Dyslipidemia

Introduction Cardiovascular disease has become the first cause of death in urban and rural populations in China. The cardiovascular disease in China is characterized by high incidence of stroke and low incidence of coronary heart disease, but the incidence and mortality of coronary heart disease have gradually increased in the past 20 years. In large cities with rapid economic development, such as Beijing, the monitoring results showed that the incidence of hemorrhagic stroke decreased significantly from 1984 to 1999, while the incidence of ischemic stroke increased significantly, indicating atherosclerosis. The incidence of underlying ischemic cardiovascular disease, including coronary heart disease and ischemic stroke, is increasing. Elevated serum total cholesterol or low-density lipoprotein cholesterol is one of the independent risk factors for coronary heart disease and ischemic stroke. To this end, the prevention and treatment of dyslipidemia must be given early attention.

Cause

Causes of dyslipidemia

From the reasons, one is determined by genetic factors, and the other depends on the environmental factors of the day after tomorrow. The latter category accounts for the majority. Mainly caused by four factors:

1 lifestyle, including dietary nutrition, physical activity, mental stress, emotional changes, tobacco and alcohol hobbies.

2 drug effects, such as thiazide diuretics, beta blockers, adrenocortical hormones, oral contraceptives and the like.

3 endocrine and metabolic disorders, mainly diabetes, thyroid dysfunction, obesity, hyperuricemia and so on.

4 certain diseases, such as kidney disease, combined with lupus erythematosus, bone marrow disease, etc.

In addition, the determination of blood lipids (proteins) can be significantly affected by the condition of the laboratory and the subject taking blood. Blood should be taken after maintaining a normal diet for half a month and fasting for 12 hours. The day before, no alcohol or vigorous activities. Under normal circumstances, blood lipid (protein) levels may increase or decrease by 10%, and the laboratory allows 3%-5% variation.

Diabetes: especially in type 2 diabetes with obesity, blood cholesterol, low-density lipoprotein cholesterol, triglycerides are elevated, while high-density lipoprotein cholesterol and apolipoprotein a are decreased.

Nephrotic syndrome: In total nephrotic syndrome, blood total cholesterol and low-density lipoprotein cholesterol are significantly elevated, and triglycerides are also elevated.

Relationship with obesity: Fat metabolism in obese people is characterized by elevated plasma free fatty acids, and lipid levels such as cholesterol, triglycerides, and total lipids are generally increased. Explain the disorder of fat metabolism. The obese person's plasma cholesterol level may be 55.8% above 5.2 mmol/L. After the age of 60, women's plasma cholesterol levels will increase significantly after the age of 50.

In the case of obesity, the body's mobilization of free fatty acids is reduced, free fatty acids in the blood are accumulated, and blood lipid capacity is increased. Patients with high triglycerideemia caused by carbohydrates are prone to obesity. When these patients eat more or normal carbohydrates, plasma triglycerides increase; while reducing carbohydrate intake, hyperlipidemia can be improved or even disappeared. Similarly, weight loss can also reduce plasma triglycerides in these patients to normal levels. The rise in plasma cholesterol and triglycerides is directly proportional to the degree of obesity. Decreased blood lipid levels are important for preventing atherosclerosis and coronary heart disease. Therefore, it is necessary for obese people to control their diet and lose weight.

an examination

Related inspection

Determination of Serum Total Lipoxane B2 Serum Apolipoprotein by Lipoprotein Electrophoresis Serum Apolipoprotein CII

There are many clinical tests for detecting blood lipids. The basic tests for blood lipids are TC, TG, high density Lipoprotein-cholesterol (HDL-C) and LDL-C. Other blood lipids such as apoA I, apoB, and Lp(a) are among the research items and are not included in the clinical basic testing program.

