Obesity pathology

2021-01-27 12:00 AM

Recently, the drug was added to the list of causes of obesity factors, because of increased pharmacotherapy. Weight gain can be a product of the hormone steroids

Define

Obesity is defined by an excess of body fat, especially related to energy metabolism, with negative consequences for health.

Or it is called obesity with an increase of more than 25% of body weight and is evaluated based on size and sex.

The vast majority use the BMI formula to assess obesity. A BMI of 20-25kg / m2 is considered good, overweight when BMI is> 27kg / m2 and according to the currently accepted international classification, obesity is defined by BMI (30 kg / (m2). From this value, it is seen as excessive fat accumulation, because it entails a significant increase in morbidity and mortality.

Epidemiology

Obesity is increasing, especially in economically developed countries around the world; Especially in the last 10 years, the highest meeting age is> 30 years old. The frequency of obesity depends on diagnostic criteria. The prevalence of obesity varies with age, sex and geography, race, and socioeconomic status:

Age: 2% at 6-7 years old, 7% at puberty, and highest at the age (50 (Europe America)).

Gender: N ữ met more men (25% against 18%).

Geography, race: Eastern France is 33%, Western is 17%. In South Africa, obesity is more common in southern provinces than in northern provinces. Over the past decade, the obesity rate of the entire United States has ranged from 25 to 33%, up one third. Black women aged 45-55 years are twice as likely to be obese than white women of the same age.

In Europe, there have been about 15 recent epidemiological studies on quantitative overload in 17 European countries. The use of diagnostic criteria varied according to the study (BMI, or Lorentz formula, or Broca formula).

Social and economic conditions related to nutrition regime and lifestyle:

In China, the number of obese children has increased in recent years, due to being pampered and overeating, since the policy of having only one child per family;

In Singapore, there is a marked increase in obesity among children in primary schools.

In Ho Chi Minh City, due to the rising standard of living, the number of obesities in children and adults is increasing.

But in the US, when the socioeconomic level is low, the prevalence of obesity is higher than the high socioeconomic standard of living.

Obese adults have a 50-100% risk of premature death compared to people with a BMI of about 20-25 kg / m2.

Whole disease

Calorie overload

In terms of metabolism, obesity is due to excess calories exceeding the body's needs. However, there are individual differences in energy use and muscle needs. There are patients who eat a lot but not fat, the reason is unknown, because in a family, the same diet, but there are people who are thin and fat. This suggests a genetic predisposition to obesity.

Eat a lot

Excessive needs is often the cause of obesity (95%). Overeating due to many reasons:

Familiar habit: explain many people are obese in a family, regardless of genetics.

Mental illness.

Decreased physical activity without eating less: seen in the elderly or less active.

Genetic causes

69% of obese people have an obese parent; 18% of both parents are obese, only 7% have a family history of obesity.

According to Mayer J. (1959), if both parents are normal, 7% of their children will be obese. If either person is obese, 40% of their child is obese. But if both parents are obese, the child obesity rate is 80%.

The distinction between the role of genetics and the role of nutrition remains unclear. Genetics are dominant and genetic factors make the ability to divide fat cells more easily.

Endocrine causes

Cushing's syndrome: Distribution of fat in the face, neck, abdomen, while limbs are small.

Hyper insulin: Because pancreatic tumours secrete insulin, increase appetite, eat more and regenerate fatty tissue, increase glucid digestion.

Hypothyroidism: Rarely, it must be noted that basal metabolism, expressed in calories / m2, of the skin surface is usually decreased in obese people. Indeed, the increased skin surface appearance is due to an increase in adipose tissue, which is less oxygen-consuming tissue. In contrast, in most other obesity cases, this primary reduction in metabolism is not of thyroid origin.

Obesity-genital syndrome (Froehlich or Babinski-Froehlich syndrome): obesity of the trunk and extremities and hypogonadism, manifested in adolescents with cessation of genitals, may include other disorders such as diabetes mellitus, visual and mental disorders. According to A. Froehlich the cause is a hypothalamus tumour.

Castor: fatty tissue increases around the groin, high in the thighs, resembling genital obesity syndrome

Alcohol is an important source of energy.

The cause is drug

Recently, the drug was added to the list of causes of obesity factors, because of increased pharmacotherapy. Weight gain can be a product of the hormone’s steroids and four main groups of psychostimulants:

Classic antidepressant (tricyclic, quadruple, inhibited IMAO).

