Obesity

1. Obesity Welcome to the obesity module. The rapid rise in the prevalence of obesity in both rich and poor countries in recent years has been described as an epidemic.At the global level, excess body weight is the sixth most important risk factor for ill health. Many adverse health outcomes are strongly associated with obesity. For more information about the authors and reviewers of this module, click here

2. We suggest that start with the learning objectives and try to keep these in mind as you go through the module slide by slide, in order. Print-out the mark sheet. As you go along, write your answers to the questions on the mark sheet as best you can before looking at the answers. Award yourself marks as detailed on the mark sheet: one mark for each keyword (shown in red text) in the short answer questions and for every correct answer in the True/False questions. Introduction 2 How should I study this module? • Repeat the module until you have achieved a mark of >80%. • Finish with the formative multiple choice questionnaire to assess how well you have covered the material as a whole. • You should research any issues that you are unsure about. Look in your textbooks, access the on-line resources indicated at the end of the module and discuss with your peers and teachers. • Finally, enjoy your learning! We hope that this module will be enjoyable to study and complement your learning about obesity from other sources.

3. Learning Outcomes By the end of the module, you should be able to: • Define obesity in terms of body mass index (BMI) • Classify obesity in terms of body fat distribution and BMI values • Describe the burden of obesity on the world population • Discuss the role of lifestyle, genetic predisposition and other causal factors in the pathogenesis of obesity • Describe the association between obesity and type II diabetes, hypertension, cancer and reproductive disorders • Define childhood obesity and understand how it relates to adult obesity • Identify the treatment options available for people with obesity

4. Obesity is defined as the excessive accumulation of body fat. There are a number of ways to measurebody fat: Measurements that are simple, cheap and appropriate for routine use include: waist circumference hip circumference waist-to-hip circumference ratio Indices derived from weight and height, e.g. body mass index skin fold thickness using callipers (e.g. triceps, scapular) Measurements of body fat that are expensive and require special equipment and highly trained personnel include: underwater weighing bioelectrical impedance computerized topography How is obesity measured? Introduction 1

5. Classification of obesity (1) – ‘apples’ and ‘pears’ Obesity can be classified into two groups on the basis of body fat distribution and the waist-to-hip circumference ratio. This simple classification is easily understood by the public and also predicts the risk of obesity-related health problems. • The apple shape: • also called “android”, “abdominal” or “central” obesity • people with high waist-to-hip ratios are "apples", their body fat is distributed mainly on the upper trunk, the chest and abdomen giving the typical ‘apple shape’ • individuals are mostly male • A waist-to-hip ratio >1.0 for men and >0.8 for women indicates an increased riskof cardio-vascular disease and diabetes mellitus • The pear shape: • also called “gynaeoid” or “peripheral” obesity • people with lower waist to hip ratios are "pears“ - their body fat is distributed mainly on the lower trunk, the hips and thighs giving the typical ‘pear shape’. • individuals are mostly female. • associated health risks are minimal if any

6. Classification of obesity (2) –body mass index (BMI) BMI = weight in kilograms = kg/m2 square of height in meters The internationally accepted classification for obesity is the Quetelet's Index, also called the Body Mass Index (BMI) The BMI is a measure of a person’s weight in relationto heightand it is calculated as: weight divided by heightsquared (kg/m2)

7. Note: Although overweight is identified by a BMI of ≥ 25.0 kg/m2, the risks of obesity-associated diseases, such as diabetes, hypertension and dyslipidaemia, increase from a BMI of about 21.0 kg/m2. tion 1 WHO classification of obesity Source: Adapted from WHO 1997

8. oduction 1 A weight and height chart is a useful clinical tool to determine a person’s BMI Source: Weight Control Information Network , NIH

9. Advantages of using BMI to classify obesity: it is low-cost and easy to use for health professionals for assessing individuals it is commonly used to determine desirable body weights and allows people to compare their own weight status to that of the general population it correlates well with the amount of body fat as measured by more complex techniques it predicts dangers associated with obesity; as BMI increases the risk for diseases increases it is a useful screening tool to use at the population level and, because it is universally accepted, BMI reference data is available for many different populations Advantages of BMI

