Obesity

Introduction to obesity Obesity is a common, ancient group of metabolic disorders. When the body eats more calories than calories, the excess calories are stored in the body in the form of fat, which exceeds the normal physiological requirements, and when it reaches a certain value, it becomes obesity. An increase in body fat such that body weight exceeds 20% of standard body weight or body mass index [BMI = body weight (k) / height (m) 2] greater than 24 is called obesity. If there is no obvious cause, it can be called simple obesity. The cause of the disease is called secondary obesity. If there is no obvious cause, it can be called simple obesity; those with a clear cause are called secondary obesity. basic knowledge The proportion of illness: 10% Susceptible people: no special people Mode of infection: non-infectious Complications: hyperuricemia polycystic ovary syndrome

Cause of obesity

Genetic factors (30%):

Epidemiological surveys show that some people with simple obesity have family morbidity, and both parents are obese. The children who are born with simple obesity are 5-8 times higher than those born to both parents. Vanllallie vs. 1333 A longitudinal survey of children born between 1965 and 1970 also found that one parent has obesity, and their children grow older, and their odd ratio increases, 1 to 2 Obese children from early age to adulthood were 1.3 in the early stage, 4.7 in the 3 to 5 years old, 8.8 in the 6 to 9 years old, 22.3 in the 10 to 14 years old, and 17.5 in the 15 to 17 years old.

Neuropsychiatric factors (30%):

It is known that there are two pairs of nerve nuclei related to feeding behavior in the hypothalamus of humans and various animals. One pair is the contralateral contralateral nucleus (VMH), also known as the satiety center; the other pair is the ventrolateral nucleus (LHA). Also known as the hunger center, when the center is full of excitement, there is a feeling of fullness and refusal to eat. When it is destroyed, the appetite is greatly increased. When the hunger center is excited, the appetite is strong, and when it is destroyed, it is anorexia and antifeeding. The two regulate each other, restrict each other, and are in dynamic balance under physiological conditions. State, the appetite is regulated in the normal range and maintains normal body weight. When the hypothalamus develops lesions, whether it is inflammation sequelae (such as meningitis, encephalitis), trauma, tumor and other pathological changes, such as ventromedial nucleus destruction, then The ventrolateral nucleus function is relatively phlegm and then gluttony, causing obesity. Conversely, when the ventrolateral nucleus is destroyed, the ventromedial nucleus functions relatively sputum and then anorexia, causing weight loss. In addition, the area has close anatomical connections with higher nervous tissues. The latter can also regulate the feeding center to a certain extent, and the blood-brain barrier at the hypothalamus is relatively weak. This anatomical feature makes the various biological active factors in the blood easy to The migration affects the feeding behavior. These factors include: glucose, free fatty acids, norepinephrine, dopamine, serotonin, insulin, etc. In addition, mental factors often affect appetite, and the function of the prey center is controlled by the mental state. When the spirit is over-stressed and the sympathetic nerves are stimulated or the adrenergic nerves are stimulated (especially the alpha receptors predominate), the appetite is inhibited; when the vagus nerve is excited and the insulin secretion is increased, the appetite is often hyperthyroidized, and the ventromedial nucleus is the sympathetic center. The ventrolateral nucleus is the parasympathetic center, which plays an important role in the pathogenesis of this disease.

Hyperinsulinemia (30%):

In recent years, the role of hyperinsulinemia in the pathogenesis of obesity has attracted attention. Obesity often coexists with hyperinsulinemia, but it is generally believed that hyperinsulinemia causes obesity, and insulin release in hyperinsulinemia obesity is about normal. 3 times the person. Insulin has a significant role in promoting fat accumulation. It is believed that insulin can be used as an indicator of total lipid content and can be used as a monitoring factor for obesity in a certain sense. Some people think that plasma insulin concentration is significantly positively correlated with total lipid content. .

