1. ThiQar college of Medicine Family & Community medicine dept
ThiQar college of Medicine Family & Community medicine dept. Nutrition L 6, 3rd stage by: Dr. Muslim N. Saeed Thursday, April 20th ,2017

2. Obesity *Overview *Assessment *Demographics *Determinants of Obesity
*Medical Complications

3. Overview
• Body mass index (BMI) determines the classification of obesity for clinical use. • Waist circumference reflects the distribution of adipose tissue and helps determine obesity risk. WC should be less than 101 cm in male, and less than 88 cm in female.

4. Assessment
The primary parameter used to categorize weight is BMI: BMI= body Wt.(Kg)\ squared Ht. in meters Ex. Wt= 70 , Ht=180 cm. BMI= 70\ (1.8*1.8) =70 \ 3.24=21.60 kg\m and 24.9 is normal in adults -25 to 29.9 is overweight -30 to 34.9 is class I obesity, 35 to 39.9 is class II obesity. Class III, “severe,” or “extreme” obesity is 40 and higher. Calculated from height and weight and expressed in kg/m2.

5. BMI is a recommended parameter to assess obesity, but an imperfect tool to measure adiposity. A high value may reflect greater lean body mass rather than adiposity in muscular individuals. In addition, BMI does not reflect distribution of body fat, a factor that influences risk.

6. Body fat percentage is a more precise assessment of adiposity
Body fat percentage is a more precise assessment of adiposity. The techniques of skin fold measurements and bioelectric impedance assays can be used, Cutoff levels for body fat percentage selected by WHO are used to stratify health risks associated with overweight and obesity.

7. From birth to age 2 years, overweight is assessed by the weight-for-length percentile; at or above the 95th percentile is considered overweight or obese. For the pediatric population age 2 to 19 years, percentile ranks based on CDC growth charts to define overweight and obesity.

8. The CDC defines overweight between ages 2 and 19 years as a BMI between the 85th and 95th percentiles for age and sex. A child or adolescent with BMI at or above the 95th percentile is considered obese.

9. Central obesity, also referred to as visceral, abdominal, or android obesity, is associated with a greater risk of complications, including the metabolic syndrome. gender- specific waist circumference, taken at the level of the iliac crest, has proved to be a better assessment of the distribution of body fat.

10. Health risks increase above a waist circumference of 35 inches (88 cm) in women and 40 inches (101 cm) in men.

12. Demographics
• Men are more likely than women to have central obesity. • Obesity is inversely related to education and socioeconomic status. • Obesity is more prevalent in rural than urban areas.

13. 1- Gender Differences: Men are more likely than women to be overweight, whereas women are more likely to be obese. Men, however, are more likely to have central obesity, associated with greater health risks.

14. 2- Race and Ethnic Origin: 3- Socioeconomic Status: The prevalence ranges from approximately 2% in the least developed countries to over 30% in the most developed countries. In developed countries, however, lower socio-economic status is associated with an increased risk, because of reduced access to medical care, healthy foods, and exercise facilities among lower socioeconomic groups.

15. 4- Education Level: Education level is inversely related to the risk of obesity, which may partly explain the decreased risk with increased socioeconomic status in developed countries. 5- Rural and Urban Differences: the prevalence of obesity is greater in rural than urban areas. Factors that reduce physical activity may play a role. Reduced availability of healthy food choices is also thought to contribute.

16. 6- Age: The incidence of overweight increases steadily after age 20 until the seventh decade of life. At that point, it levels off and begins a gradual decline. The increased prevalence of overweight is especially alarming in the pediatric population. More than 30% of children and adolescents are overweight or obese.

17. Determinants of Obesity
• Obesity results from the interaction of genetic makeup, environment, and lifestyle. • Genetic factors are estimated to account for 30% to 40% of the variability in adult weight. • Genetic influence is polygenic. • Specific metabolic or endocrine disorders account for less than 1% of the obese population.