10. Which of these men is at risk of ill health and why? 1.72 metre Ht 1.72 metre 84 Kg Wt 84 Kg 28.4 BMI 28.4 Click to reveal answer Disadvantages of BMI These men have the same height, weight and BMI, but have different percent body fat BMI calculated as follows: BMI = 84 = 84 = 28.4 kg/ m2 (1.72)2 2.96 (a) (b) Although BMI is equally high in both men, in (a) it is due to lean body mass whereas in (b) it is due to body fat. This shows that, used alone, a high BMI is not diagnostic of obesity. BMI also varies with age and sex in those <18 years. These are some of the disadvantages of using BMI to assess health risks.

11. End of Section 1 Well done! You have come to the end of the first section. We suggest that you answer Questions 1 to 3 to assess your learning so far. Please remember to write your answers on the mark sheet before looking at the correct answers!

12. Obesity is the excessive accumulation of body fat Body mass index (BMI) is the most universally accepted index of obesity A woman with a BMI of 46.0 is overweight To calculate the BMI of an individual, we need the weight, height and body fat distribution A man with weight 76 kg and height 1.55 m is obese Question 1: Write “T” or “F” on the answer sheet. When you have completed all 5 questions, click on each box and mark your answer. Click for the correct answer a b c d e

13. Question 2: Complete the missing information on your mark sheet regarding the classification of obesity and the associated health riskAward yourself 1 mark for each right answer Click to Reveal Answers

14. Calculate his BMI How would you classify his BMI ? Is the classification of obesity based on BMI reliable for his man and, if not, why? Question 3: A 25 year old male athlete weighs 87.3kg and has a height of 1.75mWrite your answers on the mark sheet. When you have completed all 3 questions, click on the box and mark your answers. Click to Reveal Answers

15. The global burden of obesity The USA has the highest obesity rate in the world. IN American adults, 50m are obese (BMI >30.0) and 6m have class III obesity (BMI >40.0). Obesity in adolescents has increased from 5% in 1966 -1970 to 14% in 1999. The obesity epidemic that began in the United States during the late 1970s is now occurring the rest of the world. Public health officials are concerned that obesity is reaching epidemic proportions in both adults and children. A high prevalence of obesity now occurs in the more affluent populations of countries that have food security problems and significant rates of under-nutrition. Current data indicate that in the world today: • there are > 1.1 billion overweight adults, and at least 312 million of them are clinically obese • 10% of all children are either overweight or obese, while 17.6 million children under the age of five are estimated to be overweight • The prevalence of obesity has increased by about 10-40% in the majority of European countries in the past 10 years. Britain now has the highest obesityrate in Western Europe: 50% of the UK population are overweight (BMI  25.0 kg/m2) and about 20% are obese (BMI  30.0 kg/m2). • Obesity levels range from 5% in China, Japan, and certain African nations to over 75% in urban Samoa. Even in low prevalence countries like China, rates are almost 20% in some cities.

16. Recent increase in the prevalence of obesity in the USA (1) Partners in Global Health Education Source: U.S. Center for Disease Control

17. Men W. Samoa (urban) 25-69 yrs. Former E. Germany25-65 yrs. • - 80 • - 70 • 60 • - 50 • - 40 • - 30 • - 20 • - 10 • - 0 USA 20-74 yrs. England 16-64 yrs. Brazil 25-64 yrs. Japan 20+ yrs. • 1978 1991 1978 1991 • 1987 1993 1985 1989 1992 1980 1966 1991 1995 1975 1989 • - 80 • - 70 • 60 • - 50 • - 40 • - 30 • - 20 • - 10 • - 0 Women • 1978 1991 • 1987 1993 1975 1989 1980 1966 1991 1995 1985 1989 1992 1978 1991 Obesity in adults on the increase - worldwide Dramatic increases in obesity in recent years is not confined to the USA. These graphs illustrate the rise in obesity in adults in both rich and poorer countries. Prevalence of obesity (%) Prevalence of obesity (%) The growing epidemic of obesity - Source: IOTF