Abnormal brown adipose tissue (5%):

Brown adipose tissue is an adipose tissue that has been discovered in recent years. It corresponds to white adipose tissue mainly distributed under the skin and around the internal organs. The distribution of brown adipose tissue is limited, only distributed between the shoulder blades, the neck and back, and the armpit. The mediastinum and the periphery of the kidney have a light brown appearance and a relatively small change in cell volume. White adipose tissue is a form of energy storage. The body stores excess energy in the form of neutral fat. When the body needs energy, the neutral fat is hydrolyzed in the fat cells. The volume of white fat cells changes with the release energy and storage energy. Big. The brown adipose tissue is functionally a thermogenic organ, that is, when the body ingests or is stimulated by the cold, the fat in the brown fat cells burns, thereby determining the energy metabolism level of the body. The above two conditions are called feeding-induced heat production. And cold induces heat production. Of course, the function of this special protein is affected by many factors. It can be seen that the brown adipose tissue is directly involved in the total regulation of heat in the body, and the excess heat in the body is released to the outside of the body, so that the body's energy metabolism tends to balance. .

Obesity prevention

Obesity should be based on prevention. People should be aware of their dangers and keep their weight as normal as possible. Prevention of obesity should start from childhood. At present, obesity is understood as the normal physiological process in the pathological environment. The main reason for the increase in the prevalence of obesity is the environment, not the "pathological" effect of metabolic defects or the mutation of individual genes. Since the factors of the remains are immutable, it is necessary to regulate the lifestyle, that is, a reasonable diet and appropriate physical strength. Activities to control the rise in weight, based on this new concept, governments are committed to promoting healthy lifestyles and general prevention programs.

In general, there are three preventive measures, namely universal prevention, selective prevention and targeted prevention.

Universal prevention : Targeting the population as a whole, stabilizing obesity levels and ultimately reducing the incidence of obesity and reducing the prevalence of obesity, changing lifestyles by improving dietary structure and promoting appropriate physical activity and reducing smoking and drinking, ultimately Reduce obesity-related diseases and achieve universal prevention.

Selective prevention : It aims to educate people at high risk of obesity so that they can fight against risk factors. These risk factors may come from heredity, making them vulnerable to obesity. The measures taken are for easy exposure to high risk. Local populations, such as schools, community centers, and primary prevention sites, start with education and implement specific interventions. The Ministry of Educations adoption of such preventive measures in children has reduced the prevalence of obesity from 15%. To 12.5%.

Obesity complications Complications hyperuricemia polycystic ovary syndrome

1. Obesity with abnormal glucose metabolism and insulin resistance Obesity can lead to abnormal glucose metabolism and insulin resistance. Obesity is closely related to the incidence of type 2 diabetes. 70% to 80% of people over 40 years old are suffering from diabetes. There is obesity before the disease.

2, obesity with hyperlipidemia Obesity often associated with hyperlipidemia, hypertension, impaired glucose tolerance, etc., and become the main cause of arteriosclerosis, more recently, more and more studies believe that fat distribution of obese people, especially visceral Obesity is clearly associated with the above comorbidities.

3, obesity with hypertension, obesity, high prevalence of hypertension, obesity is a risk factor for hypertension, hypertension can cause obesity, most epidemiological survey results show that obesity has a high incidence of hypertension, obese people with circulating plasma Increased cardiac output, increased heart rate, increased persistent sympathetic nerve excitability and sodium reabsorption, resulting in high blood pressure, resulting in increased peripheral vascular resistance and hypertensive cardiac hypertrophy.

4. Obesity with cardiac hypertrophy and ischemic heart disease Obesity often coexists with diseases such as hypertension, hyperlipidemia and impaired glucose tolerance, and these diseases are closely related to the occurrence of arteriosclerotic diseases. Among obese people The left ventricular end-diastolic pressure abnormally increases, sometimes leading to cardiac hypertrophy, and myocardial ischemia caused by cardiac hypertrophy often exacerbates diastolic dysfunction.

5. Obesity with obstructive sleep apnea syndrome Obesity is three times more likely to develop obstructive sleep apnea syndrome (OSAS) than non-obese people, and about 50% of adult obese men may have OSAS.

