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  1. 1. Obesity: Pathophysiology, And Risk Assessment2/13/2012 1
  2. 2. • Obesity:• Excessive amount of body fat. – Women with > 35% body fat. – Men with > 25% body fat.• Increased risk for health problems.• Are usually overweight, but can have healthy Body Mass Index(BMI) and high % fat.• BMI =weight kilograms / height meters22/13/2012 2
  3. 3. • Desirable % Body Fat:• Men: 8-25%.• Women 20-35%.2/13/2012 3
  4. 4. • Regional Distribution:• The regional distribution of body fat affects risk factors for the heart disease and type 2 diabetes.2/13/2012 4
  5. 5. • Body Fat Distribution: Gynoid• Lower-body obesity--Pear shape.• Encouraged by estrogen and progesterone.• Less health risk than upper-body obesity.• After menopause, upper-body obesity appears.2/13/2012 5
  6. 6. • Body Fat Distribution: Android• Upper-body obesity--apple shape.• Associated with more heart disease, Hypertensiion(HTN), Type II Diabetes.• Abdominal fat is released right into the liver.• Encouraged by testosterone and excessive alcohol intake.• Defined as waist measurement of > 40” for men and >35” for women.2/13/2012 6
  7. 7. • Body Fat Distribution:2/13/2012 7
  8. 8. • Weight Management:• Balancing energy intake and energy expenditure is the basis of weight management throughout life.• Dieting and physical exercise.• Orlistat (Xenical) medication to treat obesity.• In severe cases, bariatric surgery is performed or an intragastric balloon is placed to reduce stomach volume.2/13/2012 8
  9. 9. Pathophysiology2/13/2012 9
  10. 10. • Role of Brain Neurotransmitters:• Neurotransmitters govern the body’s response to starvation and dietary intake.• Decreases in serotonin and increases in neuropeptide Y are associated with an increase in carbohydrate appetite.• Neuropeptide Y increases during deprivation; may account for increase in appetite after dieting.2/13/2012 10
  11. 11. • Hormonal Regulation of Body Weight:• Norepinephrine and dopamine—released by sympathetic nervous system in response to dietary intake.• Fasting and semistarvation lead to decreased levels of these neurotransmitters—more epinephrine is made and substrate is mobilized.2/13/2012 11
  12. 12. • Hormones And Weight:• Leptin is produced by adipose tissue to signal fat storage reserves in the body, and mediates long-term appetitive controls (i.e. to eat more when fat storages are low and less when fat storages are high).• Ghrelin produced by the stomach modulating short-term appetitive control (i.e. to eat when the stomach is empty and to stop when the stomach is stretched)2/13/2012 12
  13. 13. 2/13/2012 13
  14. 14. • Hunger vs. Satiety:• Satiety—postprandial state when excess food is being stored.• Hunger—postabsorptive state when stores are being mobilized.2/13/2012 14
  15. 15. • Hunger vs. Satiety—contd:• Feedback mechanism with signal from adipose mass when weight loss occurs—eating is the natural result.• Not always identified in the elderly.• This occurs mostly in young people.2/13/2012 15
  16. 16. • Causes of Obesity:2/13/2012 16
  17. 17. • Causes of Excessive Energy Intake:• Active: large portion sizes, frequent meals and snacks.• Passive: excessive intake of energy-dense foods containing hidden calories.• Variety of options: the greater the variety of foods offered, the greater the intake.2/13/2012 17
  18. 18. • Low Energy Expenditure:• Sedentary lifestyle.2/13/2012 18
  19. 19. • Genetics:• Identical twins have similar weights.• Genes affect metabolic rate, fuel use, brain chemistry, body shape.• The thrifty gene hypothesis postulates that due to dietary scarcity during human evolution people are prone to obesity.• Thrifty metabolism gene allows for more fat storage to protect against famine.2/13/2012 19
  20. 20. Genetics:Obesity tends to run in families.• If both parents are normal weight – 10% chance of obesity in offspring.• If one parent is obese – 40% chance.• If both parents obese – 80% chance.2/13/2012 20
  21. 21. • Environmental factors influence weight:• Overeating learned early in childhood.• Urging children to eat more, clean their plates.• Use of food as a reward.2/13/2012 21
  22. 22. • Medical and psychiatric illness:• Physical and mental illnesses and the pharmaceutical substances.• Hypothyroidism, Cushing’s syndrome, growth hormone deficiency, and the eating disorders: Binge eating disorder and Night eating syndrome.• Insulin, sulfonylureas, thiazolidinediones, atypical antipsychotics, antidepressants, steroids, certain anticonvulsants (phenytoin and valproate), and some hormonal contraception.2/13/2012 22
  23. 23. • Obesity is a Growing Problem:• 127 million adults in the U.S. are overweight, 60 million obese, and 9 million severely obese.• 66 percent of U.S. adults are overweight (BMI≥25).• 32 percent are obese (BMI≥30).• 17% of children and adolescents ages 2-19 are overweight.2/13/2012 23
  24. 24. • Obesity: A Major Health Issue:• Obesity is the SECOND preventable cause of death and disability (smoking is #1).• Obesity is associated with increased risk of heart disease, stroke, gallbladder disease, cancer, osteoarthritis, sleep apnea.• Obesity-related health problems cost $75 billion annually (2003 data).• The public pays about $39 billion a year -- or about $175 per person -- for obesity through Medicare and Medicaid programs.2/13/2012 24
  25. 25. • Health Problems Associated with Excess Body Fat: • Type 2 diabetes • Surgical risk • Gallstones • Lung (pulmonary) disease • Cancers (breast, colon, pa • Sleep apnea ncreas, gallbladde • HTN r) • CVD • Infertility • Bone and joint • Pregnancy- disorders (gout, osteoarthrit difficult delivery is)2/13/2012 • Reduced agility 25
  26. 26. • Metabolic Syndrome Criteria*:Three or more of the following abnormalities:• Waist circumference >102 cm (40 inches) in men and > 88 cm (35 inches) in women.• Serum triglycerides of at least 150 mg/dL.• High density lipoprotein level <40 mg/dL in men and <50 mg/dl in women.• Blood pressure >=135/85 mm hg.• Serum glucose >=110 mg/dl. –*Adult Treatment Panel (ATP) III Guidelines. National Cholesterol Education Program, 2001.2/13/2012 26
  27. 27. • Polycystic Ovary Syndrome (PCOS):• Endocrine disorder characterized by hyperandrogenism and insulin resistance.• Associated with android obesity.• Affects 5-10% of reproductive age women.• Erratic menstrual periods, chronic anovulations resulting in multiple ovarian cysts; infertility, acne, hirsutism and alopecia.• Increased risk of heart disease, type 2 diabetes, reproductive cancers.2/13/2012 27
  28. 28. • Management of PCOS:• Symptom oriented, as etiology is unclear.• Individualized diet and exercise plan to promote weight loss and normalize insulin levels.• Medications to alleviate symptoms.2/13/2012 28
  29. 29. • BMI and Health: Below 18.5 Underweight 18.5 – 24.9 Normal 25.0 – 29.9 Overweight Monitor for risk 30.0 and Above Obese Increased health risk 40.0 and above Severely obese Major health risk2/13/2012 29
  30. 30. • REFERENCE:• Internet: http://medicalppt.blogspot.com• en.wikipedia.org2/13/2012 30