglycerides are also a significant risk factor for coronary heart disease and atherosclerosis.

This condition can be diagnosed when both total cholesterol and triglycerides are elevated in the blood. Its causes are related to genetics, diet, or other diseases. Because both lipid components are abnormal, and high-density lipoprotein cholesterol is often significantly reduced, the likelihood of developing coronary heart disease is higher.