1. Epidemiology Childhood Obesity
Abdelaziz Elamin, MD,PhD,FRCP,FRCPCH
Professor of Child Health
University of Khartoum, Sudan
Consultant in pediatric Endocrinology & Clinical Nutrition
If you see (Supercourse), this means that one of the Supercourse team annotated that slide, not the author. Some URLs also provided by Supercourse team.
Original PowerPoint file of this lecture

2. Epidemiology
The study of how a disease or health outcome is distributed in populations and what factors influence or determine this distribution.
There are two fundamental assumptions in epidemiology:
Human disease is not random
Human disease has causal and preventative factors that can be identified through scientific investigation of different populations or subgroups of individuals within a population (Hennekens, 1987).
The primary goal of epidemiology is to identify the determinants of health and disease to decrease mortality (death) and morbidity (a diseased condition or state) within a population (Kuller, 1987). Physical Activity Epidemiology, therefore, focuses on physical activity within populations and investigates how physical activity levels impact health and disease to decrease mortality and morbidity. Physical Activity Epidemiology typically incorporates both the assessment of physical activity, as well as, intervention efforts focusing on increasing physical activity.
Recommended Readings:
Gordis L (2000). Epidemiology (2nd ed.). Philadelphia, PA: W.B. Saunders Company.
Hennekens CH, Buring JE (1987). Epidemiology in medicine. Boston: Little, Brown: 3-15.
Kuller LH (1987). Relationship between acute and chronic disease epidemiology. Yale Journal of Biology and Medicine; 60:

3. Definition
Obesity is a serious degree of Overweight caused by excessive storage of fat & usually measured using a Body Mass Index .
BMI is defined as body weight in kilograms divided by the square height in meters.
Definitions of obesity vary, but the most agreed up is the measure of Body Mass Index
(Supercourse)

4. WHO: Overweight and Obesity
For Adolescents & Adults
BMI between 18.5 & 24.9: Healthy weight
BMI between 25 and 29.9: Overweight
BMI 30 & above: Obese
BMI 40 & above: Morbid obesity
For Children
BMI between 5th & <85th percentile: Healthy weight
BMI between 85th & 95th percentile: Overweight
BMI >95th percentile: Obesity
Obesity results from an imbalance in caloric intake relative to caloric expenditure. This imbalance causes fat to accumulate. Researchers usually define overweight and obesity in terms of an individual’s body mass index, or BMI. BMI is calculated by dividing a person’s weight in kilograms by his or her height in meters squared [kg/m2]. A person with a BMI over 25 is classified as overweight, while a person with a BMI of 30 or above is considered obese.
For example, a 6-foot (~1.8 m) tall man who weighs 180 pounds (~82 kg) has a BMI of about 24, which is at the upper end of the normal range. At 200 pounds (~91 kg), he has a BMI of about 27 and he is classified as overweight. At 225 pounds (~102 kg), he has a BMI of over 30, and he is obese.
Overweight is defined somewhat differently in children and adolescents. After BMI is calculated, it is plotted on growth charts -- based on national surveys compiled before the recent increase in obesity -- to obtain a percentile ranking. If a child’s BMI is above the 85th percentile for his or her age, then he or she is at risk of becoming overweight. If a child’s BMI is above the 95th percentile, the child is overweight. There is no generally accepted definition for obesity, as distinct from overweight, in this age group.
It is possible to have a high BMI and be healthy. For example, people who are athletic and have large amounts of muscle may have a BMI over 25, but are healthy. Also, BMI measurements cannot be used on pregnant women. Nevertheless, BMI is a useful tool.

5. Overweight and Obesity in the US
Epidemic state in the United States
25% of children are obese
More than ½ of all adults are overweight and nearly a quarter are obese
Rate of obesity has doubled since 1960 and continues to rise
If current trends continue, all Americans will be overweight by the yr 2030.
The problem of obesity in children in the US is becoming great and great. (Supercourse)

6. Patterns Of Overweight & Obesity Globally For Nationally Representative Samples (Percentage overweight + Obese)
>51%
<10%
41-50%
31-40%
21-30%
10-20%
Arctic Ocean
Arctic Ocean
North Pacific Ocean
Obesity world wide is becoming a major problem. The US leads the way, but Russia, Chile, Mexico and many countries of Europe are demonstrating an epidemic of obesity (Supercourse)
Indian Ocean
South Pacific Ocean
South Atlantic Ocean
© B.Popkin 2009

