Risk factors ,complications and management of obesity

This powerpoint describes the consequences of obesity and its management.

1. OBESITY DR.K. INDIRA DEVI M.D.,
PROFESSOR, DEPARTMENT OF GENERAL MEDICINE

2. DEFINITION OF OBESITY Obesity is a state of excess adipose tissue mass. Although often viewed as equivalent to increased body weight, this need not be the case—lean but very muscular individuals may be overweight by numerical standards without having increased adiposity. Obesity is therefore defined by assessing its linkage to morbidity or mortality.

3. Measurement Of Obesity Although not a direct measure of adiposity, the most widely used method to gauge obesity is the body mass index (BMI), which is equal to weight/height2(in kg/m2). Others include anthropometry (skinfold thickness), densitometry (underwater weighing), computed tomography (CT) or magnetic resonance imaging (MRI), and electrical impedance. BMIs for the midpoint of all heights and frames among both men and women range from 19 to 26 kg/m2. BMI of 30 is most commonly used as a threshold for obesity in both men and women.

4. BMI between 25 and 30 should be viewed as medically significant therapeutic intervention in the presence of risk factors that are influenced by adiposity, such as hypertension and glucose intolerance. Intraabdominal and abdominal subcutaneous fat have more significance than subcutaneous fat present in the buttocks and lower extremities.

5. Nomogram for determining body mass index

6. PHYSIOLOGIC REGULATION OF ENERGY BALANCE Body weight is regulated by both endocrine and neural components that ultimately influence the effector arms of energy intake and expenditure. Body weight regulation or dysregulation depends on a complex interplay of hormonal and neural signals. Permitting obesity to develop when food is abundant and physical activity is limited. Major regulator of these adaptive responses is the adipocyte-derived hormone leptin, which acts through brain circuits to influence appetite, energy expenditure, and neuroendocrine function.

7. Appetite is influenced by many factors that are integrated by the brain, most importantly within the hypothalamus.

8. ADIPOCYTE AND ADIPOSE TISSUE Adipose tissue is composed of the lipid-storing adipose cell and a stromal/vascular compartment. Adipose mass increases by enlargement of adipose cells through lipid deposition, as well as by an increase in the number of adipocytes. Adipocyte has generally been regarded as a storage depot for fat, it is also an endocrine cell that releases numerous molecules in a regulated fashion.

9. FACTORS RELEASED BY ADIPOCYTE

10. ETIOLOGY OF OBESITY At one level, the pathophysiology of obesity seems simple: a chronic excess of nutrient intake relative to the level of energy expenditure. However, due to the complexity of the neuroendocrine and metabolic systems that regulate energy intake, storage, and expenditure, it has been difficult to quantitate all the relevant parameters e.g., food intake.

11. ROLE OF GENES VERSUS ENVIRONMENT Environment plays a key role in obesity, as evidenced by the fact that famine limits obesity in even the most obesity-prone individual. Specific genes are likely to influence the response to specific diets, but these genes are largely unidentified. Both epidemiologic correlations and experimental data suggest that sleep deprivation leads to increased obesity.

12. SPECIFIC GENETIC SYNDROMES

13. The physiologic system regulated by leptin

14. Central pathway through which leptin acts to regulate appetite and body weight

15. HYPOTHYROIDISM The possibility of hypothyroidism should be considered, but it is an uncommon cause of obesity. Much of the weight gain that occurs in hypothyroidism is due to myxedema . INSULINOMA Patients with insulinoma often gain weight as a result of overeating to avoid hypoglycemic symptoms

16. CRANIOPHARYNGIOMA AND OTHER DISORDERS INVOLVING THE HYPOTHALAMUS Whether through tumors , trauma, or inflammation, hypothalamic dysfunction of systems controlling satiety, hunger, and energy expenditure can cause varying degrees of obesity . Growth hormone (GH), which exerts lipolytic activity, is diminished in obesity. Despite low GH levels, insulin-like growth factor (IGF) I (somatomedin) production is normal, suggesting that GH suppression may be a compensatory response to increased nutritional supply.