Benzodiazepine.

Lithium.

Antipsychotic medicine.

So, limiting the use of psychostimulants to prevent weight gain may reduce therapy.

Pathophysiology

Distribution and progression of fat mass in 2 sexes

In children <15 years old, fatter and predominance in the lower and peripheral body, boys and girls alike, but in girls, fat more than 1.5 times than men.

During puberty: Women are 2 times fatter than men. No change in fat distribution until age 50. After age 50, the fat tends to stay higher and deeper in the body. This improvement is evident in men aged 15-20 years.

Sjostrom and Kvist found that at the level of the pathway across the umbilical line, L4-L5 plate, 53% fat above this line in men, respectively; 46% in women. Visceral fat 9 - 34% in men and 4-14% in women. This distribution is general for the majority of patients, but in a few cases, this fat distribution is more or less contradictory.

Hormone role in the mechanism of fat distribution

Androgens reduce the number of fat cells in the lower body part.

Cortisol increases the fat cell volume in the upper part.

Oestrogen and possibly progesterone increases fat cell volume and number

In rare cases due to impaired sex hormone production and/or transport, for the remainder, sex hormone sensitivity to fat cells is the main cause of fat distribution in the sexes. This phenomenon is genetically dominant.

Different properties of male fat and female fat

Respond to male and female fat cells differently. Many studies by Lafontan have shown that adrenergic activity is superior to male fat cells, the anti-fat activity of (-2 adrenergic predominant on female fat cells. Lipoprotein lipase enzyme increases in female fat, maximum during pregnancy, minimum during lactation.

Insulin resistance in muscle, adipose tissue during obesity in rats

Animal obesity, genetic or experimental causes; as well as obesity in humans, often leads to insulin resistance combined with hyperinsulinemia and with normal or elevated blood glucose. This insulin resistance is found experimentally at the level of the hormone's primary target cell, muscle tissue, and adipose tissue. The adipose tissue first reacts normally to insulin before insulin becomes resistant. This pattern of progression is similar in both genetic obesity and obesity caused by overeating.

Increased basal metabolism

In obese people, the lean mass (ie the mass of meat, which is the most toxic of basal metabolism) is significantly higher than the lean mass in a normal weight person, so in obese people, there is Excessive energy is involved in radical metabolism.

Reduce heat generation

Heat generation due to the net secretion regime in obese people is lower than in normal-weight people.

The consequences of two paradoxical changes in energy metabolism suggest that in obese people, overall energy consumption is only marginally above the average of the average human energy consumption.

Eat a lot

Indeed, to a certain extent, the balance phase, energy input equals energy consumption.

Hereditary factors of obesity

One-third of obesity is inherited. Not genetic; According to families with the participation of environmental factors, there are more than one-third of cases. The third remaining factor is the non-contagious environment

Gene is obese

Leptin gene is a protein, encoded by the ob. gene found only in white adipose tissue. Lack of this protein will cause metabolic abnormalities in rats (obesity, increased insulin, increased blood sugar, decreased body temperature). The hypothesis is that Leptin may inhibit eating attitudes across the hypothalamus. Many studies show that leptin is most produced by adipose tissue during fasting and during experimental diabetes, and also returns to normal within hours after eating or injecting insulin. This showed that Leptin acted as a signal of boredom.

On the other hand, in ob. / ob. mice, adding Leptin resulted in a significant loss of weight. Leptin also peaks the absorption of food, blood sugar, and blood insulin. It increases overall metabolism, body temperature and level of physical activity. Furthermore, Leptin also acts on normal animals and can lose 12% of its body weight and all its fat within 4 days.

In obese patients, gene ob. is highly increased. This increase is proportional to the body weight. It is noteworthy that in women, Leptin is secreted in additional levels to regulate hormones. It is clear that obesity is not caused by decreased Leptin synthesis, nor is it due to abnormal Leptin. According to Catherine Le Stunff et al., In obese people, Leptin increased 10 times higher than the amount of Leptin in normal people and proportional to fat mass. The increase in Leptin did not reduce appetite in obese people but continued to increase overeating and increase weight gain, which underpins the argument that there is Leptin resistance in obese people.

Symptom

Lorentz

Calculate ideal weight (TLLT) mainly based on height.