Obesity Symptoms Common Symptoms Male Obesity Visceral Obesity Subcutaneous Fat Increase Skin Tension Increase Adolescent Obesity Secondary Obesity Lipodystrophy Sleepiness Glucose Metabolic Disorder Female Obesity

1, the general performance of simple obesity can be seen at any age, juvenile type from childhood obesity; adult type more onset of 20 to 25 years old; but clinically 40 to 50 years old middle-aged women, more than 60 to 70 years old Older people are not uncommon. About 1/2 adult obese people have a history of childhood obesity, generally with a slow increase in body weight (except after women give birth). The body weight increases rapidly in a short period of time. Secondary obesity should be considered. The neck is the main part of the trunk, the trunk and the head, while the female is mainly the abdomen, lower abdomen, chest breasts and buttocks.

The characteristics of obese people are that they are short and fat, round and round, narrow and wide on the face, double squat, neck short and thick, and the skin folds of the backrest headrest are obviously thickened, chest circumference and intercostal space are not obvious. The milk is thickened by the thickening of the subcutaneous fat. When standing, the abdomen protrudes forward and is higher than the plane of the chest. The umbilicus is deep concave. In a short period of time, the obese person is on both sides of the lower abdomen, and the upper thigh and the upper part of the upper arm and the outer side of the buttock are visible with purple lines or White lines, the child's obese external genitalia is buried in the subcutaneous fat of the perineum and the penis appears small and short, the fingers, toes are short and short, the back of the hand is thickened by the fat and the skin of the metacarpophalangeal joint is sunken, and the bony is not obvious.

Mild to moderate primary obesity may have no symptoms. People with severe obesity are more afraid of heat, have decreased mobility, and even have mild shortness of breath during activities. They may have snoring during sleep, and may have hypertension, diabetes, gout, etc. Clinical manifestations.

2, other performance

(1) Obesity and cardiovascular system : obesity patients with coronary heart disease, the risk of hypertension is significantly higher than non-obese, the incidence is generally 5 to 10 times higher than non-obese, especially the central obesity with high waist-to-hip ratio Patients, obesity can cause cardiac hypertrophy, thickening of the posterior wall and interventricular septum, cardiac hypertrophy with blood volume, intracellular and intercellular fluid increase, ventricular end-diastolic pressure, pulmonary artery pressure and pulmonary capillary wedge pressure are increased, some obese people exist Impaired left ventricular function and obesity myocardial disease, the incidence of sudden death in obese patients is significantly increased, may be related to myocardial hypertrophy, arrhythmia caused by fat infiltration of cardiac conduction system and the occurrence of cardiac ischemia, hypertension in obese patients Very common, but also a major risk factor for heart and kidney disease, blood pressure will recover after weight loss.

(2) Respiratory function changes in obesity: obesity patients have reduced lung capacity and decreased lung compliance, which can lead to a variety of pulmonary dysfunction, such as obesity hypoventilation syndrome, clinical sleepiness, obesity, alveolar hypoventilation Characteristics, often accompanied by obstructive sleep apnea, severe cases can cause pulmonary heart syndrome (Pickwickian's syndrome), due to thickening of adipose tissue in the abdominal and chest wall, increased diaphragm muscles and decreased lung capacity, poor lung ventilation, causing post-activity breathing Difficulties, severe cases can lead to hypoxia, cyanosis, hypercapnia, and even pulmonary hypertension leading to heart failure, such heart failure often poor response to cardiotonic agents, diuretics, in addition, severe obesity, can still cause sleep apnea, even See the report of death.

(3) Sugar, fat metabolism of obesity : excessive consumption of calories promotes the synthesis and catabolism of triacylglycerol, lipid metabolism of obesity is more active, and relative glucose metabolism is inhibited. This metabolic change is involved in insulin resistance. Formation, obesity lipid metabolism is accompanied by metabolic disorders, hypertriglyceridemia, hypercholesterolemia and low-density lipoprotein cholesterol, etc., glucose metabolism disorder is abnormal or even impaired glucose tolerance In clinical diabetes, when the body weight exceeds 20% of the normal range, the incidence of diabetes is more than doubled. When BMI>35, the mortality rate is almost 8 times higher than that of normal weight. Central obesity significantly increases the risk of diabetes.