18. Obesity in children living in poorer countries Africa & Middle East: 4 year olds Latin America and Caribbean: 4-10 year olds Source: adapted from IOTF unpublished data

19. Prevalence of overweight in 10-year old children in selected countries Source: adapted from IOTF unpublished data

20. Projected prevalence of obesity in adults by2025 Source: IOTF data

21. The financial burden of obesity: WHO data show that obesity accounts for 5-10% of the total health care budget in several developed countries This is probably a low estimate as not all of the cost of management of obesity and its related problems can be calculated In 2000, the U.S. spent $117 billion on obesity (9% of the national total health budget) The morbidity and mortality burden of obesity: Overall, about 2.5 millions deaths are attributed to overweight/obesity worldwide In the UK, about 30,000 deaths are attributable to obesity. Ten times this figure occurs in the US where obesity is the second greatest preventable cause of death following smoking Nearly 70% of cases of cardiovascular disease are associated with obesity Obesity predisposes to an overall reduction of quality of life and premature death from diet related, chronic non-communicable diseases The burden of obesity – costly, deadly…

22. End of Section 2 Well done! This is the end of the second section. We suggest that you proceed to answer question 4 to assess your learning further. Do remember to write your answers on the mark sheet before looking at the right answer!

23. Question 4: Write “T” or “F” on the answer sheet. When you have completed all 5 questions, click on each box and mark your answer. Click for the correct answer • obesity is a worldwide public health problem • obesity is not a major public health problem in developing nations • the highest rate of obesity is found in the U.S.A • obesity related problems account for less than 5% of healthcare budget in developed countries • obesity leads to premature death from diet related chronic communicable diseases a b c d e

24. The energy value of food can be expressed in calories. Obesity occurs when a person consumes morecalories than his/her body needs. Excess calories are stored as fat and lead to weight increase. For example, consuming 3,500 calories more than the body needs results in a gain of 0.45kg of fat. The factors which affect the balance between calories in and calories out differ from one person to another. Obesity is believed to result from a complex interplay of the following factors (click each factor for details): Genetic factors Socio-economic (lifestyle and diet) Cultural factors Psychological and medical factors Calories in and calories out – the imbalance

25. End of Section 3 Well done! This is the end of the third section. We suggest that you proceed to answer questions 5 and 6 to assess your learning further. Do remember to write your answers on the mark sheet before looking at the right answer!

26. Question 5: Which of the following factors will increase the risk of obesity in anindividual?Write “T” or “F” on the answer sheet, then click on each box to mark your answer. Click for the correct answer • physical inactivity • consumption of fast foods • psychological depression • normal sized parents • hyperthyroidism a b c d e

27. Question 6: Several factors play a role in the pathogenesis of obesity. What risk factors match the following pictures? b)? a)? Click to Reveal Answers c)? d)?

28. Medical associations of obesity Hypertension and type II diabetes coronary artery disease, and stroke, cancers and reproductive abnormalities psychological complications including eating disorders, respiratory and other complications Obesity is a disease. Associations with obesity are protean.Click on each medical association for details Effects of obesity Other effects of obesity • increase burden of disease world wide • increase financial burden on national health budgets • decrease in overall life expectancy • social effects including poor quality of life

29. End of Section 4 Well done! This is the end of the fourth section. Please answer questions 7. Do remember to write your answers on the mark sheet before looking at the right answer!