7. BMI Distribution Shifts among Mexican women 18-49 y
(National Surveys 1988, 1999 y 2006) .1
1988
1999
.08
2006
.06
K density BMI
.04
Obesity is rising very quickly in Mexico, especially in Mexican women. (Supercourse)
.02 10 15 20 25 30 35 40 45 50 55 60 65
BMI (Kg/m2)
From Juan Rivera

8. BMI Distribution Shifts Among Chinese Adults,
ages 19 and Older
Percent
In China there has also been a marked shift from lower BMI levels to much higher levels (Supercourse)
China Health and Nutrition Survey. Males: ; Females

9. Africa in 30 years has gone from undernutrition and are now facing the problem of overnution (Supercourse)

10. Childhood Obesity
MORE THAN 1 IN 4 Of World CHILDREN IS OVERWEIGHT or OBESE.
CHILDHOOD OBESITY IS INCREASING EVEN IN THE POOR COUNTRIES.
OBESE CHILDREN GROW AS OBESE ADULTS.
The metabolic syndrome & IRS IS PREVALENT IN OBESE ADOLESCENTS same
Degree as in adults
We are seeing in the US and world that those who are poor, of lower socioeconomic status, the rates of obesity are dramatically increasing (Supercourse)

11. Childhood Obesity Prevalence
In USA :
Doubled in children 6-12 year .
Tripled in adolescents.
20% of 6-19 year are obese.
Worldwide :
Range from ( 10% to 25%).
There has been an amazing doubling of obesity in the USA, and a tripling in teenagers. (Supercourse)

12. Trends in U.S. Child and Adolescent Overweight20 20 15 15
6-11 years old
Percent
Percent 10 10
12-19 years old
Since the late 1970s, the rates of overweight among children and adolescents have risen dramatically. Recall that overweight is defined as BMI greater than or equal to the gender- and weight-specific 95th percentile from historic growth charts.
Source: National Health Examination Surveys II (ages 6-11) and III (ages 12-17), National Health and Nutrition Examination Surveys I, II, III and , National Center for Health Statistics, CDC. 5 5

13. Annual Absolute Change in the Prevalence of Childhood Overweight and Obesity in 7 Countries from 1985/1995 to 1995/2006 (IOTF definition for childhood obesity)
Annual percentage change
There has been an amazing increase in obesity in children in both Australia and Mexico. Russia is the only country where the rate of obesity either stayed even or dropped a little bit (Supercourse)
Popkin (2007) nature reviews, cancer 7:61

14. Childhood Obesity in Germany
(title appears) The airwaves have been filled of late with two public health pronouncements that are increasingly linked by cause and effect. The first is that physical activity has a profound positive physiological effect on the body. The second is that childhood obesity is growing in epidemic proportions.
(rest of slide appears) That childhood obesity is on the rise is undeniable. The rates have been advancing steadily for the past 35 years with obesity growing from 4% to 13% in 6 to 11 years olds and from 5% to 14% in 12 to 19 year olds. In just two decades, the number of obese children has doubled. 1.
Source: National Center for Health Statistics, 1999 National Health and Nutrition Examination Survey. 14

15. Percent increase in Prevalence of Childhood obesity in Sweden
( )
The rise of obesity in Sweden (Supercourse)

16. Prevalence of Childhood Obesity in the UK (1995-2002)
The rise of obesity has not been as large in the UK (Supercourse)

17. Prevalence of Childhood Obesity in Italy25 20 15
Prevalence (%) 10 5
NHANES III ( ),, NHANES II ( ),, NHANES I ( )
NHES III ( )
NHES II ( )
National Health and Nutrition Examination Survey (NHANES)
1964
1974
1984 -
1994
Boys over wt
Girls over wt
Boys obese
Girls obese

18. Obesity In Developing Countries
The burden of obesity & its complications is shifting rapidly towards the poor.
Simultaneous malnutrition & overweight exist.
Obesity is now 4X more common than malnutrition in some developing countries.
Evidence from Brazil & China points to a clear shift in obesity and overweight from middle class to the poor.
These observations are replicated across many countries in Asia, Africa & Latin America.
Poverty & unemployment, combined with poor knowledge of healthy food habits encourage consumption of cheap high energy snacks and soft drinks.
Whatever little they earn is spent on junk food due to the impact of western fast food culture & advertisements that are rampant on TV which is seen more avidly in the slums.

