Epidemiology of Obesity Lecture handout by Prof Ashry

Epidemiology of Obesity Lecture handout by Prof. Ashry Gad Mohamed & Dr Amna Rehana Siddiqui Department of Family and Community Medicine

Objectives • Understand the terms overweight and obesity • Recognize the methods to diagnose overweight and obesity • Discuss the distribution of obesity by gender & age groups in Saudi Arabia & other settings • Know the determinants and consequences of obesity • Outline approach to control obesity

No body is exempted from obesity. It can be you.

Terms Obesity and Overweight • Obesity is excessive fat accumulation in adipose tissue to the extent that it can affect health • When a person is "overweight", it means that they have more body fat than they need for their body to function. • Weight ranges are greater than what is generally considered healthy for a given height • Such ranges of weight increase the likelihood of certain diseases and health problems.

Measuring Obesity

Body Mass Index (BMI) • Calculated from a person's weight and height. • Reliable indicator of body fatness for most people. • Inexpensive & easy-to-perform screening for weight categories that may lead to health problems. • Does not measure body fat directly, but correlates to direct measures of body fat like; – – Skin fold thickness underwater weighing dual energy x-ray absorptiometry (DXA) alternative for direct measures of body fat.

Obesity classification. • CDC, Obesity is further divided into three separate classes, with Class III obesity being the most extreme of the three. With a BMI of: You are considered: Below 18. 5 Underweight 18. 5 - 24. 9 Healthy Weight 25. 0 - 29. 9 Overweight 30 or higher Obese Obesity class BMI (kg/m 2) Class I 30. 0 - 34. 9 Class II 35. 0 -39. 9 Class III ≥ 40. 0 (Extreme Obesity)

Body Mass Index (BMI): Western Settings • BMI= Wt. (kg. ) / Ht. 2(meters 2) • BMI= Wt (lbs) / Ht 2 (inches) Height 5' 9" Weight Range BMI Considered 124 lbs or less Below 18. 5 Underweight 125 to 168 lbs 18. 5 to 24. 9 Healthy weight 169 to 202 lbs 25. 0 to 29. 9 Overweight 203 lbs or > 30 or higher Obese

Obesity Assessment • Increased body weight does not always equate to increased body fat. • For example, a professional football player could weigh 260 pounds and be six feet tall with no excess fat, just increased lean body mass.

Mortality Data and BMI • The mortality data is U - or J -shaped conformation in relation to weight distribution. • Notable racial spectrum • Ideal BMI for Asians is substantially lower than that for Caucasians. • For subjects with severe obesity (BMIs ≥ 40), life expectancy is reduced by as much as 20 years in men and by about 5 years in women. • Coexisting obesity and smoking are associated with even greater risks than these alone for premature mortality.

Disease Risk Associated With Different Levels Of BMI And Waist Circumference In Adult Asians Weight Categories BMI (kg/m 2) Obesity Class Disease Risk (Relative to Normal Weight and Waist Circumference) Men < 35 in (<90 cm) Women < 31 in ( < 80 cm) Underweight >35 in (>90 cm) 31 in (>80 cm) < 18. 5 Low Average Normal 18. 5 -22. 9 Average Moderate Overweight 23. 0 -24. 9 Moderate Increased Obesity 25 -29. 9 I Increased High Extreme Obesity ≥ 30 II High Very High Adapted from Redefining Obesity and its Treatment: The Asia-Pacific Perspective. WHO 2000 13

Global Prevalence of Obesity in Adult Males With examples of the top 5 Countries in each Region North America USA 31% Mexico 19% Canada (self report) 17% Guyana 14% Bahamas 14% % Obese 0 -9. 9% 10 -14. 9% 15 -19. 9% 20 -24. 9% 25 -29. 9% ≥ 30% Self Reported data European Region Croatia 31% Cyprus 27% Czech Republic 25% Albania (urban) 23% England 23% Eastern Mediterranean Lebanon 36% Qatar 35% Jordan 33% Kuwait 28% Saudi Arabia 26% South Central America Panama 28% Paraguay 23% Argentina (urban) 20% Uruguay (self report) 17% Dominican Republic 16% Africa South Africa 10% Seychelles 9% Cameroon (urban) 5% Ghana 5% Tanzania (urban) 5% With the limited data available, prevalence's are not age standardised. Self reported surveys may underestimate true prevalence. Sources and references are available from the IOTF. International Obesity Task. Force, London –January 2007 © South East Asia Pacific Region Nauru 80% Tonga 47% Cook Island 41% French Polynesia Samoa 33%