TLLT (men) = height - 100-or TLLT (female) = height - 100 -Ġ

If TLLT increases> 25%, it is obesity.

Or IC = (TLHT / TLLT) (100%. (Actual weight / ideal weight) If IC => 120% - 130%: Excessive weight gain

If IC => 130% obese.

BMI

(Body Masse Index = Body Mass Index): Weight (kg) / height (m2).

According to the International Obesity Task Force 1998

Weight gain when BMI = 25 - 29.9; Obesity when BMI (30.0

According to the obesity diagnostic standards applicable to Asians: obese on BMI (25

Measure the thickness of the triceps

In the middle of the distance from the elbow and shoulder, an average of 16.5mm in men, 12.5mm in women.

Obesity may have no symptoms

Or have difficulty breathing, fatigue, hot discomfort, digestive disorders, osteoarthritis due to overloading the body (hip joints, thighs, lumbar spine).

Lipide metabolism disorders

Increase lipoprotein (type VLDL, LDL).

The psychoactive consequences of obesity can be severe

L o deposited with hypertension.

Reduced blood glucose tolerance

Type 2 diabetes mellitus (metabolic syndrome).

Severe obesity

Hyperventilation (Pickwick's syndrome), heart-lung failure.

Evaluation methods

There are many methods of assessing adipose tissue (obesity): clinical anthropometries, new ultrasonic imaging methods, even density tomography (tomodensitométrique). The choice between these different methods depends on the context and the goal of the study.

Anthropometric measurement method

Body Mass Index (BMI): Results as outlined above in the symptom section.

Lorentz formula: To calculate an ideal weight (TLLT), this formula is based on the patient weight in kg and height in cm as stated above:

Skin-fold thickness: The thickness of the skin fold reflects the thickness of the subcutaneous fat, measured with a Harpender or Holtane compass, with a wide handle, with constant engraved.

How to measure: The left hand holds the compass, then clamps the vertical skin fold between the index finger and the thumb, the ruler will indicate the thickness of the skin fold.

Measurement of skinfold thickness in a variety of locations is necessary: ​​points around the base of the arms and thighs, biceps, triceps, on the shoulder blades, on the pelvis, epigastric, median, and lower. In contrast, in women, the skin folds of the thighs and hypotenes are thicker than the skin folds above the navel and upper arms.

Example: Measure the thickness of the triangular fold in the middle of the distance from the elbow and the shoulder, average of 16.5mm in men, 12.5mm in women.

Index of fat distribution in skin folds (Assessment of adipose tissue distribution): Various indicators or methods have been proposed: measuring the thickness of skin folds significantly reflects the subcutaneous fat layer, only to give 2 readings that are easier to measure

Fat-muscle index of Jean Vague:

The arm-thigh muscle fat index (CSWT) consisted of the thickness of the skin folds around the base of the arm and thigh, although the circumference of the thigh was measured to the same extent. IWT allows to evaluate the amount of fat and muscle distribution between the Delta and thigh muscles but is not directly related to the abdominal fat layer.

The normal value of IWT in women of normal weight is 0.76 - 0.8, and for men 1.01 - 1.10. Jean Vague was able to define various forms of the hypergynoide, gynoide, mixte, androide, and hyperandroide distributions.

Delta fat-muscle thickness index and trochantérien: The index between Delta adipose tissue thickness and posterior displacement is less sensitive to the underlying muscle layer. 0.7 in men, and 0.3 in women.

Measure the circumference:

Fat mass distribution index in the circumference.

Arm-Thigh Index: Measuring forearm and thigh circumference at the base is easy to do. This is a reliable indicator of fat distribution. The ratio of arm circumference to thigh circumference at base: 0.58 in men and 0.52 in women.

Waist / Waist circumference: The figure of waist circumference / waist circumference was proposed by M. Ashwell as a reliable measure of fat distribution. Normal values ​​are 0.92 - 0.95 in men; 0.75 - 0.80 in women. Obesity in men when VB / VM> 0.95 and female> 0.80. Or according to ATP III, the male waist is <102 cm, the female is> 88 cm

Supersonic

The thickness of shallow adipose tissue can be directly accurately measured by placing the probe perpendicular to the skin surface, without pressure, at the desired point. The technique can clearly differentiate the limit of fat, muscle and bone.