17. PATHOGENESIS OF COMMON OBESITY Obesity can result from increased energy intake, decreased energy expenditure, or a combination of the two. Measurements of chronic energy expenditure are possible using doubly labeled water or metabolic chamber/rooms. When fat stores are depleted, the adipostat signal is low, and the hypothalamus responds by stimulating hunger and decreasing energy expenditure to conserve energy. Conversely, when fat stores are abundant, the signal is increased, and the hypothalamus responds by decreasing hunger and increasing energy expenditure.

18. A Comparison of Syndromes of Obesity—Hypogonadism and Mental Retardation

19. PATHOLOGIC CONSEQUENCES OF OBESITY Insulin Resistance and Type 2 Diabetes Mellitus Hyperinsulinemia and insulin resistance are pervasive features of obesity. Insulin resistance is more strongly linked to intraabdominal fat than to fat in other depots. Major factors include: Insulin itself, by inducing receptor downregulation . Free fatty acids that are increased and capable of impairing insulin action.

20. 3.Intracellular lipid accumulation. 4.several circulating peptides produced by adipocytes, including the cytokines TNF-α and IL-6, RBP4, and the “ adipokine ” adiponectin, which have altered expression in obese adipocytes and can modify insulin action. Obesity, however, is a major risk factor for diabetes, and as many as 80% of patients with type 2 diabetes mellitus are obese. Weight loss and exercise, even of modest degree, increase insulin sensitivity and often improve glucose control in diabetes.

21. Reproductive Disorders Male hypogonadism is associated with increased adipose tissue. In men whose weight is >160% ideal body weight (IBW), plasma testosterone and sex hormone–binding globulin (SHBG) are often reduced, and estrogen levels are increased. Most obese women with oligomenorrhea have polycystic ovarian syndrome (PCOS), with its associated anovulation and ovarian hyperandrogenism ; 40% of women with PCOS are obese.

22. Cardiovascular Disease The Framingham Study revealed that obesity was an independent risk factor for the 26-year incidence of cardiovascular disease in men and women. When the additional effects of hypertension and glucose intolerance associated with obesity are included, the adverse impact of obesity is even more evident. Obesity is also associated with hypertension. The effect of obesity on cardiovascular mortality in women may be seen at BMIs as low as 25.

23. Pulmonary Disease Obesity may be associated with a number of pulmonary abnormalities. These include reduced chest wall compliance, increased work of breathing, increased minute ventilation due to increased metabolic rate, and decreased functional residual capacity and expiratory reserve volume. Severe obesity may be associated with obstructive sleep apnea and the “obesity hypoventilation syndrome”.

24. Hepatobiliary Disease Obesity is frequently associated with nonalcoholic fatty liver disease (NAFLD). The hepatic fatty infiltration of NAFLD progresses in a subset to inflammatory nonalcoholic steatohepatitis (NASH) and more rarely to cirrhosis and hepatocellular carcinoma. Obesity is associated with enhanced biliary secretion of cholesterol, supersaturation of bile, and a higher incidence of gallstones.

25. Cancer Obesity is associated with increased risk of several cancer types, and in addition can lead to poorer treatment outcomes and increased cancer mortality. Obesity in males is associated with higher mortality from cancer of the esophagus , colon, rectum, pancreas, liver, and prostate. Obesity in females is associated with higher mortality from cancer of the gallbladder, bile ducts, breasts, endometrium, cervix, and ovaries.

26. Bone, Joint, and Cutaneous Disease Obesity is associated with an increased risk of osteoarthritis. Potentially linked as well to activation of inflammatory pathways that could promote synovial pathology. The prevalence of gout may also be increased. One of the skin problems associated with obesity is acanthosis nigricans , manifested by darkening and thickening of the skinfolds on the neck, elbows, and dorsal interphalangeal spaces.

27. EVALUATION AND MANAGEMENT OF OBESITY Children and adolescents also are becoming more obese, indicating that the current trends will accelerate over time. Obesity is associated with an increased risk of multiple health problems, including hypertension, type 2 diabetes, dyslipidemia , obstructive sleep apnea , nonalcoholic fatty liver disease, degenerative joint disease, and some malignancies. EVALUATION Physicians should screen all adult patients for obesity and offer intensive counseling and behavioral interventions to promote sus- tained weight loss.

28. The five main steps in the evaluation of obesity, as described below, are A focused obesity-related history. A physical examination to determine the degree and type of obesity. Assessment of comorbid conditions. Determination of fitness level, and Assessment of the patient’s readiness to adopt lifestyle changes.

