Obesity

1. Obesity .Julio L. Cádiz Velázquez. MD, MPH, SCP

2. 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

3. 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

4. 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

5. 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)

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

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

8. 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

9. 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.

10. 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 600 million of them are clinically obese • 10% of all children are either overweight or obese, while 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.

11. Recent increase in the prevalence of obesity in the USA (1) Source: U.S. Center for Disease Control

12. Recent increase in the prevalence of obesity in the USA (1) . Source: U.S. Center for Disease Control

13. Recent increase in the prevalence of obesity in the USA (1)

14. Contries with more men obesity • China • USA • Brazil • Russia • India • Mexico The Lancet 2014

15. Contries with more women obesity • China • USA • India • Russia • Brazil • Mexico The Lancet 2014

16. Puerto Rico • Overweight and Obesity: 67% • Childs (2 y/o to 5 y/o): • Overweight: 14.9% • Obesity: 17% • Adolescent: • Overweight: 14% • Obesity: 11% Behavioral Risk Factor Surveillance System (BRFSS.)

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 Development 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 2014, the U.S. spent $117 billion on obesity (9% of the national total health budget) The morbidity and mortality burden of obesity: Overall, about 2.8 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. 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 : Genetic factors Socio-economic (lifestyle and diet) Cultural factors Psychological and medical factors Calories in and calories out – the imbalance

23. Genetic factors • We know that obesity tends to run in families, suggesting a genetic cause. Although, families also share diet and lifestyle, both of which contribute to obesity, research has shown that genetic factors account for as much 80% of the link between heredity and obesity. • Studies in adoptees and twins strongly support this link: • Adults who were adopted aschildren have weights closer to their biological parents than to theiradoptive parents • Monozygotic (identical) twins show a much stronger correlation in body weight than dizygotic (non-identical) twins Source: NHS Health Scotland

24. Diet Apart from our genes, environmental factors also contribute to the recent surge in obesity. The following changes in diets across the world play a major role: increase in consumption of energy dense foods – containing animal fats decrease consumption of complex carbohydrates and fibre - coarse grains, fruits increase intake of alcohol and salt In recent years, societies of the western world have enjoyed an over abundance of food – so people feast on larger portions at low prices. As this “affluence” creeps into the urban centres of the developing world, we are beginning to see a rise in obesity. The growth of the fast food industry has made an abundance of high fat, inexpensive meals widely available, resulting in a shift in stable foods from low quality staples (cassava, corn) to high quality refinedstaples (processed rice, wheat). Socio-economic factors and lifestyle (1)

25. Socio-economic factors and lifestyle (2) • Exercise – or the lack of it… • Urbanization and economic development in the western world have led to the ‘affluent • lifestyle’ which include less physical activity. • Examples include: • the car - driving to work and school instead of walking or cycling • TV and computer games - long hours sitting watching • energy/time saving devices and machines (e.g. washing machines) reduce manual labour in the home Source: http://www.aces.edu/dept/extcomm/newspaper/child-obesity.html

26. Socio-economic status Socio-economic status has been found to relate to the riskof obesity in bothadults and children. Although obesity is a feature of “affluence”, in the UK, obesity is more common in poorer families. An increasing incidence of obesity is being seen in the poor, developing countries of the world. In South Africa, obesity was found to be increased among the poorest women. What are the reasons for this? poorer families tend to eat energy dense, convenience foods – often they have no alternative as these tend to be low cost foods people from lower socio-economicstrata participate less in sportsor physical activity in generaland have lower weight control awareness Socio-economic factors and lifestyle (3)

27. The cultural practice of placing youngwomen in ‘fattening rooms’ for months before marriage or after childbirth. In fattening rooms, the daily routinewas tosleep, eat and grow fat. The women spent their time resting like beached whales and gorging on a high-fat, high-calorie diets. This practice has greatly reduced in recentyears in south-eastern parts of Nigeria. Cultural factors (1) • In certain cultures of the world ‘big is beautiful’. Obesity was a sign of wealth and well-being in the past and still is in many parts of Africa. In contrast to many Western cultures where thin is in, many culture-conscious people in these parts hailed a woman's rotundity as a sign of good health, prosperity and allure. Source: Where BIG is beautiful! Women who are not fattened are CURSED! National Examiner may 1, 2001 page 10

28. The Japanese sumo wrestlers are well known obese individuals. They achieve their big size from an an elaborate rice- based diet, fat-rich stew and lots of sleep. Cultural factors(2) Source: Print by Kunisada II

29. Psychological factors are known to influence eating habits. Many people eat in response to negative emotions, such as anger, sadness orboredom. Metabolic and organic factors including drug therapies have been associated with obesity as metabolic rate slows down, the tendency to gain weight increases. Slow metabolic rate is found with reduced physical activity, advancing age, and in females compared to males certain medical conditions are associated with obesity: depression, hypothyroidism,Cushing’s syndrome, pituitary tumours, cerebral diseases including infections, hydrocephalus, as well as certain chromosomal anomalies – Down syndrome, Klienfelter syndrome drugs that can cause weight gain include: corticosteriods, anti-depressant drugs, antipsychotics, oral contraceptive and progestagenic compounds, oral hypoglycaemic agents, insulin, antihistamines,  blockers, pizotifen Psychological and medical factors

