Obesity in Adolescents

1. Obesity in Adolescents Gilberto A. Velez-Domenech, M.D. New York Medical College Department of Pediatrics Division of Adolescent Medicine

2. Outline • Definitions • Epidemiology • Etiology and Influencing Factors • Puberty • Influence and Effects on Health • Prevention • Therapy • Resources

3. Overweight and Obesity • Body weight above an arbitrary standard • Excess body fat • Often defined in relation to height

4. Body Mass Index (BMI) • BMI=Wt(Kg)/Ht(m)2 • Expert Committee on Clinical Guidelines for Overweight in Adolescent Preventive Services (Himes and Dietz, 1994) • Correlation of 0.7 to 0.8 with body fat content

5. Children and Adolescents • At risk for Overweight = BMI above the 85th and up to the 95th percentile for age • Overweight = BMI above the 95th percentile for age Young Adults and Adults • BMI > 25 kg/m2

6. Charts Standard CDC Charts

7. Summary • Methods that use just height and weight are cheap and easy to use but do not reflect regional body fat distribution. • Skin fold measurements are susceptible to inter-observer error. • Highly technical methods are precise but expensive and limited to research settings

8. Epidemiology • 60 to 70% of obese adolescents are female • 80 to 85% of obese adolescents will become obese adults. • If a child is obese at age 12 the odds are 4:1 against attaining IBW as adults • If a child is obese after adolescence the odds are 28:1 against attaining IBW as adults

9. Epidemiology • Serdula, 1995. National Study: 44% of female students and 15% of male students were trying to loose weight. • Exercise: 51% female / 30% of male • Skipping Meals: 49% female / 18% male • Diet Pills: 4% female / 2% male • Vomiting: 3% female / 1% male

10. National Health and Nutrition Examination Survey (NHANES)

11. Trends in Overweight for Children by Age Group

12. Trends in Overweight for Male Children by Age Group

13. Trends in Overweight for Female Children by Age Group

14. Overweight Children by Age and Race/Ethnicity: NHANES 1999-2000

15. Overweight Male Children by Age & Race/Ethnicity: NHANES 1999-2000

16. Overweight Female Children by Age & Race/Ethnicity: NHANES 1999-2000

17. Etiology & Influencing Factors • Cause still unclear • 5% of Obese Children and Adolescents have an underlying specific cause • 3% = Endocrine • Hypothyroidism • Cushing Syndrome • Hypogonadism • 2% Rare Syndromes (Prader-Willi et. al.)

18. Familial or Genetic • Swedish Twin Studies • 1 Parent Obese = 30% Risk • 2 Parents Obese = 70% Risk • Stunkard (1986) • BMI correlation between adoptees and biological parents • No correlation with adoptive parents • Stunkard (1990) • High correlation BMI between twins

19. Fat Cell Theory • Fat cells gained early in life and during puberty cannot be lost, only reduced in size. • Overfeeding early in first year of life and during puberty increases the number of fat cells • Adolescents who have propensity to obesity have increased number of fat cells

20. Activity and Energy Expenditure • Dietz (1993) stated that the most powerful predictor of the development of obesity in adolescence was the time that a child 6 to 11 years of age spends viewing television, even after controlling for other variables.

21. Behavior • Eating Fast • Skipping breakfast and/or lunch and eating the majority of calories at night. • Eating when not hungry but when food is available • Eating when appetite is stimulated by environmental cues • Eating when depressed or anxious • Eating in association with other activities • Overindulging in “Fast Foods”

22. Central Regulation Theory • The hunger or satiety center in the hypothalamus may not function properly in suppressing appetite.

23. Psychological Theory • Obese individuals are depressed or anxious and use eating as a means to alter their mood.

24. Body Image Theory • Obese adolescents have a distorted fat body image. • One cannot achieve weight change until one has visualized a smaller body image and become comfortable with it.

25. Hormonal Theory • Leptin • Encoded by the obese gene • Produced by the adipose tissue • Signal satiety and alter eating behavior • Monitors and controls body fat and energy balance

26. Pubertal Changes: Effects of Puberty on Body Composition • Lean Body Mass increases in Both Sexes • More in Male than in Females because of the greater increase in skeletal muscle mass under the effect of testosterone. • Maximum increase in muscle mass occurs at the time of PHV in both sexes • Maximum fat deposition occurs 2 years before PHV and in females it continues throughout puberty • Ultimately female adults have more body fat than males

27. Pubertal Changes: Effects of Obesity on Puberty • Taller and larger in skeletal mass and more advanced in skeletal development. • Earlier sexual maturation and menarche. • Higher levels of hemoglobin/hematocrit. • Menstrual Irregularities

28. Influence and Effects on Health Psychosocial Consequences • Poor Body Image • Social Isolation for fear of rejection and non-acceptance by peers • Gortmaker, 1993. 7-year Study of 16-24 y/o • Obese ♀ completed fewer years of school • Less likely to be married • Lower household incomes • Higher rates of poverty • Low self-esteem • Depression

29. Influence and Effects on Health General Morbidity and Mortality • Obese adolescents who become obese adults will have more severe obesity than those adults whose obesity began in adulthood. • Greater morbidity and mortality due to cardiovascular disease • Effect of adolescent obesity on adult morbidity and mortality is independent of the effect of adolescent obesity on adult weight.