29. Body Mass Index (BMI) and Waist Circumference Three key anthropometric measurements are important in evaluating the degree of obesity: weight , height , and waist circumference.

30. Physical Fitness Several prospective studies have demonstrated that physical fitness, measured by a maximal treadmill exercise test, is an important predictor of all-cause mortality rate independent of BMI and body composition. Obesity-Associated Comorbid Conditions The evaluation of comorbid conditions should be based on presentation of symptoms, risk factors, and index of suspicion. For all patients, a fasting lipid panel should be performed.

31. Identifying the High-Risk Patient Efforts are under way to develop more practical and useful assessments to identify patients who are at high risk in addition to using BMI alone. American College of Endocrinology (ACE) have proposed an obesity disease staging system: These staging is based on ethnic-specific BMI cutoffs in conjunction with assessment for adiposity-related complications.

32. Staging includes: Stage 0 is assigned to individuals who are overweight or obese by BMI classification but have no complications. Stages 1 and 2 are defined as individuals who are overweight or obese by BMI classification and have one or more mild-moderate complications ( stage 1 ) or at least one severe complication ( stage 2 ). Edmonton Obesity Staging System ( EOSS ), classifies individuals with obesity into five graded categories (0–4), based on their morbidity and health-risk profile along three domains— medical , functional , and mental .

33. Assessing the Patient’s Readiness to Change An attempt to initiate lifestyle changes when the patient is not ready usually leads to frustration and may hamper future weight-loss efforts. Readiness can be viewed as the balance of two opposing forces : Motivation, or the patient’s desire to change; and Resistance, or the patient’s resistance to change.

34. TREATMENT FOR OBESITY THE GOAL OF THERAPY The primary goals of treatment are to improve obesity-related comorbid conditions and reduce the risk of developing future comorbidities. Information obtained from the history, physical examination, and diagnostic tests is used to determine risk and develop a treatment plan. Not all patients who are deemed obese by BMI alone need to be treated, as exemplified by the concepts of obesity paradox or the metabolically healthy obese.

35. TREATMENT ALGORITHM

36. LIFESTYLE MANAGEMENT Obesity care involves attention to three essential elements of lifestyle: dietary habits, physical activity, and behavior modification . Obesity is fundamentally a disease of energy imbalance. Lifestyle management has been shown to result in a modest (typically 3–5 kg) weight loss when compared with no treatment or usual care.

37. Diet Therapy The primary focus of diet therapy is to reduce overall calorie consumption. Guidelines from the American Heart Association/American College of Cardiology/The Obesity Society (AHA/ACC/TOS) : Recommend initiating treatment with a calorie deficit of 500–750 kcal/d compared with the patient’s habitual diet. A diet of 1200–1500 kcal/d for women and 1500–1800 kcal/d for men Can be prescribed.

38. It is important that dietary counseling remains patient centered and that the selected goals are SMART (specific, measurable, agreed upon, realistic, timely). Maintaining a diet rich in whole grains, fruits, vegetables, and dietary fiber ; decreasing sodium intake to <2300 mg/d; consuming fat-free or low-fat dairy products; and keeping added sugars and saturated fat intake to <10% of daily calories can be applied for treatment of obese. Use of meal replacements in the diet has been shown to result in a 7–8% weight loss.

39. Another dietary approach to consider is based on the concept of energy density. It refers to the number of calories (i.e., amount of energy) a food contains per unit of weight. Adding water or fiber to a food decreases its energy density by increasing weight without affecting caloric content. Dry foods and high-fat foods such as pretzels, cheese, egg yolks, potato chips, and red meat have a high-energy density. Diets containing low-energy-dense foods have been shown to control hunger and thus to result in decreased caloric intake and weight loss.

40. Occasionally, very low-calorie diets (VLCDs) are prescribed as a form of aggressive dietary therapy. The primary purpose of a VLCD is to promote a rapid and significant (13- to 23-kg) short-term weight loss over a 3- to 6-month period. Medical supervision is required because of the rapid rate of weight loss and potential for health complications.