Global Prevalence of Obesity in Adult Females With examples of the top 5 Countries in each Region European Region Albania 36% Malta 35% Turkey 29% Slovakia 28% Czech Republic 26% Eastern Mediterranean Jordan 60% Qatar 45% Saudi Arabia 44% Palestine 43% Lebanon 38% North America USA 33% Barbados 31% Mexico 29% St Lucia 28% Bahamas 28% % Obese 0 -9. 9% 10 -14. 9% 15 -19. 9% 20 -24. 9% 25 -29. 9% ≥ 30% Self Reported data South Central America Panama 36% Paraguay 36% Peru (urban) 23% Chile (urban) 23% Dominican Republic 18% Africa Seychelles 28% South Africa 28% Ghana 20% Mauritania 19% Cameroon (urban) 14% With the limited data available, prevalence's are not age standardised. Self reported surveys may underestimate true prevalence. Sources and references are available from the IOTF. International Obesity Task. Force, London –January 2007 © South East Asia Pacific Region Nauru 78% Tonga 70% Samoa 63% Niue 46% French Polynesia

BMI and Body Fat • At the same BMI, women tend to have more body fat than men. • At the same BMI, older people, on average, tend to have more body fat than younger adults. • Highly trained athletes may have a high BMI because of increased muscularity rather than increased body fatness.

Abnormal Fat Distribution • Upper body subcutaneous fat is a marker for intra-abdominal fat in men and women. • Men accumulate upper body fat. • Women can accumulate upper & lower body fat

Measuring Body Fat depots can be measured with skin-fold calipers. • Males: Upper Chest, Upper Abdomen • Female: Triceps, Lower Abdomen, Thighs Waist Circumference: While standing place a tape measure just above the hipbones; after breathing out. Risk of heart disease and diabetes mellitus increases in • Males: > 40 inches (western Setting) > 35 inches (Asians) • Females: > 35 inches (Western Setting) > 31 inches (Asians)

Obesity & Overweight in Children & Adolescents • Overweight is defined as a BMI at or above the 85 th percentile and lower than the 95 th percentile for children of the same age and sex. • Obesity is defined as a BMI at or above the 95 th percentile for children of the same age and sex. 1

Obesity in Children & Adolescence • Children and particularly adolescents who are obese have a high probability of growing to be adults who are obese. • Obesity epidemic is expected in next decades • Adolescent obesity poses a serious risk for severe obesity during early adulthood,

Correlation: BMI and Adverse health • Overall morbidity and mortality increases exponentially at a calculated BMI of greater than 30. • At any given BMI women have a greater percent body fat than men, so other methods are also needed to assess body fat clinically.

Distribution of Obesity

Obesity by Gender 1999 -2003 % of Total population Reference: Last Slide; http: //www. economist. com/node/8846631

Obesity prevalence: Global • 250 million people (~ 7% of the world) are obese. • Overweight rate is 2 -3 times more of obesity • Socioeconomic status (SES) and prevalence of obesity are negatively correlated in developed countries • Correlation between SES and Obesity is reversed in many undeveloped countries

Obesity prevalence: International • The prevalence of obesity is increasing world wide • MONICA study from Europe reports that 15% of men and 22% of women are obese in Europe • Malaysia, Japan, Australia, New Zealand, and China detailed obesity epidemic in the past 2 -3 decades. • Middle Eastern countries; show a disturbing trend, with alarming levels of obesity often exceeding 40% and particularly worse in women than in men.

Epidemiology of Obesity in USA • About 100 million adults in the United States are at least overweight or obese. • 35% of women and 31% of men older than 19 years are obese or overweight. • 20 -25% of children are either overweight or obese, • Prevalence is greater in some minority groups • Obesity management costs about $100 billion / year, without the costs of various commercial dietary and weight-loss programs.

Demographic Prevalence of Obesity (BMI>30) : USA MMWR August 2010 % MMWR: Morbidity and Mortality Weekly Report CDC USA

Demographic Prevalence of Obesity in Saudi Arabia (BMI>30 kg/m 2) 1990 -1993 National Chronic Diseases metabolic Survey 1990 -93 MOH & King Saud University

Women’s obesity by educational attainment Marmot M, Clinical Medicine, 2006

Prevalence of overweight, obesity, and severe obesity in children & Adolescents (N=19, 317; age 5 – 18 years) Saudi Arabia 2005 Ref: El-Mouzan et al. Prevalence of overweight and obesity in Saudi children and adolescents Annals of Saudi medicine 2010; Vol 30 (3) : 203 -208