19. Country % Overweight % Obesity Iran 32.0 14.5 Jordon 17.3 8.9 Oman
Prevalence of Childhood Obesity in the Region
(9-18 yrs)
Country
% Overweight
% Obesity
Iran
32.0
14.5
Jordon
17.3
8.9
Oman
19.2
9.6
Syria
16.5
11.2
Sudan
12.4
7.6
The middle east has seen a rapid increase in childhood obesity, with over 46% overweight or obese in Iran (Supercourse)

20. Causes of Childhood Obesity
Genetics
Pathological causes
Socioeconomic
Childhood obesity
Many different factors contribute to increased obesity rates in children (Supercourse)
Behavioral
Nutritional 20

21. Obesity: Environmental Influence
Current environment
BMI %
What is responsible for this sudden increase in the number of obese people in the U.S.? Obesity most likely results from an interplay between genes and the environment. However, the recent explosion in the prevalence of obesity has occurred too quickly to be explained solely by changes in our genes. One hypothesis is that, in the past, humans who were able to accumulate fat when food was plentiful were better able to survive during times of food scarcity. Now, however, in the U.S. and many other countries, food is plentiful and foods that are high in calories but often low in nutritional value tend to be relatively inexpensive. Furthermore, most people engage in far less physical activity than did previous generations. Ironically, the ability to accumulate fat during times of plenty – which was originally thought to confer a benefit – has become a detriment to our health. Research supported by the NIDDK has led to improved understanding of the factors contributing to this complex condition.
G.S. Barsh, I.S. Farooqi, S. O’Rahilly. Nature 404: 644, 2000
Past environment
Genetic susceptibility

22. TIME 2000 SPECIAL ISSUE WILL WE KEEP GETTING FATTER? November 8, 1999
The media has picked up the concern of obesity, for example in Time Magazine (Supercourse)
WILL WE KEEP GETTING FATTER?

23. Cause of Present Obesity Epidemic
Energy intake unequal energy output
Decreasing physical activity
Increasing consumption of calorie dense foods
More meals eaten outside of home
Increased portion sizes
Lack of concern about obesity
There are many factors that contribute to the US and global increase in weight (Supercourse)

24. Obesity Is Caused by Long-Term Positive Energy Balance
Fat Stores
Even a small imbalance of calories in and calories out can cause a rise in weight over years or decades (Supercourse) 24

25. International Journal of Obesity (2004) 28, S21–S28. doi:10. 1038/sj
International Journal of Obesity (2004) 28, S21–S28. doi: /sj.ijo
Epidemiology of childhood obesity—methodological aspects and guidelines: what is new?
Y Wang

26. obesity Energy Out Energy In Weight gain:
Weight gain happens when you consume more energy (calories from food and drinks) then you actually expend through daily activities and exercise.
Our society has become more dependant upon the car for transportation, we watch more TV, and spend tons of time using other media including computers and video games. At the same time, our portion sizes have gotten larger, and foods that are rich in calories have become easier to access and are cheaper (Lancet, 02) 26

27. Changing Dietary Habits
Increased intake of caloric sweeteners & edible oil
Increased intake of processed foods, refined carbohydrates & salty high fat snacks
Reduced intake of fruits and vegetables
Increased global beverage due to:
increased accessibility,
lower price,
income dynamics and marketing
The diet of the US has markedly changed in 50 years, and the same type of changes have been seen in many countries (Supercourse)

28. From Traditional food to Modern Meals
American Journal of EpidemiologyVolume171, Issue12 Pp
Changing Influences on Childhood Obesity: A Study of 2 Generations of the 1958 British Birth Cohort
Angela Pinot de Moira, Chris Power and Leah Li

29. From Traditional to Modern Snacking
Snacking has dramatically changed to high caloric drinks, and snack foods (Supercourse)

30. From Traditional Food Marketing to Modern Food Supermarkets
Supermarkets have increased the types of foods available, at the same time the cost per calorie has been substantially reduced (Supercourse)

31. Decreased Physical activity
Excess TV; computer, & play station time
Children are home alone (dual income parents)
Decreased physical activity at school & at home
Transportation by car or school bus
Neighborhood safety
Few public parks, sidewalks, swimming pools ..etc
Availability of school resources after school

32. Instead of walking to mosques, churches or temples, people are taking their cars. (Supercourse)

33. No matter how short of a distance, we still avoid walking (Supercourse)

34.
Childhood obesity, prevalence and prevention
Mahshid Dehghan et al.

35. From Traditional to Modern Leisure
In earlier days we were much more active as children (Supercourse)

36. Trends in Physical Education45 40 35
% of graders
enrolled in Daily PE 30 25 % 20
In the US the number of high school children engaged in daily PE is markedly reduced (Supercourse) 15 10 5
1991
1993
1995
1997
(CDC 2000 Review)

37.
Clinical Review
Obesity in children. Part 1: Epidemiology, measurement, risk factors, and screening
Ruth R Kipping et al.