Density tomography

This method has recently been applied to evaluate the fat distribution. It can quantify fat distributed under the skin and around the viscera. From the cross-section of the scanner, it is possible to compute the displacement surface of adipose tissue. The advantage of this approach can be to determine the deep adipose tissue surface around the viscera. The cross-section L4-L5 will allow to accurately distinguish the difference in fat distribution between the sexes. The evaluation by this method gives reliable and accurate results, however, the technical cost is expensive and the heavy tools are difficult to implement at normal routes.

Impedance meterrie: Due to the percentage of existing body fat and the ideal amount of fat based on weight, height, sex, then calculate the percentage of fat overload.

Classification of obesity

Sort by age

Obesity occurs in adulthood: (hypertrophic form) a fixed number of fat cells and weight gain is due to the accumulation of too many lipids in each cell, and glucide-lowering therapy is effective.

Childhood obesity: (hypertrophic hyperplasia) not only hypertrophy cells but also increase in number, difficult to treat.

Male and female obesity is based on fat distribution

Male obesity (androide): most common in men, predominantly in the upper part of the body, on the navel, nape of the neck, shoulders, chest, abdomen, and belly above the navel.

Female obesity (gynoide): common in women, predominantly below the navel, groin, thighs, buttocks and lower legs.

Common obesity is androide obesity in women.

Classification based on waist circumference (VB / VM)

Measure waist circumference/hip circumference in the position described in section VI (Obesity Assessment Methods). Obesity in men when VB / VM> 0.90; obesity in women when VB / VM> 0.85.

Based on the Lorentz formula

IC = (TLHT / TLLT) (100%. (Actual weight / ideal weight) If> 120% - 130%: overweight gain.

If> 130%: obese.

Based on BMI

Table: International Obesity Task Force 1998:

Classify

BMI (kg/ (m2)

Risk

Thin

Normal

Weight gain

Fat

Grade II

Grade II

Grade III

18,5

18,5 - 24,9

25 - 29,9

≥ 30.0

30,0 - 34,9

35,0 - 39,9

≥ 40

Moderate increase

Clearly increased

Moderate or general obesity

Severe obesity

Excess obesity or obesity disease

Currently, in order to apply in accordance with regional characteristics through practical research in Asian countries, WHO has officially agreed that Asian countries have adopted the February 2000 standard as a diagnostic standard. fat.

Symptoms

The risk of overweight or obesity is causing many illnesses that even appear very early and cause death, such as smoking.

Many studies show that there is a very significant correlation between male and male obesity

metabolic complications such as diabetes, hyperlipidaemia, atherosclerosis, gout.

Complications of obesity

Excessive weight gain.

Weakened functional state.

Hypertension.

Diabetes.

Coronary artery disease, biliary tract, gout.

Sleep apnoea, deep embolism, pulmonary embolism.

Osteoarthritis, pressure ulcers.

Female: K bowel, breast, vertebrae, ovaries.

Male: K colon, prostate.

Metabolic complications

Glucide metabolism: insulin resistance, increased insulin secretion, found by oral glucose tolerance test are disturbed, easily leading to diabetes, so obesity is a risk factor for diabetes. Street.

Lipid metabolism: plasma triglycerides often increase in obesity, increases VLDL. The lipoprotein elevation is related to the above disorders of glucide metabolism, causing the liver to produce more VLDL. Blood cholesterol is rarely directly affected by obesity; but if there is a previous increase in cholesterol, it is easy to increase LDL. HDL usually decreases with increased triglycerides.

Uric acid metabolism: Blood uric acid is often increased, perhaps related to hypertriglyceridemia. Attention should be paid to the sudden increase in uric acid during treatment to lose weight, which can cause acute gout attacks (due to Protide degradation).

Cardiovascular complications

Obesity is one of the risk factors for cardiovascular disease such as:

Hypertension (THA): strongly associated with obesity and increased blood pressure, the frequency of hypertension increases in obesity regardless of male or female. Blood pressure drops with weight loss. Mechanism of hypertension in obesity is not completely clear, besides atherosclerosis, which is common, there is also a hypothesis due to increased blood insulin and insulin resistance, increased sodium absorption in the renal tubules and increased secretion of catecholamine causing vasoconstriction.

Other complications such as left heart failure, stroke.

Complications in the lungs

Decreased lung function due to poor chest mobility due to overweight.