1. TC: TC refers to the sum of cholesterol contained in each lipoprotein in the blood. The main factors affecting TC levels are: (1) Age and gender: TC levels often increase with age, but do not rise or even decline after 70 years of age, younger women are younger than men, and postmenopausal TC levels are lower. Male of the same age. (2) Eating habits: Long-term high cholesterol and high saturated fatty acid intake can cause TC to rise. (3) Genetic factors: mutations in enzymes related to lipoprotein metabolism or receptor genes are the main causes of significant increase in TC.

2. TG: The clinically determined TG is the sum of TG contained in each lipoprotein in plasma. TG levels are also affected by both genetic and environmental factors. Unlike TC, the TG level of the same individual is greatly affected by factors such as diet and different time, so the TG value may be significantly different in the same individual when it is measured multiple times. Serum TG levels in the population showed a significant positive skew distribution.

3. HDL-C: Basic research confirmed that HDL can transport cholesterol from peripheral tissues such as blood vessel walls to the liver for catabolism, suggesting that HDL has anti-atherosclerotic effects. Since there are many components in HDL, there is no way to comprehensively detect the amount and function of HDL in the clinic. Therefore, by detecting the amount of cholesterol contained in the blood, the amount of HDL in plasma is indirectly understood.

4. LDL-C: LDL metabolism is relatively simple, and cholesterol accounts for about 50% of the weight of LDL, so it is currently believed that the concentration of LDL-C can basically reflect the total amount of blood LDL. Increased LDL-C is a major lipid risk factor for the development and progression of atherosclerosis. In general, LDL-C is parallel to TC, but TC level is also affected by HDL-C level. Therefore, it is best to use LDL-C instead of TC as a risk assessment for coronary heart disease and other atherosclerotic diseases.

5. Apo AI: The serum apo AI level in the normal population is mostly in the range of 1.2-1.6 g/L, and the female is slightly higher than the male.

6. ApoB: Serum Apo B in the normal population is in the range of 0.8 to 1. lg / L.

7. Lp (a): Serum Lp (a) concentration is mainly related to heredity, and is basically independent of gender, age, weight, moderate physical exercise and most cholesterol-lowering drugs. The Lp(a) level in the normal population is obviously skewed. Although some individuals can be as high as 10OOmg/L or above, 80% of normal people are below 2OOmg/L, and the average number in the literature is 120-180mg/L. The number of digits is lower than this value. Usually 300mg / L is an important boundary, above which the risk of coronary heart disease is significantly increased. Clinical methods for Lp(a) detection have not been standardized.

8. sLDL: The particle size of LDL in plasma is not uniform, and each individual has large, medium and small particle LDL. Plasma TG levels have been shown to correlate with LDL particle structure. When TGL (l5Omg/dl), large and light LDL is more, LDL spectrum is A when plasma electrophoresis; when TG>1.7Ommol/L, sLDL level is increased, LDL spectrum is B type. With elevated plasma apo B levels, HDL-C and apo AI levels were reduced. It is currently believed that sLDL has a strong atherogenic effect. However, there is no simple and reliable practical method for detecting sLDL in clinic.

The legal unit of measurement for each blood lipid project is mmol/L, and some countries in the world use mg/dl. The conversion factor of TC, HDL-C, and LDL-C is mg/dl×O.0259=mmol/L: the conversion factor of TG is mg/dl×O.0113=mmol/L.

Differential diagnosis

Symptoms of dyslipidemia

Dyslipidemia is different from hyperlipidemia. There are usually 4 lipid tests, namely total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and triglycerides (TG). ). Hyperlipidemia generally refers to three elevations other than HDL-C and is a risk factor for cardiovascular disease. However, an increase in HDL-C is conducive to the prevention and treatment of cardiovascular disease, and the decline of HDL-C is a risk factor for cardiovascular disease. Therefore, "dyslipidemia" is more general than the term "hyperlipidemia" to summarize people's concerns about blood lipid changes.

The material in this site is intended to be of general informational use and is not intended to constitute medical advice, probable diagnosis, or recommended treatments.