(4) Obesity and musculoskeletal disorders :

1 arthritis: the most common is osteoarthritis, due to long-term weight bearing, the articular cartilage surface structure changes, knee joint lesions are most common.

2 Gout: About 10% of obese patients have hyperuricemia and are prone to gout.

3 Osteoporosis: Because adipose tissue can synthesize and secrete estrogen, the main source of estrogen in postmenopausal women is secreted by adipose tissue. Many studies have found that obese women after menopause have higher bone density than normal weight. Osteoporosis is rare in obese patients.

(5) Endocrine system changes in obesity :

1 Growth hormone: The release of growth hormone in obese people is reduced, especially insensitive to factors that stimulate the release of growth hormone.

2 Pituitary-adrenal axis: The secretion of adrenal cortex hormone is increased in obese people, the secretion rhythm is normal, but the peak value is increased, and the ACTH concentration is also slightly increased.

3 hypothalamic-pituitary-gonadal axis: obesity is associated with hypogonadism, pituitary gonadotropin reduction, testosterone response to gonadotropin is reduced, male obese, blood total testosterone (T) level is reduced, but light In obesity, free testosterone (FT) is still normal, probably due to the decrease of sex hormone binding globulin (SHBG), while FT can also be decreased in severely obese people. In addition, adipose tissue can secrete estrogen, so obese people are often accompanied by Increased blood estrogen levels, obese girls, early menarche, adult women with obesity often have menstrual disorders, increased ovarian transparency, emergence of egg-free follicles, decreased blood SHBG levels, hairy, anovulatory menstruation or amenorrhea, adolescents Obesity, the incidence of infertility increased, often accompanied by polycystic ovary and surgery, obesity in the mid-menstrual period, the peak of FSH is low and the level of progesterone (P) in the luteal phase is low, ovarian function decline and FSH level Elevation occurs early, men are accompanied by decreased sexual desire and feminization, and the incidence of estrogen-related tumors is significantly increased.

4 Hypothalamic-pituitary-thyroid axis: Obesity thyroid responsiveness to TSH decreased, and pituitary responsiveness to TRH decreased.

(6) Obesity and insulin resistance : Body fat accumulation can cause insulin resistance, hyperinsulinemia, and research on related factors are mainly concentrated in the following aspects.

1 Free fatty acid (FFA): When obese, increased sugar-fatty acid uptake and oxidation can cause defects in glucose metabolism and non-oxidation pathways, and decreased utilization of sugar. Increased plasma FFA levels increase hepatic gluconeogenesis and The ability of the liver to clear insulin decreases, causing hyperinsulinemia. When the function of B cells can still be compensated, normal blood sugar can be maintained. After a long period of time, it leads to B cell failure, and hyperglycemia develops into diabetes.

2 Tumor necrosis factor (TNF-): It has been found that the expression of TNF- is significantly increased in adipose tissue of insulin-resistant obese patients and obese type 2 diabetic patients. The mechanisms by which TNF- enhances insulin resistance include: Accelerated fat breakdown leads to elevated FFA levels; TNF- produced by fat cells of obese people can inhibit insulin receptors in muscle tissue and reduce insulin; TNF- inhibits glucose transporter 4 (GLUT4) expression and inhibits insulin stimulation Glucose transport.

3 Peroxisome-activated proliferators (PPAR2): PPAR2 is involved in the regulation of adipose tissue differentiation and energy storage, and PPAR2 activity is decreased in severely obese individuals, which is involved in the formation of insulin resistance.