Pickwick syndrome: Sleep apnoea.

Increased red blood cells, increased blood CO2.

Complications of bones and joints

At high-pressure joints (knee, hip, spine), it is easy to experience pain and degeneration.

The frequency of femoral head anaemia necrosis is increased. Disc herniation, spondylolisthesis is common.

These complications increase in menopausal women.

Endocrine complications

Increased blood insulin and insulin resistance and type 2 diabetes, due to the effect of beta-endorphin or a decrease in the quantity and quality of insulin, stimulates beta cells by eating more glucide.

Sexual endocrine function: decreased fertility. Long menstrual cycle without ovulation. Hirsutism.

Other complications

The risk of cancer increases: cancer of the uterus, breast, colon, prostate.

Complications aggravated by obesity:

Hepatobiliary: Gallstones, fatty liver.

Kidney: Renal venous obstruction, proteinuria.

Obstetrics: Pregnancy toxicity, difficulty giving birth, increased caesarean section.

Skin: Stretchy skin, interstitial yeast, hyperkeratosis of the soles of the feet, hands.

Treatment

The obesity treatment model: is based on the following 3 main ways:

Weight reduction.

Increase in energy consumption (Exercise).

Change in food metabolism.

Approaches 1 and 2 include energy-saving and exercise.

Lose weight and exercise

Weight loss is the primary goal of treatment, with a slight weight loss of between 5% and 10% of the baseline weight, with real-life and exercise also clinically significant improvements, and hypertension., abnormal lipids as well as blood glucose. About 80% of type 2 diabetic patients have weight gain or obesity, if weight loss is from 5% to 10%, there is a significant improvement in HbA1c.

According to "Finnish Diabetes Program" and "Diabetes Prevention Program" showed that patients with impaired blood glucose tolerance, if weight reduction by about 7% will reduce the risk of type 2 diabetes by 58%.

Lose weight:

Weight loss diet: The first and widely used method. The main way is to reduce calories, reduce fat and some other foods that reduce energy production for the body. If the energy input is lower than a physiological requirement, the additional energy comes from stored adipose tissue. The big difference between energy intake and input requirements is due to hunger. In the absence of feed, the energy withdrawn from the stored adipose tissue is 1500-3000 kcal. Body fat contains 7500 kcal/kg. With a negative caloric balance of 1500 kcal / day, there is a decrease in body weight by 1 kg every 5 days. Weight loss ranges from 0.5-1 kg/week are suitable for a real weight-loss session.

For the elderly medium, 1200 kcalo / day maintenance lose> 0.5 kg / week.

In general, calories per patient are best based on their current weight. Save calories when caloric intake is 20-25 Kcalo / kg/day

Thus, if the number of calories provided decreases below 500 Kcalo / day, it will reduce weight loss by about 0.5 kg/week. Treatment success depends on the patient's age (teenage obesity must be treated very early) and the patient's motivation that is essential for treatment. For patients with a habit of overeating, accepting food restriction throughout life is difficult.

Saving less fat, reducing foods rich in carbohydrates and secreting monounsaturated fats improves coronary artery disease. Eat plenty of fruits, vegetables, and whole grains, rich in fibre. Replace low-nutrient, high-calorie foods with high-nutrient, low-calorie foods

To avoid heart disease, eat vegetables, fruits, whole grains, fish and low-fat processed foods with exercise.

The following is the baseline of the Therapeutic Lifestyle Change (TLC) (TLC), a 12-week program followed by every 2 weeks for a half-three-month period. replace every 6 weeks to achieve triglyceride, HDL-C and normal NPDNGU. Each visit assesses the LDL-C concentration, waist circumference, weight, and assesses the patient's compliance with real energy and exercise.

Providing adequate trace elements, effective glucide reduction, good weight loss, no complications

Treatment of fasting:

Dangerous and hospitalized (obesity is difficult to treat). Fasting causes catabolism of fatty tissue and proteins. Reduces sodium and can cause serious liver damage.

Physical activity and exercise:

Physical activity and exercise, which increases energy consumption, are the primary treatment for overweight and obese patients, are considered key factors in weight loss programs.

The purpose of fitness training is to the following advantages:

Improved blood sugar.

Decreased insulin resistance, increased peripheral insulin sensitivity.

Lose weight.