30. Influence and Effects on Health • Hypertension • Cerebrovascular Disease • Cardiovascular Disease • Serum Lipids • Diabetes Mellitus (Type 2) • Polycystic Ovary Syndrome • Cancer • Skeletal Deformity and Arthritis

31. Prevention • During Pregnancy • Moderate weight gain during 3rd trimester • During Infancy and Childhood • Breast feed in first year of life • Delay cereals until 3 to 4 months of age • Be sensitive to the deceleration of growth at 18 months of age

32. Prevention • During Puberty and Adolescence • Encourage healthy nutritional practices in early puberty (Remember the fat cells) • Encourage lifestyle of activity and participation through role modeling • Discourage TV, DVD and videotape watching and video game use.

33. Prevention Reducing television, videotape, DVD and video game use may be the most promising population based approach to prevention of childhood obesity.

34. Treatment: General Aspects • HUGE CHALLENGE!!! • Determine who is at greater risk • In the absence of complications obesity is clinically significant when Wt is over 20 – 30% IBW for height and age. • If complications are present it is always clinically significant. • Focus on control, not cure • Ascertain motivation.

35. Treatment: Critical Areas • Motivation • Supportive Social and Family Framework • Willingness to increase physical activity • Realistic Goals

36. Diet: General Principles • Deficit of 500 kcal/day = 1 lb wt loss/week • Food types • Eating habits (Patient and Family) • Situation-dependent eating • Family and cultural preferences • Good nutritional balance among food groups.

37. Diets: General Principles • Energy Needs • Males = [900 + (10 x W0] x Activity Factor • Females = [800 + (7 x W)] x Activity Factor • Activity Factor • Low Activity = 1.2 • Moderate Activity = 1.4 • High Activity = 1.6 • Energy required to maintain each Kg of body weight = 22 Kcal

38. Diets • Ketogenic • Very-low-calorie (< 400 Kcal/day) • Glycemic Index • Prolonged fasting • Special food combinations (Steak and Grapefruit Diet) • Balanced Low-calorie (~1200 Kcal/day)

39. Balanced Diet • Foods from five groups: dairy, meat, bread, fruits and vegetables • Three meals per day • Eat less food or calories than previously • Instructions for food preparation • Instructions for food substitution (L vs H) • Instructions for food shopping

40. Physical Activity • Walking instead of riding the car or bus • Stairs instead of elevators • Not using the channel flipper • Exercise prescription: Over 30 min per day / 4 days per week of anything acceptable

41. Cognitive Behavioral Therapy • Contract and reward system • Initial food diary • Time spent eating • Place • Hunger rating • Mood • Associated activity • Food consumed • Amount

42. Cognitive Behavioral Therapy • Behavior Change • Eat three regular meals • Eat favorite dish first • For a particular food eat favorite part first • Eat defensively: Avoid “junk food” • Eat slowly, chew – swallow – reload • Do not keep “weakness food” • Eat where eating is meant to occur

43. Cognitive Behavioral Therapy • Behavior Change (Cont.) • Do not watch TV while eating • Do not eat on the go • Learn difference between Appetite & Hunger • Eat when hungry, not when food is available • Have a breakout activity when depressed, anxious or unhappy • Be honest about lapses in control

44. Groups • Encouragement and support • Release of feelings • Peer contact and acceptance • Non-commercial • TOPS • Overeaters Anonymous • Commercial • Weight Watchers • Diet Workshop • Jenny Craig • Richard Simmons Slimmons

45. Other • Anorexigenic drugs • Bariatric surgery

46. Resources • Books • The Hilton Head Diet for Children and Teenagers: The Safe and Effective Program That Helps Your Child Overcome Weight Problems for Good, by Peter M. Miller (Warner Books, Inc., 1993) • Girl Power in the Mirror: A Book about Girls, Their Bodies and Themselves, by H. Cordes (Lerner Publishing Group, 1999) • Safe Dieting for Teens, by Linda Ojeda and Lisa Lee (Hunter House, Inc., 1992)

47. Resources • Web Sites • http://www.niddk.nih.gov/health/nutrit/pubs/choose.htm. Choosing a safe weight reduction program from NIH • http://www.health.gov/dietaryguidelines/. Dietary Guidelines • http://www.niddk.nih.gov/health/nutrit/pubs/presmeds.htm. Prescription medications for obesity • http://www.niddk.nih.gov/health/nutrit/win.htm. Weight-control Information Network