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OBESITY.

OBESITY

• significant public health crisis in the United States and the rest of the developed world.

• The problem is also increasing rapidly in numerous nations worldwide.

OBESITY TREATMENT

• The cost of obesity management in the United States alone amounts to approximately $100 billion annually, of which approximately $52 billion are from the direct costs of health care.

OBESITY

• These costs amount to approximately 5.7% of the entire US health spendings. The cost of lost productivity due to obesity amounts to approximately $3.9 billion, while another $33 billion is spent on various weight loss products and services.

OBESITY

Obesity represents a state of excess storage of body fat.

Overweight is usually defined as an excess body weight for height.

While adult men have a body fat percentage of 15-20%, women have a higher proportion (approximately 25-30%).

OBESITY

Because differences in weight among individuals are only partly due to body fat variations, body weight is a rather limited, although easily obtained, index of obesity.

OBESITY

• Other indices used to estimate the

distribution of obesity include the 4

standard skin thicknesses (ie, subscapular,

triceps, biceps, suprailiac) and various

anthropometric measures, of which waist

and hip circumferences are the most

important.

OBESITY

• Surgical literature ( different classification) for recognize severe obesity.

• BMI greater than 40 kg/m2 (severe obesity)

• BMI of 40-50 kg/m2 (morbid obesity) • BMI greater than 50 kg/m2 ( super

obese)

Obesity Pathophysiology:

• The cause of obesity is an imbalance between energy intake and energy output.

Obesity Pathophysiology:

• obesity obviously is far more than the result of excess eating and/or too little exercise.

• in USA, 22% of adults and 25% of adolescents report significant regular physical activity.

• 25% of adults in the United States report no significant physical activity during leisure

• 14% of adolescents have similar reports of inactivity.

Obesity

• Two major groups of factors with a balance that variably intertwines in the development of obesity are genetics, which is presumed to explain 40-70% of the variability in obesity variance, and environmental factors.

Obesity

• The high prevalence of obesity in the children of parents who are obese and the high concordance of obesity in identical twins suggest a significant genetic component to the pathogenesis of obesity, the trends of the last few decades, which are simular with recent changes in dietary habits and activity, also suggest a significant role for environmental factors.

Leptin

• Leptin was discovered in 1994 by Friedman et al and ushered in an explosion of research and a great increase in knowledge about regulation of the human feeding and eating cycle.

• The major role is to, reduce dietary intake and fat storage while modulating energy expenditure and carbohydrate metabolism to prevent further weight gain.

Monogenic models for obesity in humans and experimental

animals

• The various available monogenic models have greatly increased our knowledge about mechanisms for the development of obesity, and they also have provided multiple potential targets for future antiobesity medications.

• Of particular interest is the fact that patients with POMC mutations, because of the deficiency in MSH production that results, tend to have red-colored hair. Also, because of their diminished adrenocorticotropic hormone (ACTH) levels, they tend to have central adrenal insufficiency.

• Some recent data suggest that as many as 5% of children who are obese have MC4 or POMC mutations. If confirmed, these would be the most common identifiable genetic defects associated with obesity in humans.

• In the same line as the evidence that proved Helicobacter pylori as the cause for peptic ulcer disease, some evolving data suggest that a significant inflammatory and possibly infective etiology may exist for obesity. Adipose tissue is known to be a repository of various cytokines, especially interleukin-6 and tumor necrosis factor-alpha

• Some data have shown that adenovirus 36 infection is associated with obesity in chickens and mice.

• Other data also suggest that while humans who are not obese have a 5% prevalence rate of adenovirus 36 infection, humans who are obese have a prevalence rate of 20-30%.

Frequency:

• 100 million adults in the United States are at least overweight or obese.

• 35% of women and 31% of men older than 19 years are obese or overweight.

• The prevalence of obesity in children in the United States has increased markedly between the time of the National Health and Nutrition Examination Survey (NHANES) 2 and 3 trials.

• 20-25% of children are either overweight or obese, and the prevalence is even greater in some minority groups, including Pima Indians, Mexican Americans, and African Americans.

• Internationally: The prevalence of obesity worldwide is increasing, and this is particularly occurring in the developed nations of the Northern Hemisphere, including the United States, Canada, and most of Europe.

• Available data from the MONICA (monitoring cardiovascular) disease study in Europe suggest that at least 15% of men and 22% of women in Europe are obese.

