Hyperlipidemia Introduction Hyperlipidemia is one of the common diseases among middle-aged and elderly people, and it is also a disease that is of great concern and seriously affects the normal life of middle-aged and elderly people. To understand the definition of hyperlipidemia, it is important to know what is lipid first. Lipids are the lipids contained in plasma or serum, including cholesterol (CH), triacylglycerides (TG), phospholipids (PL) and free fatty acids (FFA). Cholesterol is further divided into cholesteryl esters and free cholesterol, and the sum of the two is total cholesterol (TC). Lipids are combined with apolipoproteins to form lipoproteins that are soluble in plasma for transport and metabolism. Lipoproteins can be classified into celiac, very low density lipoprotein, low density lipoprotein, medium density lipoprotein and high density lipoprotein by electrophoresis and ultracentrifugation according to their composition, density and properties. Disorders of lipid metabolism; abnormal lipid metabolism or transport; high plasma concentrations of one or more lipids, including high plasma TC and TG levels or low plasma HDL levels; and higher than normal plasma levels of TC, TG and various lipoproteins for the same age are called hyperlipidemia. Both hyper TC and hyper TG are hyperlipidemia, which can be manifested as simple hyper TC or simple hyper TG, or as mixed hyperlipidemia with high TC and high TG. Hyperlipidemia can be divided into two categories: primary and secondary. Primary is related to congenital and genetic origin and is due to single or multiple genetic defects that cause abnormalities in receptors, enzymes or apolipoproteins involved in lipoprotein transport and metabolism, or due to environmental factors (diet, nutrition, drugs) and through unknown mechanisms. Secondary to metabolic disorders (diabetes, hypertension, mucinous edema, hypothyroidism, obesity, liver and kidney disease, hyperadrenocorticism) or associated with other factors (age, gender, season, alcohol consumption, smoking, diet, physical activity, mental stress, emotional activity). Hyperlipidemia belongs to the categories of “phlegm”, “deficiency”, “chest paralysis” and “vertigo” in Chinese medicine. Classification of hyperlipidemia Blood lipids mainly refer to cholesterol and triglycerides in the blood serum. Whether the cholesterol level is increased, the triglyceride level is increased, or both, it is collectively called hyperlipidemia. Based on the results of serum total cholesterol, triglyceride and HDL-cholesterol measurements, hyperlipidemia is classified into the following four types: (1) Hypercholesterolemia: elevated serum total cholesterol level exceeding 5.72 mmol/L and normal triglyceride level, i.e. triglycerides <1.70 mmol/L. (2) Hypertriglyceridemia: increased serum triglyceride levels above 1.70 mmol/L with normal total cholesterol levels, i.e. total cholesterol.