Improving lipoprotein (reducing triglycerides, total cholesterol, LDL- Cholesterol and VLDL, Increasing HDL- Cholesterol), should reduce atherosclerosis.

Beneficial cardiovascular effects (maximized oxygen utilization, slowing resting and exercise heart rate, a moderate reduction in BP, reduced risk of embolism, and reduced mortality from coronary artery disease).

During physical activity, the heart rate is about 50% of the maximum heart rate. The maximum heart rate is calculated using the following formula: (220-years) / 2. For example, a 50-year-old patient: 220 - 50 = 170 / minute, the allowable heart rate is 85 times / minute.

Increase energy.

Increases toughness.

As a strategy to help obese people lose weight, exercise is a great way anyway, Exercise increases the body's energy consumption, but also increases appetite. Walking 5 km increases energy consumption

200 calories. In fact, if energy consumption does not increase, weight loss is difficult because it is difficult to maintain a reduction in feed intake.

Should gradually increase physical activity such as exercise 10-30 minutes/day until reaching 300 minutes/week.

According to Surgeon General's Report on Physical Activity and Health, it is recommended that all ages exercise for an average of 30 minutes/day, such as running 30 minutes, 3 times a week, but recently it is better to recommend 60 minutes/day. day.

According to Bethesda, should exercise about 2 and a half hours/week, eat fat, and lose weight is to reduce the rate of diabetes in the US.

After the exercise is complete, insulin effects increase and last for many hours. Under the influence of insulin, the liver and muscles take in glucose and restore glycogen.

Physical activity is usually walking, cycling or swimming.

To burn 100 calories (about 10 grams of fat) it takes 20 minutes to walk, 12 minutes to swim or tennis, 8 minutes to cycle or jog.

However, exercise does not do well for people who are too fat, with heavy body movements and therefore sweating easily and often joint pain, in addition to severe cardiovascular disease also limits exercise.

But there are also many cases, with real and exercise still does not lose weight and is called incurable fat. So fatback is usually very general. This is why people take drugs and have surgery.

Obesity drugs

After 12 weeks of real-time, lose weight and exercise without improvement

You can use the drug by weight.

Adrénergique receptor modulators (Diethylpropion, Mazindol, Phentermine) or serotonin (Fenfluramine) receptors:

All drugs have side effects, loss of appetite, loss of weight, and should be used only after weighing the pros and cons of this treatment. These drugs used in combination with better results than used alone, such as the combination of Fenfluramine with Phentermine (noradrenergic). However, in 1997 there was a sign of valvular heart disease in a woman, so 1998 Fenfluramine and Dexfenfluramine withdrew from the market, leaving only Phentermine.

Drugs that increase energy consumption:

Thyroid hormone (L-Thyroxin group), but no frequent action, is rarely used because prolonged suppression of thyroid function or hypothyroidism.

The drug has the effect of converting nutrients:

Drugs that reduce food digestion (lipase inhibitors) or alter metabolism (androgen, oestrogen, GH)

Currently, there are 2 drugs approved by the "US Food and Drug Administration / FDA" and WHO only for prolonged weight loss, Sibutramine (Meridia *, Reductil *) and Orlistat (Xenical *).

Reductil treatment (10 mg/tablet) can help reduce (2 kg within a month and 4.4-6.3 kg after 6 months, Reductil does not cause anorexia, does not depend on drugs but makes patients have colds. The feeling of fullness makes them eat less, so it is suitable for those who are always hungry and have a lot of appetites, Reductil also reduces the VB / VM ratio, reduces blood lipids and blood glucose. dry mouth, constipation, mild headache, palpitations, hypertension in some people (rare) Caution: not for people with hypertension and coronary artery disease CCD: children, drug hypersensitivity, Pregnancy, lactation.

Sibutramine is a selective inhibitor of the re-capture of both serotonin and norepinephrine, it reduces the palatability threshold (due to the central effect of making the patient feel full early) and increases thermogenesis, decreases metabolic rate. should reduce weight.

Orlistat inhibits pancreatic lipase, reduces intestinal absorption. Side effects are fat malabsorption, reduction of oil micro admin such as vitamins D and E, so it is necessary to increase the vitamin.

Drugs that lose appetite.

Surgery:

The only exception applies to extreme, life-threatening obesity (> 50% of ideal weight in patients <40-50 years of age).