30. Question 7: Which of the following are recognised associations of obesity. Write “T” or “F” on the answer sheet, then click on each box to mark your answer. Click for the correct answer a) Hypertension b) Type 1 diabetes c) Osteoarthritis d) Ovarian cancers e) Coronary heart disease a b c d e

31. What is childhood obesity? Source: 1998-2005 Self Realization Publications

32. Obesity in childhood has reached epidemic levels. In the US, it is the most common nutritional disorder in children. Developing countries are also affected as the prevalence rises among children of urban dwellers who emulate the ‘affluent western lifestyle’ Defining childhood obesity (1) • As in adults, the WHO uses the body mass • index (BMI) as the standard definition of • obesity in children. • BMI is calculated with the same formula for children and adults, but theresults are interpreted differently: • BMI for children, also referred toas BMI-for-age, is gender and agespecific • BMI changes dramatically with age in children as body fat changes with growth, and between girls and boys with maturity BMI-for-age, gender specific growth chartsused for children and teens 2 – 20 years of age.

33. Defining childhood obesity (2) In children, obesity is defined as a BMI greater than the 95th percentile for age while overweight is a BMI greater than the 85th percentile for age • BMI-for-Age is used for children and teens because of their rate of growth anddevelopment. It is a useful tool because: • BMI-for-age in children and adolescents compares well to laboratory measures ofbody fat • BMI-for-age can be used to track body size throughout life

34. Risk factors for childhood obesity • obesity in one or both parents • infants of diabetic mothers • children from single parent families and families with fewer children • higher birth weight and rapid growth during infancy are associated with an increased prevalence of obesity • formulafeeding during infancy(breast feeding in women who didnot smoke during pregnancy [but not in women who smoked duringpregnancy] was significantly associated with a reduced riskof obesity) • sedentary lifestyle – increase TV viewing, computer games, car rides, including a reduction in number of mandatory physical education classes in schools especially in the US • increase consumption of sugar sweetened drinks, soda, snacks, energy dense fast food in large portions

35. The relationship between childhood and adult obesity Born in the 60’s with a birth weight of 2.7kg (normal weight), she quickly became plump in infancy. Neither parent was overweight (father 82.6kg and1.52m; mother50.8kgand 1.52m) Aged 13 – bridesmaid at wedding From the age of 7, she was significantly heavier than her peers. In her early teens, she “weighed 88.9kg” and was advised by her paediatrician to join a slimming club. The weight gain persisted till adulthood. She is currently on nine different medications for obesity related problems Married at age 40 weight - 178 kg, Height - 1.65m BMI = 66 kg/m2 Thirty percent of childhood obesity leads toadultobesity and 70% obese adolescents become obese adults. The longer a child remains obese beyond age 3years, the more likely that the obesity will persist into adulthood. This true life story illustrates this – reproduced with the kind permission of Mrs. S.

36. The relationship between childhood and adult obesity Now that you have read this story, list 5 obesity-associated problems that may occur in this woman. • Mrs S. actually developed • hypertension • type II diabetes • hypothyroidism • menorrhagia • recurrent cellulitis • Other possible problems include: • osteoarthritis • stroke • metabolic syndrome • coronary heart disease • menstrual disorders • psychological disorders • cancers – ovarian, endometrial, breast, cervical, prostate

37. End of Section 5 You have come a long way! This is the end of the fifth section. Please answer question 8. Do remember to write your answers on the mark sheet before looking at the right answer!

38. Question 8: The following are statements about childhood obesity. Write “T” or “F” on the answer sheet, then click on each box to mark your answer. Click for the correct answer a) obesity is not a problem in children b) BMI-for-age is used for children and teens because of their rate of growth anddevelopment c)the use of BMI to define obesity does not depend on gender d)BMI-for-age in children and adolescents compares well to laboratory measures ofbody fat e) the longer a child remains obese beyond age 3 years, the more likely that the obesity will persist into adulthood a b c d e

39. Management of obesity • Effective management of obesity requires long-term strategies and an integrated, multi-disciplinary approach that includes community-based support for behavioural modification including diet and exercise. Research over the last decade indicates that a 5-10% reduction in body weight is sufficient to significantly improve medical conditions associated with obesity, such as hypertension, diabetes mellitus, and elevated cholesterol levels. • Currently there is lack of evidence of effective programmes for integrated management of obesity. But the following management options for the management of obesity exist: • dietary modification • behavioural modifications • physical activity • pharmacotherapy • bariatric surgery • As always, “prevention is better than cure”. Recently the UK government has set a target to halt the rise in obesity in children aged≤11 by 2010. Strategies for the prevention of childhood and adult obesity may need to address factors during or before infancy that are related to infant growth.