Figure 1 Percentage increase in BMI categories since 1986 (source: Behavioral Risk Factor Surveillance Survey; results adjusted for changes in population demographics for 2005. Source: Sturm R. Public Health 2007; 121: 492 -496 (DOI: 10. 1016/j. puhe. 2007. 01. 006 )

Regional (local) studies showing the prevlanece of obesity and overweight Author , and place of study Age group Khashoggi et al (1994)Attendees at PHC jedahh 11 -70 years Mean age 32. 2 852 female AL- Shammati et al (1994 b) Attendees at PHC, Riyadh Mean male = 34 Female 32 733 With back pain AL- Jassir et al (1998) Emploees of M. O. H Riyadh 20 and above No of subjects 1238 males Criteria used Prevalence among male % Prevalence among Female% Obese BMI >30 ---- 64. 3 Overweight BMI 25 -29. 9 ---- 26. 8 Obese BMI >30 47. 0 Obese BMI >30 51. 6 Overweight BMI 25 -29. 9 40. 3 ---- Obese BMI >30 18. 4 . . …

Causes of Obesity Primarily • Dietary intake • Physical Inactivity • Eating patterns • Eating environment • Food availability • Food packaging • Eating environment • Fast food linked to increased adiposity Some Secondary Causes • Hypothyroidism • Cushing’s Syndrome • Hypothalamic Obesity • Polycystic Ovarian Syndrome • Growth Hormone deficiency • Oral Contraceptives • Pregnancy related • Genetic Syndromes • Medication Related • Eating Disorder

Comorbidities

Genetic reasons for obesity • A mutant gene • A defective gene to produce Leptin ; a satiety hormone that influences the appetite control in hypothalamus • Role of mutant genes in defective receptor action is being studied

Causes of Obesity A defective ob gene In addition to deficient causes inadequate leptin production, leptin production. Thus, scientists also propose the brain receives an the possibility of under assessment of defective receptor body’s adipose stores action (via a leptin and urge to eat. receptor molecule on brain cells), which increases a person’s resistance to satiety.

Causes of Obesity • Characteristics of fast food linked to increased adiposity: – Higher energy density – Greater saturated fat – Reduced complex carbohydrates & fiber – Reduced fruits and vegetables.

Consequences of obesity • Increase in morbidity & mortality rates. • Reduced longevity in next few decades • Increased risk and duration of lifetime disability. • Obesity in middle age group is associated with poor indices of quality of life at old age. Ref: Insurance databases & large cohort studies from the Framingham and NHANES studies (USA)

Obese Syndrome Components Glucose intolerance Insulin resistance Dyslipidemia Type 2 diabetes Hypertenision Elevated plasma leptin concentration • Increased visceral adipose tissue • Increased risk of CHD & some cancers • • •

Factors associated with obesity modulate morbidity and mortality • • Age of onset of obesity Duration of obesity, Severity of obesity, Amount of central adiposity, Other co-morbidities, Gender Level of cardio-respiratory fitness.

Weight Loss Therapy is Recommended • With BMI ≥ 23 • Waist measurement of: ≥ 90 cm for men and ≥ 80 cm for women • Two or more risk factors 43

Approach to Obesity at Clinical level • A full history with a dietary inventory and an analysis of the subject's activity level. • Screening questions to exclude depression • Screening for eating disorders as 30% of patients suffer from them • Determine any co-morbidities; • Exclude the possible and rare secondary causes • Requirements of treatment and belief to fulfill • Behavior assessment for readiness • Family support, time and financial considerations

Approach at community level Empowering parents, and caregivers Healthy foods in schools & restaurants Access to healthy affordable food Avenues for physical activity (www. letsmove. gov) Safe neighborhoods; playgrounds, parks Physical education in schools/child care facilities Encourage breast feeding Farmers markets; local fruits and vegetables available • Any barriers considered • •

Keeping a watch on public messages

Grains, Vegetables, Fruits, Milk/Dairy, Meat & Beans & oils

Steps to follow at individual level • • • Cutting Back on Salt and Sodium Be a Healthy Role Model for Children Following a Vegetarian Diet Going Green with My Pyramid Choose a Harvest of Colorful Vegetables Make Half Your Grains Whole Focus on Fruits Cut Back on Sweet Treats Brisk walk 3 times/day for 10 minutes ; 5 days/wk

Conclusion • Obesity is a substantial public-health crisis • The prevalence is increasing rapidly in numerous developing nations worldwide; including Saudi Arabia • This growing rate represents a pandemic that needs urgent attention; potential for morbidity, mortality, and economic tolls.