41. Physical Activity Therapy Although exercise alone is only moderately effective for weight loss, the combination of dietary modification and exercise is the most effective behavioral approach for the treatment of obesity. Physical Activity Guidelines for Americans : Recommend that adults should engage in 150 min of moderate-intensity or 75 min a week of vigorous-intensity aerobic physical activity per week, performed in episodes of at least 10 min and preferably spread throughout the week.

42. Asking the patient to wear a pedometer or accelerometer to monitor total accumulation of steps or kcal expended as part of the activities of daily living is a useful strategy. A high level of physical activity (>300 min of moderate-intensity activity per week) is often needed to lose weight and sustain weight loss. Consultation with an exercise physiologist or personal trainer may be helpful.

43. Behavioral Therapy Cognitive behavioral therapy is used to help change and reinforce new dietary and physical activity behaviors . Strategies include self-monitoring techniques ,stress management,stimulus control , social support; problem solving; and cognitive restructuring to help patients develop more positive and realistic thoughts about themselves. These techniques are time consuming to implement, their supervision is often undertaken by ancillary office staff, such as a nurse-clinician or registered dietitian.

44. PHARMACOTHERAPY Adjuvant pharmacologic treatments should be considered for patients who have concomitant obesity-related diseases and for whom dietary and physical activity therapy has not been successful. When an antiobesity medication is prescribed, patients should be actively engaged in a lifestyle program such support increases total weight loss. Medications for obesity have traditionally fallen into two major categories: 1) appetite suppressants ( anorexiants ) & 2 )gastrointestinal fat blockers..

45. Centrally Acting Anorexiant Medications Anorexiants affect satiety (the absence of hunger after eating) and hunger (the biologic sensation that prompts eating). The biologic effect of these agents on appetite regulation is produced by augmentation of the neurotransmission of three monoamines: norepinephrine; serotonin (5-hydroxytryptamine [5-HT]) and to lesser extent dopamine. Lorcaserin is a selective 5-HT2C receptor agonist with a functional selectivity.

46. Lorcaserin has undergone two randomized, placebo-controlled, double-blind trials for efficacy and safety. Naltrexone SR/bupropion SR (NB) is a combination of an opioid antagonist and a mild reuptake inhibitor of dopamine and norepinephrine, respectively. Naltrexone is approved by the FDA for the treatment of alcohol dependence and for the blockade of the effects of exogenously administered opioids, whereas bupropion is approved as an antidepressant and smoking cessation aid.

47. Peripherally Acting Medications Orlistat is a synthetic hydrogenated derivative of a naturally occurring lipase inhibitor, lipostatin , that is produced by the mold Streptomyces toxytricini . This drug is a potent, slowly reversible inhibitor of pancreatic, gastric, and carboxylester lipases and phospholipase A2. Orlistat required for the hydrolysis of dietary fat into fatty acids . Orlistat produces a weight loss of ~9–10%, whereas placebo recipients have a 4–6% weight loss.

48. SURGERY Bariatric surgery can be considered for patients with severe obesity (BMI, ≥40 kg/m2) or for those with moderate obesity (BMI, ≥35 kg/m2) associated with a serious medical condition. Weight-loss surgeries have traditionally been classified into three categories on the basis of anatomic changes: restrictive , restrictive malabsorptive , and malabsorptive . Restrictive surgeries limit the amount of food the stomach can hold and slow the rate of gastric emptying. Laparoscopic adjustable gastric banding is the prototype of this category.

49. Metabolic effects resulting from bypassing the foregut include altered responses of ghrelin, glucagon-like peptide 1, peptide YY3-36, and oxyntomodulin . The mean percentage of total body weight lost at 5 years is estimated at 20–25%. In the laparoscopic sleeve gastrectomy, the stomach is restricted by stapling and dividing it vertically, removing ~80% of the greater curvature and leaving a slim banana-shaped remnant stomach along the lesser curvature.

50. BARIATRIC SURGICAL PROCEDURES

51. Roux- en -Y is the most commonly undertaken and most accepted bypass procedure. These procedures generally produce a 30–35% average total body weight loss that is maintained in ~60% of patients at 5 years. The prevention and treatment of type 2 diabetes resulting from bariatric surgery has garnered the most attention. Several randomized controlled studies have shown greater weight loss and more improved glycemic control at 1 and 3 years among surgical patients than among patients receiving conventional medical therapy.