30. Obesity - a known risk factor for severallife-threatening medical conditions (1) • Diabetes Mellitus (DM) : • the relation between obesity and type II diabetes (non-insulin dependent diabetes) has been established since the 1970s • excess fat deposits in obesity is associated with insulin resistance, glucose intolerance and premature type II diabetes • 90% of patients with type II diabetes have BMI higher than 23kg/m2 • the risk of type II DM is greatly increase where there is a history of early weight gain (childhood obesity), android obesity, positive family history of DM, and maternal history of gestational DM Hypertension: • the risk of hypertension is five times higher among the obese than the non-obese population • studies confirm that 85% of hypertension arises in people with BMI values >25kg/m2 • increase body mass is associated with: increase blood volume, increase blood viscosity, increase release of angiotensinogen from adipocytes resulting in increase blood pressure • dietary fats consumed by obese individuals induce a direct rise in body cholesterol levels and blood pressure

31. Obesity - a known risk factor for severallife-threatening medical conditions (2) • Coronary artery disease and stroke: • The effect of obesity on cardiac function is thought to be due to a combination of hypertension, diabetes mellitus, dyslipidaemia and increased fat mass • The risk increases as BMI values exceed 21.0 kg/m2. Studies show that heart failure in 14% women and 11% men is due to obesity Cancers: • the risk for cancers is more among the obese than the non-obese population • estimates indicate that overweight and inactivity account for a quarter to a third of cancers of the breast, colon, endometrium, kidney and oesophagus Reproductive abnormalities: • excess fat accumulation is linked with a rise in free oestrogen concentrations from the activity of the enzyme aromatase on sex hormones in adipose tissue • this high oestrogen level affects normal hormonal balance and accounts for menstrual irregularities, ovarian dysfunction, impotence and impaired fertility amongst men • 6% of primary infertility is attributed to obesity in women • pregnancy complications, maternal and infant deaths, infant macrosomia have been found to increase by 3-10 fold in obese women

32. Obesity - a known risk factor for severallife-threatening medical conditions (3) Psychological features of obesity: • In US women obesity increases the risk of being diagnosed with major depression by 37% • Low self esteem, anxiety, depression and obsessive behaviours are common among obese individuals especially women • Obesity and depression are linked closely with two eating disorders: night eating syndrome and binge eating disorder (including bulimia nervosa). These need early recognition and early psychotherapy Respiratory complications: • Obesity worsens existing respiratory disease • Sleep apnea occurs in the obese due to mechanical obstruction from bulky fatty tissue around the neck • Obesity has recently been sited as a risk factor for atopy Others • Obesity leads to joint pains and arthritis of the weight bearing joints – hips, knees • Obesity is also closely linked with the rapidly rising prevalence of non-alcoholic steatohepatitis in the developed world • The incidence of gall bladder disease and gall stones is higher in women with BMI of > 45kg/m2

33. Other effects of obesity (1) • Increased body weight is now the 6th most important risk factor contributing to the overall burden of disease worldwide. Regions particularly affected are eastern Europe and America. • Obese individuals have a reduced life expectancy. Recent studies show that obesity reduces life expectancy by 7 years at age 40. The UK government’s recent estimates show that a BMI of 25kg/m2 reduces the life expectancy of English men by two years. • Obesity is associated with an increase risk of premature death from several chronic diseases; as body weight increases to >20% of expected weight for height and age, the mortality risk has been shown to increase by 20% in males and 10% in females. • Apart from the ill health, premature death anddisability resulting from obesity-related medical conditions, several billions of dollars are expended on their treatment. Obesity accounts for 5-10% of the total health care budget in several developed countries.

34. Obesity has serious deleterious effects on quality of life. There is the social stigma associated with obesity 20% of obese people are less likely to marry than their thinner counterparts the annual household income of obese people is nearly $7,000 less than that of thinner people an obese person is 10% more likely to live a life of poverty With obesity there is restricted activity, exercise intolerance, pain, worry, low self esteem, and depression Other effects of obesity (2)

35. 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 BMI changes dramatically with age in children as bodygender and agespecific • 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.

36. 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

37. 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. • 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. • Thirty percent of childhood obesity leads toadultobesity and 70% obese adolescents become obese adults.

38. 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. • Effective programmes for integrated management of obesity: • dietary modification • behavioural modifications • physical activity • pharmacotherapy • bariatric ssurgery • As always, “prevention is better than cure”, strategies for the prevention of childhood and adult obesity may need to address factors during or before infancy that are related to infant growth.

39. 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)

40. 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

41. 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 apnea 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

42. 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.

43. Obesity is the excessive accumulation of body fat, best defined by the Body Mass 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. 5 - 10% reduction in body weight has been shown to significantly improve medical conditions associated with obesity. What Have I Learnt about Obesity? (1)

44. 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 600 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)

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46. Thank you