38. Obesity Hazards What bothers you the most? Anthropometric parameters
Comorbidities
Obesity is associated with future development of chronic diseases such as diabetes and CHD (Supercourse)

39. Health Complications of Obesity
Stroke
Idiopathic intracranial
hypertension
Pulmonary disease
abnormal function
obstructive sleep apnea
hypoventilation syndrome
Cataracts
Coronary heart disease
Pancreatitis
Diabetes
Nonalcoholic fatty liver disease
steatosis
steatohepatitis
cirrhosis
Dyslipidemia
Hypertension
Gynecologic abnormalities
abnormal menses
infertility
polycystic ovarian syndrome
Gall bladder disease
Obesity is a problem in the U.S. for two main reasons. The first is that a large number of health problems are associated with obesity. They include high blood pressure, cardiovascular disease, stroke, arthritis, and many others. The multitude of co-morbidities associated with obesity reflects the complexity and diversity of systems that contribute to energy balance. Obesity is also associated with several diseases within the research mission of the NIDDK, including nonalcoholic fatty liver disease and type 2 diabetes.
Image modified from one appearing in National Geographic magazine.
Cancer
breast, uterus, cervix, prostate, kidney
colon, esophagus, pancreas, liver
Osteoarthritis
Skin
Phlebitis
venous stasis
Gout 13 13

40. RED FLAG
Obesity and overweight account for more than 300,000 premature deaths annually in United States, 2nd only to tobacco-related deaths.
Obesity would surpass tobacco as the leading cause of death worldwide in the next decade.
Obesity is becoming one of the major health hazards (Supercourse)

41. The Bottom Line Obesity causes 300,000 premature
Reversing the Trend of Childhood Obesity
Donna F. Stroup et al.
Obesity causes 300,000 premature
deaths per year in the US
19-Apr-17
©M.Miqdady, M.D.

42. Complications Specific to Children …
Persistence of Obesity at Adulthood:
Overweight adolescents have a 70% chance of becoming overweight adults.
Increases to 80% if one or both parents are obese.
Obese 6 year old has a 25% chance of becoming obese adult
Obese 12 year old has a 75% chance of becoming a obese adult.
Obesity tracks very highly were obese children tend to become obese adults (Supercourse)

43. The probability of obesity in adults in relation to BMI at various ages during childhood16 15 12 11 10 9 17 19 55 75 67 26 52 69 83 77 36 20 40 60 80
100
Birth 1 to 3 6 18
Age of child (
years )
% obese as adults
BMI < 85th
BMI > 85th
BMI >95th
The tracking of BMI that occurs from childhood to adulthood is clearly shown in data from a study by Robert Whitaker (Children’s Hospital Medical Center in Cincinnati) and colleagues. They examined the probability of obesity in young adults in relation to the presence or absence of overweight at various times during childhood. For example, in children 10 to 15 years old, 10% of those with BMI-for-age < 85th percentile were obese at age 25 whereas 75% of those with a BMI-for-age > 85th percentile were obese as adults and 80% of those with a BMI-for-age > 95th percentile were obese at age 25. (The sample size for the study was 854.) This study clearly shows that an overweight child is more likely than a child of normal weight to be obese as an adult.
Other studies have shown this same trend of tracking occurring from childhood to adulthood.The likelihood childhood obesity persists into adulthood obesity is related to the age, the older the more likely, not the duration.
Adipocyte hypertrophy precedes hyperplasia ,(critical size then hyperplasia) wt loss is achieved by reduction in vol. Not # of adipocytes

44. Common Complications in Children
Metabolic Syndrome.
Hypertension
Fatty Liver .
Early Sexual Maturation.
Asthma
Sleep apnea
Childhood Obesity

46. “The first wealth is health.”
Evaluation and Management of Obesity in Children and Adolescents: Definition and Epidemiology
Thanks for your attention

47. Review Questions (Developed by the Supercourse team)
Russia is one of the few countries where children are becoming less obese. Why might this be?
In developing countries, what is more important, obesity or malnutrition and why?
Describe the concept of energy balance
What are the main diseases associated with obesity?
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