• Similar data now are being reported from many developing countries, particularly in Asia and, to a lesser extent, in Africa.

• Reports from countries such as Malaysia, Japan, Australia, New Zealand, and China detail an epidemic of obesity in the last 2-3 decades.

• Data from the Middle Eastern countries of Bahrain, Saudi Arabia, Egypt, Jordan, Tunisia, and Lebanon, among others, exhibit this same disturbing trend, with alarming levels of obesity often exceeding 40%, particularly worse in women.

• Data from the Caribbean and South America also highlight similar trends. While data from Africa on this issue are scant, a clear and distinct secular trend of profoundly increased BMIs clearly exists when people from Africa immigrate to northwestern hemispheric countries. Studies comparing these indices among Nigerians residing in Nigeria and recent immigrants to the United States show this trend very poignantly.

• Conservative estimates suggest that as many as 250 million people (approximately 7% of the estimated current world population) are obese.

• Mortality/Morbidity:

• Data available from insurance company databases and large prospective cohorts such as the Framingham and NHANES studies clearly indicate that obesity is associated with a significant increase in both morbidity and mortality.

• The degree of obesity (generally indicated by the BMI) at which a discernible increase in mortality occurs is, however, higher for African Americans and Hispanic Americans than for white Americans, suggesting a significant racial spectrum and difference in this effect.

• Race: • Obesity is a cosmopolitan disease that affects all races

worldwide. • However, certain ethnic and racial groups appear to be

particularly predisposed.• Pima Indians of Arizona and other ethnic groups native to

North America have a particularly high prevalence of obesity.

• Polynesians, Micronesians, Anurans, Maoris of the West and East Indies, African Americans in North America, and the Hispanic populations (both Mexican and Puerto Rican in origin) in North America also have particularly high predispositions to developing obesity.

• Secular trend studies clearly underline the marked importance of environmental factors (particularly dietary issues) in the development of obesity. Many of the genetically similar cohorts of the above named high-risk ethnic and racial groups have far less prevalence for obesity in their countries of origin, but this changes significantly when such groups have immigrated to the affluent Northern Hemisphere, with altered dietary and activity habits. These findings form the core concept of the thrifty gene hypothesis espoused by Neal et al.

Sex:

• No significant sex difference exists in the prevalence of obesity.

Age:

• The prevalence and age distribution of obesity has changed significantly in the last 2-3 decades.

• While the prevalence has remained at 30-50% of the adult population in the United States, the prevalence in children has increased to 15-25%.

• Physical:

• In the clinical examination, include measurement of the anthropometric parameters and the standard detailed examination required for the evaluation of persons with any chronic multisystemic disorder such as obesity.

• Causes: The etiology of obesity has many facts. Among the facts to be considered in the development of obesity are the following:

• Metabolic factors

• Genetic factors

• Level of activity

• Behavior

• Endocrine factors

• Race, sex, and age factors

• Ethnic and cultural factors

• Socioeconomic status

• Dietary habits

• Smoking cessation

• Pregnancy and menopause

• Psychologic factors

– Screening with a serum thyrotropin level usually is sufficient. Importantly, hypothyroidism itself rarely causes more than mild obesity.

• For screening purposes, 24-hour urinary free cortisol– This test only needs to be performed when

Cushing syndrome or other hypercortisolemic states are clinically suspected.

– Approximately 4% of patients with Cushing syndrome have normal urinary free cortisols.

• Fasting glucose and insulin

– Obesity is associated with insulin resistance, even though these levels are normal in a significant proportion of subjects who are obese.

– In other people, insulin levels may be elevated.

– In those with impaired glucose tolerance, the fasting serum glucose level is elevated to higher than 110 mg/dL.

• Procedures:

• Among the various procedures relevant to the management of patients who are obese are procedures to estimate the degree of visceral and subcutaneous fat. These include the standard anthropometric measurements and caliper-derived skin thickness estimates.

• Medical Care: While obesity in itself is associated with increased morbidity and mortality, massive poorly monitored weight loss and/or weight cycling can have equally bad consequences. Among the two most important potential complications to watch out for in the setting of weight loss are eating disorders and binge eating.

3 major phases of any weight loss program

• (1) preinclusion screening phase

• (2) definitive weight loss program

• (3) maintenance phase, which conceivably can last for the rest of the subject's life, but must last for at least 2 years after the weight loss program is completed.