(7) Others : obesity metabolic abnormalities, increased plasma uric acid, so that the incidence of gout is significantly higher than normal people, with coronary heart disease have a history of angina pectoris, obesity serum total cholesterol, triglyceride, low-density lipoprotein cholesterol Often elevated, high-density lipoprotein cholesterol decreased, easily lead to atherosclerosis, due to venous circulation disorders, prone to varicose veins of the lower extremities, embolic phlebitis, venous thrombosis, the patient's skin may have pale purple or white lines, Distributed in the lateral side of the buttocks, the inner thighs, knee joints, lower abdomen, etc., wrinkles are prone to wear, causing dermatitis, skin sputum, and even rubbing, usually sweating more heat, low resistance and easy to infect.

Obesity check

1, blood lipid examination including cholesterol, triglyceride (triglyceride), high-density lipoprotein determination.

2, blood glucose check including glucose tolerance test, blood insulin determination.

3, fatty liver examination B ultrasound, SGPT.

4, water metabolism test antidiuretic hormone determination.

5, sex hormone determination of estradiol, testosterone, FSH, LH.

6, check blood cortisol, T3, T4, TSH, etc., in order to exclude inter-cerebral, pituitary, adrenal cortical function, thyroid function and autonomic nervous disorder.

However, attention to a series of endocrine dysfunction caused by obesity can also cause the above examination to be abnormal.

To exclude secondary obesity, consider the following tests to differentiate the diagnosis:

1. X-ray examination shows whether the saddle is enlarged and the bone is not damaged.

2, cardiovascular examination ECG, heart function, fundus and so on.

3, obese patients' routine examination items measured body weight, body mass index, obesity body type, fat percentage, B-ultrasound determination of skin fat thickness, blood pressure.

Diagnosis of obesity

diagnosis

The diagnosis of obesity is mainly based on excessive accumulation and/or abnormal distribution of fat in the body.

1. Body mass index (BMI) is a commonly used measure. Body mass index (BMI) = weight (kg) / height (m) 2, WHO proposes BMI 25 for overweight, 30 for obesity, Asia Pacific obesity and overweight The Diagnostic Criteria Symposium is based on the fact that Asians tend to have abdominal or visceral obesity when they have a relatively low BMI and show a significant increase in the risk of hypertension, diabetes, hyperlipemia and proteinuria. Therefore, BMI 23 is proposed. Overweight, BMI 25 is obese.

2, ideal weight ideal weight (kg) = height (cm) -105; or height minus 100 and then multiplied by 0.9 (male) or 0.85 (female), the actual weight of more than 20% of the ideal weight is obese; more than ideal weight 10% and less than 20% are overweight.

3, the distribution of body fat can be measured by the waist circumference or waist-to-hip ratio (WHR), the waist circumference is the distance from the midpoint between the midline of the midline of the iliac crest and the anterior superior iliac spine; the hip circumference is the most uplifted part of the buttocks. The measured distance, waist-to-hip ratio (WHR) is the ratio of waist circumference to hip circumference, waist circumference male 90 cm, female 80 cm; waist-to-hip ratio WHR > 0.9 (male) or > 0.8 (female) can be regarded as central obesity.

4, the degree of subcutaneous fat accumulation can be estimated from the thickness of sebum, 25-year-old normal shoulder thickness of the shoulder is 12.4mm, more than 14mm for fat accumulation; triceps part of the thickness of the triceps: 25-year-old male average 10.4mm, female average It is 17.5mm.

5, visceral fat B-mode ultrasound, dual-energy X-ray absorptiometry, CT scan or magnetic resonance measurement, after determining obesity, should be identified as simple obesity or secondary obesity.

Differential diagnosis :

Obesity can be combined with medical history, body film and laboratory data to identify simple secondary depression, such as high blood pressure, central obesity, purple lines, amenorrhea, etc. with 24-hour urine 17-hydroxysteroids Those who should be considered for hypercortisolism, those with low metabolic rate should further check T3, T4 and TSH and other thyroid function tests. In addition, it is often necessary to pay attention to whether there is diabetes, coronary heart disease, atherosclerosis, gout, cholelithiasis. And other diseases.

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