18. Genetic Factors
Most of the genetic influence on obesity is poly-genic. More than 250 genes and chromosomal regions are associated with phenotypic obesity. Single-gene mutations related to obesity often involve leptin and melanocortin. There are a number of congenital syndromes in which obesity is part of the phenotype.

19. Modulation of Appetite
Many hormonal factors are involved in appetite, as well as in the absorption, storage, and use of calories. Factors providing input to the brain include leptin levels, vagal afferent activity, and fluctuation in plasma glucose levels. Neuropeptides and monoamine neuro-transmitters are also involved in appetite control.

20. Lifestyle Influences
• Increased caloric intake is related in part to “portion distortion,” linked to eating away from home.
• Smoking cessation is associated with weight gain of 4 to 5 kg (on average).
• Many antidepressants, neuroleptics, and anticonvulsants are associated with weight gain.
• Decreased overall physical activity (not just “exercise”) is a major factor associated with the increasing prevalence of overweight and obesity.

21. obesity develops when caloric intake exceeds caloric expenditure against a background of genetic influences. The chief determinants of energy imbalance are lifestyle factors. Individual total energy requirements depend on the basal metabolic rate (BMR), thermic effect of food, and energy needed for the day’s physical activities.

22. The chief determinant of BMR is the amount of lean body mass, which can be difficult to increase. Physical activity (exercise and activity through -out the day) is the most variable component of energy expenditure. The major reasons for weight gain are therefore excessive calorie intake and decreased overall physical activity.

23. Caloric Intake: -tendency to consume more calories needed
Caloric Intake: -tendency to consume more calories needed. -Some of this increase is related to increased portion size. -Energy density also plays a role. -The frequency of meals may play a small role. Eating smaller meals more frequently is associated with less overweight. -Large meals are associated with more insulin release.

24. Activity Changes Decreased energy expenditure may play a greater role in the development of obesity than increased caloric intake. most of the decrease in physical activity energy expenditure has occurred in daily physical activities, not exercise.

25. Smoking Cessation: Often cited by smokers as a reason to continue smoking, stopping cigarette smoking does lead to weight gain. The average weight gain is 4 to 5 kg over months Typically, the person gains 1 to 2 kg in the first few weeks after cessation.

26. Medications A number of medications are associated with weight gain, including antidepressants, antipsychotics, anticonvulsants, and hypoglycemic agents. Tricyclic antidepressants, monoamine oxidase inhibitors are the anti-depressants most likely to cause weight gain. -Chronic systemic steroid use can cause a cushinoid type of obesity.

27. -Insulin, as well as oral hypo-glycemics that increase production or release of insulin, promote weight gain. -It should be noted that metformin, which increases insulin sensitivity, is associated with modest weight loss and may ameliorate the weight gain from other hypo-glycemics.

28. Endocrine and Metabolic Factors
Specific identifiable endocrine or metabolic disorders known to cause obesity account for less than 1% of the obese population, contrary to what is commonly believed.

29. Hypothyroidism -in children, associated with slow statural growth and developmental delay. -More common among adults and more often seen in women, hypothyroidism is a relatively rare cause of obesity.

30. Neuroendocrine Factors The rarely seen neuroendocrine causes for obesity result from injury to the ventromedial hypothalamus, due to tumor, trauma, or surgery to the posterior fossa.

31. Cushing’s Syndrome This endocrine disorder is associated with central obesity and “buffalo hump” along with axillary striae, glucose intolerance and hypertension.

32. Polycystic Ovary Syndrome More than 50% of women affected by this relatively common disorder are obese. Insulin resistance is a consistent finding, even in the absence of obesity.

33. Growth Hormone Deficiency Although growth in height is impaired in growth hormone deficiency, there is also an increase in truncal obesity.