40. Dietary modification the most common and conservative treatment for obesity utilizes a nutritionally balanced, low calorie diet diet must include more fruit and vegetables, nuts, whole grains and exclude fatty and sugary foods weight-loss programs recommend diets consisting of 1,200 to 1,500 calories per day, usually in the following proportions: 60 percent carbohydrate, 30 percent fat, and 10 percent protein individuals must be carefully screened and medically supervised while on the diet(the degree of weight loss being dependent on individuals ability to adhere to dietary recommendations) studies have shown that meal replacements are often more effective than very low calories diets, resulting in an increase in the amount of initial weight loss and enabling dieters to maintain their weight loss Management options (1)

41. Management options (2) Behavioural modifications • many eating and exercise habits combine to promote weight gain. keeping a food diary that records times, places, activities, and emotions may be linked to periods of overeating or inactivity will reveal areas needing modification • lifestyle modification is best achieved when the affected individual is motivated, enthusiastic and supported to achieve set goals • patients are helped to avoid eating while on their feet, watching TV or playing games. Eat home cooked meals rather than fast foods • motivated to walk rather than use cars, escalators, lifts. Reduce TV, computer game hours, and use of energy saving devices Physical activity • research clearly indicates that regular exercise is the single best predictor for achieving long-term weight control • regular exercise leading to weight loss has been shown to improve blood pressure control, blood sugar levels in diabetics and other obesity-related complications

42. Management options (3) • Pharmacotherapy • It is recommended that anti-obesity drugs be used only : • in individuals aged 18-75yrs with a BMI of 30kg/m2 or more • in individuals with a BMI of ≥27kg/m2 with existing risk factors such as diabetes, cardiac disease, obstructive sleep apnoea or hypertension • in individuals with a BMI of >30kg/m2, in whom at least 3 months of managed care (supervised diet, exercise, and behaviour modification) fails to lead to significant reduction in weight • Two drugs have been licensed for use in the treatment of obesity: • Orlistat - prevents fat digestion and absorption by binding to gastrointestinal lipases; useful for those with a high intake of fat • Sibutramine - reduces appetite and increases thermogenesis; recommended for those who cannot control their appetite • These drugs should not be used as sole therapy for obesity. Their use requires strict regular monitoring and must be discontinued if weight loss is <5% after 12 weeks of use or weight gain recurs while on the drugs • Anti-obesity drug treatment should not be used beyond a year and never beyond two years as few studies have examined the consequences of their long-term use • Gradual reversal of weight loss is known to occur on stopping pharmacotherapy

43. Management options (4) Bariatric surgery • Surgery may be a weight-loss option for patients who are severely obese (with a BMI of  40 kg/m2 or those with BMI  35kg/m2 who suffer from serious medical complications). • There are two accepted surgical procedures for reducing body weight: gastroplasty and gastric bypass;both reduce the stomach to a small pouch that markedly limits the amount of food that can be consumed at any one time. • Studies show that there is weight loss of 25 to 30% over the first year post operatively with rapid normalization of blood pressure and glucose in patients with hypertension and diabetes. This is maintained for about five years after surgery. However, longterm monitoring is needed and surgery is not without attendant operative risks.

44. End of Section 6 Well done! This is the last of the sections. Please answer questions 9 and 10. Do remember to write your answers on the mark sheet before looking at the right answer!

45. Question 9: Answer the following questions on the management of obesity Click to Reveal Answers • List the current management options for obesity b) Surgery is sometimes considered in the management of obesity, • list the criteria for surgery • what surgical options exist?

