1. الجامعة السورية الخاصة كلية الطب البشري قسم طب المجتمع
Obesity
M.A.Kubtan MD - FRCS
M.A.Kubtan

2. Key Points
Body mass index (BMI) determines the classification of obesity for clinical use.
Waist circumference reflects the distribution of adipose tissue and helps determine obesity risk.
Central obesity, reflected by a high waist measurement, is associated with more complications.
M.A.Kubtan

3. Demographics Gender Differences Race and Ethnic Origin   
Gender Differences  
Race and Ethnic Origin  
Socioeconomic Status  
Education Level  
Rural and Urban Differences  
Age 
M.A.Kubtan

4. Determinants of Obesity
Genetics vs. Lifestyle 
Lifestyle Influences 
Endocrine and Metabolic Factors 
M.A.Kubtan

5. Body mass index (BMI) Body mass index can be calculated as :
wt (kg)/ht2 (m) .
M.A.Kubtan

6. The problem of obesity
Globally, overnutrition has now surpassed undernutrition as a public health concern
8.5% of the world population is overweight
5.8% underweight
2.3 billion adults will be overweight and 700,000 million obese by 2015.
Persons in the overweight category have 20% to 40% increased mortality,
M.A.Kubtan

7. Continue
Workers with BMI over 35 kg/m2 experienced a 4.2% health-related drop in productivity
The medical consequences of obesity have been estimated to account for 9.1% of annual medical spending .
M.A.Kubtan

8. M.A.Kubtan

9. M.A.Kubtan

10. Surveys from 1976–1980 and 2003–2006 found that :
Obesity increased from 5.0% to 12.4% among children age 2 to 5 years;
From 6.5% to 17.0% for ages 6 to 11 years;
From 5.0% to 17.6% for ages 12 to 19 years. Changes in obesity prevalence have affected all U.S. regions
M.A.Kubtan

11. Assessment
BMI .
Body fat percentage : is a precise assessment of adiposity
M.A.Kubtan

12. Health risks increase above a waist circumference of 35 inches in women and 40 inches in men
M.A.Kubtan

13. Demographics Men are more likely than women to have central obesity.
African Americans, Hispanics, and Native Americans are at greater risk of obesity than whites.
Obesity is inversely related to education and socioeconomic status.
Obesity is more prevalent in rural than urban areas.
M.A.Kubtan

14. Gender Differences Men are more likely than women to be overweight .
Women are more likely to be obese.
Men, however, are more likely to have central obesity, associated with greater health risks.
M.A.Kubtan

15. Socioeconomic Status
The prevalence ranges from approximately 2% in the least developed countries to over 30% in the most developed countries.
In developed countries, lower socioeconomic status is associated with an increased risk.
M.A.Kubtan

16. Education Level
Education level is inversely related to the risk of obesity .
M.A.Kubtan

17. Rural and Urban Differences
Analysis data shows that the prevalence of obesity is greater in rural than urban areas.
Factors that reduce physical activity may play a role .
M.A.Kubtan

18. Age
The increased prevalence of overweight is alarming in the pediatric population .
More than 30% of children and adolescents are overweight or obese.
M.A.Kubtan

19. Determinants of Obesity Genetic Factors
Obesity results from the interaction of genetic makeup, environment, and lifestyle.
Genetic factors are estimated to account for 30% to 40% of the variability in adult weight.
Overall, genetic factors are estimated to be responsible for 30% to 40% of the variability in adult weight.
Specific metabolic or endocrine disorders account for less than 1% of the obese population.
M.A.Kubtan

20. Determinants of Obesity Modern Life Factors
Obesity results from calorie consumption in excess of expenditure.
The conveniences of modern life have led to a decrease in energy expenditure.
A greater access to energy-dense food, along with other factors, has increased energy consumption.
M.A.Kubtan

21. Lifestyle Influences
Increased caloric intake is related in part to eating away from home.
Smoking cessation is associated with weight gain of 4 to 5 kg (on average).
Many antidepressants, neuroleptics, and anticonvulsants are associated with weight gain.
Decreased overall physical activity (not just “exercise”) is a major factor associated with the increasing prevalence of overweight and obesity.
M.A.Kubtan

22. Impact of Genetic Factors
More than 250 genes and chromosomal regions are associated with phenotypic obesity .
The genes code specifically for visceral as opposed to subcutaneous obesity.
M.A.Kubtan

23. Humeral Factors affecting Obesity
Leptin is a protein produced in adipose tissue that provides negative feedback to appetite control centers.
Ghrelin, a peptide produced in the stomach and duodenum that stimulates eating.
Defects in melanocortin receptors in the adrenals have also been associated with obesity.
FTO (fat mass and obesity-associated) gene .
M.A.Kubtan

24. Probable role of Melanocortin
Melanocortin 4 receptor (MC4R) deficiency is the commonest monogenic form of obesity. However, the clinical spectrum and mode of inheritance have not been defined, pathophysiological mechanisms leading to obesity are poorly understood, and there is little information regarding genotype- phenotype correlations
M.A.Kubtan

25. Modulation of Appetite
Leptin levels.
Vagal afferent activity .
Fluctuation in plasma glucose levels.
Neuropeptides and monoamine neurotransmitters are also involved in appetite control.
Some weight loss medications may affect appetite or satiety.
M.A.Kubtan

26. Endocrine and Metabolic Factors
Hypothyroidism is a relatively rare cause of obesity.
Neuroendocrine Factors
Cushing’s Syndrome is associated with central obesity and “buffalo hump” along with axillary striae, glucose intolerance and hypertension.
Polycystic Ovary Syndrome , menstrual irregularities , hirsutism, elevated testosterone and luteinizing hormone blood levels , Insulin resistance is a consistent finding .
Growth Hormone Deficiency , impaired in growth hormone deficiency, there is an increase in truncal obesity.
M.A.Kubtan