34. Medical Complications of obesity
• Obesity is more closely related to elevated triglycerides and low HDL cholesterol than elevated total and LDL cholesterol. • Weight loss is the most effective lifestyle change to lower blood pressure. • Up to 80% of cases of type 2 diabetes mellitus are attributable to overweight and obesity. • Obesity plays a role in 14% of cancer deaths in men and 20% in women.

35. Hypertension
The obesity-related increase in blood pressure (BP) is associated with an increase in vascular resistance as well as sodium resorption. Controlling overweight would reduce the incidence of hypertension by an estimated 28% - 48%. Weight loss is the most effective lifestyle change to decrease blood pressure.

36. Dyslipidemia
Obesity is associated with elevated TG levels, reduced (HDL-C), and an increase in the more atherogenic, small, dense LDL particles. This weight loss is generally accompanied by a decrease in total cholesterol and LDL-C.

37. Type 2 Diabetes Mellitus
The risk of T2DM is lowest below a BMI of 22 to 23 kg/m2. At a BMI of 31, the risk for women is 40-fold greater than in women with a BMI less than 22. For men, the risk of Type 2 DM above a BMI of 35 kg/m2 was increased 60-fold. Up to 80% of cases of T2DM can be attributed to overweight and obesity.

38. As weight increases, insulin resistance and compensatory insulin secretion also increase. At some point, the body’s ability to secrete insulin does not meet requirements, and blood glucose rises. Weight loss is recommended to lower elevated glucose levels in overweight and obese persons with T2DM.

39. Metabolic Syndrome
The metabolic syndrome brings together a number of the comorbidities associated with obesity. Definition: BP elevation of at least 130/85 mm Hg, (2) serum TG level higher than 150 mg/dL, (3) HDL-C level less than 50 mg/dL in women and 40 mg/dL in men, (4) fasting blood glucose level at least 110 mg%, (5) waist circumference more than 35 inches in women and 40 inches in men. -WHO add increased urinary albumin excretion and require the presence of impaired glucose tolerance or T2DM.

40. Heart Disease
The presence of obesity in the absence of other risk factors may lead to cardiomyopathy and congestive heart failure (CHF) as the workload of the heart increases. For women with BMI more than 29 kg/m2, CAD risk increases 3.3-fold compared with women with BMI less than 21 kg/m2.

41. Cancer
Obesity may be the largest avoidable cause of cancer for non smokers. Cancers of the esophagus, colon, kidney, gallbladder, and pancreas, as well as multiple myeloma and non-Hodgkin’s lymphoma. Also, increased risk of prostate, gastric, ovarian, and endometrial cancers.

42. Obstructive Sleep Apnea
Excessive weight is a major risk factor. About 70% of OSA patients are obese.

43. Pulmonary Disease
Obesity can have an impact on overall lung function, It increases the work of breathing. Obesity increases pressure on the diaphragm, reducing lung function. Asthma is exacerbated with increased weight, and obesity-hypoventilation syndrome and cor pulmonale is associated with marked degrees of obesity.

44. Fatty Liver Disease
Fatty liver disease is the most common reason for elevated serum liver enzymes. First described in obese diabetic females, fatty liver disease is widely recognized as a complication of obesity.

45. Orthopedic Disorders
Overweight children have an increased risk of slipped femoral capital epiphysis, genu valga, pes planus, and scoliosis. In adults, degenerative joint disease, particularly of the knee, is related in part to mechanical factors resulting in increased compressive forces on the knee.

46. Gallbladder Disease
Obesity, hyper-insulinemia and the metabolic syndrome, are risk factors for gallbladder disease, because cholesterol production increases with weight gain, and cholesterol is excreted into bile. The increased cholesterol relative to bile acids can lead to the formation of stones.

47. Psychological Impact
Self-awareness of overweight and the associated psychological impact can be seen in children as young as 5 years old and can result in poor self-esteem. This may result in poor body image, especially in young women. Eating disorders, can complicate the management of obesity. In adults, obesity is associated with depression in women.

48. End