46. Question 10: Mark the following statements as either True or False Click for the correct answer • obesity management requires an integrated multi-disciplinary approach • regular exercise is the single best predictor for achieving long-term weight control • diet must exclude more fruit and vegetables, nuts, whole grains and include fatty and sugary foods • the criteria for use of pharmacotherapy is a BMI > 20 kg/m2 with persistent co-morbidity • a 5-10% reduction in body weight is sufficient to significantly improve medical conditions associated with obesity a b c d e

47. Obesity is the excessive accumulation of body fat, best defined by the Body Mass Index (or Quetelet's Index). BMI is the universal and convenient measure of obesity. It is calculated as weightdivided by heightsquared (kg/m2). The BMI-for-age is used to assess obesity in children. In adults (age >18years), obesity is defined by a BMI of  30 kg/m2, and overweight by a BMI between 25 and 29.9 kg/m2. A child with a BMI-for-age >95th percentile is obese while one with a BMI-for-age >85th percentile is overweight. The longer a child remains obese beyond age 3 years, the more likely that the obesity will persist into adulthood. 30% of obese children are also obese as adults. 70% obese adolescents end up as obese adults. Obesity is believed to result from a complex interplay of several factors; genetic,environmental (lifestyle and dietary), cultural, socio-economic, psychological and medical conditions. Obesity is a known risk factor for severallife-threatening, chronic medical and metabolic conditions: hypertension, coronary artery disease, stroke, type II diabetes, cancers. A 5 - 10% reduction in body weight has been shown to significantly improve medical conditions associated with obesity. What Have I Learnt about Obesity? (1)

48. Obesity has reached epidemic proportions in several developed countries of the world and is also creeping up in urban cities of the underdeveloped world. Globally, there are more than 1.1 billion overweight adults, and at least 312 million of them are clinically obese. 10% of all children worldwide are either overweight or obese, while 17.6 million children under the age of five are estimated to be overweight. Rapid urbanization and economic development have led to changing lifestyles and diets across the world which promote excessive weight gain. An increasing incidence of obesity is also being seen in the poor, developing countries of the world Increase body weight is now the sixth most important risk factor contributing to the overall burden of disease worldwide What Have I Learnt about Obesity? (2)

49. Baird J, Fisher D, Lucas P, et al.Being big or growing fast: systematic review of size and growth in infancy and later obesity. BMJ 2005; S1:468-583 Bray G A, Popkin B M. Dietary fat intake does affect obesity! Am J Clin Nutr. 1998, 68:1157-73 Calle EE, et al. BMI and mortality in prospective cohort of U.S. adults. New England Journal of Medicine.1999;341:1097–1105. Cole TJ and Rolland-Cachera MF. In: Childhood and Adolescent Obesity. Burniat W, Cole T, Lissau I and Poskitt (Eds). Cambridge University Press, 2002 Haslam DW, Jones WPT. Obesity. Lancet 2005; 366:1197-1209 Garrow JS, Webster J. Quetelet's index (W/H2) as a measure of fatness. International Journal of Obesity. 1985;9:147–153. Gallagher D, et al. How useful is BMI for comparison of body fatness across age, sex and ethnic groups? American Journal of Epidemiology 1996;143:228–239. Rudolf M C J, Hochberg Z, Speiser P. Perspectives on the development of an international consensus on childhood obesity. Arch Dis Child 2005; 90:994-996. Stamatakis E, Primatesta P, Chinn S et al. Overweight and obesity trends from 1974 to 2003 in English children: what is the role of socioeconomic factors? Arch Dis Child 2005; 90:999-1004 World Health Organization. Physical status: The use and interpretation of anthropometry. Geneva, Switzerland: World Health Organization 1995. WHO Technical Report Series WHO Obesity; Preventing and managing the global epidemic. Report of a WHO Consultation on Obesity. Geneva, 3-5 June 1997 www.who.int/nutr; www.cdc.gov/growthcharts; www.corbis.com; Cartoon characters from theWeightWise campaign of the BritishDietetic Association. Drent ML, van der Veen EA. Lipase inhibition: A novel concept in the treatment of obesity. Int J Obes Relat Metab Disord 1993; 17:241-244. Sources of Information/images and References