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Chapter 09

Chapter 09. Physical Activity and Obesity. Physical Activity and Obesity. Definitions: Obesity: Having a very high amount of body fat in relation to lean body mass, or Body Mass Index (BMI) of 30 or higher.

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Chapter 09

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  1. Chapter 09 Physical Activity and Obesity

  2. Physical Activity and Obesity • Definitions: • Obesity: Having a very high amount of body fat in relation to lean body mass, or Body Mass Index (BMI) of 30 or higher. • Body Mass Index (BMI): A measure of an adult’s weight in relation to his or her height, specifically the adult’s weight in kilograms divided by the square of his or her height in meters. Source = CDC Physical Activity and Obesity

  3. Obesity Trends Among U.S. Adults between 1985 and 2010 • Source of the data: • The data shown in these maps were collected through CDC’s Behavioral Risk Factor Surveillance System (BRFSS). Each year, state health departments use standard procedures to collect data through a series of monthly telephone interviews with U.S. adults. • Prevalence estimates generated for the maps may vary slightly from those generated for the states by BRFSS as slightly different analytic methods are used. Source = CDC Physical Activity and Obesity

  4. Obesity Trends Among U.S. Adults between 1985 and 2006 • In 1990, among states participating in the Behavioral Risk Factor Surveillance System, 10 states had a prevalence of obesity less than 10% and no states had prevalence equal to or greater than 15%. • By 1998, no state had prevalence less than 10%, seven states had a prevalence of obesity between 20-24%, and no state had prevalence equal to or greater than 25%. • In 2006, only four states had a prevalence of obesity less than 20%. Twenty-two states had a prevalence equal or greater than 25%; Two of these states (Mississippi and West Virginia) had a prevalence of obesity equal to or greater than 30%. • In 2009–2010, 35.7% of U.S. adults were obese. Source = CDC Physical Activity and Obesity

  5. Obesity Trends* Among U.S. AdultsBRFSS,1990, 1998, 2006, 2010 (*BMI 30, or about 30 lbs. overweight for 5’4” person) 1998 1990 2006 No Data <10% 10%–14% 15%–19% 20%–24% 25%–29% ≥30% Physical Activity and Obesity

  6. Obesity Trends* Among U.S. AdultsBRFSS, 1985 (*BMI ≥30, or ~ 30 lbs. overweight for 5’ 4” person) No Data <10% 10%–14% Physical Activity and Obesity

  7. Obesity Trends* Among U.S. AdultsBRFSS, 1988 (*BMI ≥30, or ~ 30 lbs. overweight for 5’ 4” person) No Data <10% 10%–14% Physical Activity and Obesity

  8. Obesity Trends* Among U.S. AdultsBRFSS, 1991 (*BMI ≥30, or ~ 30 lbs. overweight for 5’ 4” person) No Data <10% 10%–14% 15%–19% Physical Activity and Obesity

  9. Obesity Trends* Among U.S. AdultsBRFSS, 1994 (*BMI ≥30, or ~ 30 lbs. overweight for 5’ 4” person) No Data <10% 10%–14% 15%–19% Physical Activity and Obesity

  10. Obesity Trends* Among U.S. AdultsBRFSS, 1998 (*BMI ≥30, or ~ 30 lbs. overweight for 5’ 4” person) No Data <10% 10%–14% 15%–19% ≥20% Physical Activity and Obesity

  11. Obesity Trends* Among U.S. AdultsBRFSS, 2002 (*BMI ≥30, or ~ 30 lbs. overweight for 5’ 4” person) No Data <10% 10%–14% 15%–19% 20%–24% ≥25% Physical Activity and Obesity

  12. Obesity Trends* Among U.S. AdultsBRFSS, 2004 (*BMI ≥30, or ~ 30 lbs. overweight for 5’ 4” person) No Data <10% 10%–14% 15%–19% 20%–24% ≥25% Physical Activity and Obesity

  13. Obesity Trends* Among U.S. AdultsBRFSS, 2006 (*BMI ≥30, or ~ 30 lbs. overweight for 5’ 4” person) No Data <10% 10%–14% 15%–19% 20%–24% 25%–29% ≥30% Physical Activity and Obesity

  14. Obesity Trends* Among U.S. AdultsBRFSS, 2008 (*BMI ≥30, or ~ 30 lbs. overweight for 5’ 4” person) No Data <10% 10%–14% 15%–19% 20%–24% 25%–29% ≥30%

  15. Obesity Trends* Among U.S. AdultsBRFSS, 2010 (*BMI ≥30, or ~ 30 lbs. overweight for 5’ 4” person) No Data <10% 10%–14% 15%–19% 20%–24% 25%–29% ≥30%

  16. Obesity Trends Among U.S. Adults Physical Activity and Obesity

  17. Childhood Overweight • BMI is used to Screen for Overweight in Children • For children and adolescents (aged 2–19 years), the result is plotted on the CDC growth charts to determine the corresponding BMI-for-age percentile. Overweight is defined as a BMI at or above the 95th percentile for children of the same age and sex. This definition is based on the 2000 CDC Growth Charts for the United States. A child’s weight status is determined based on an age- and sex-specific percentile for BMI rather than by the BMI categories used for adults. Classifications of overweight for children and adolescents are age- and sex-specific because children’s body composition varies as they age and varies between boys and girls. Source = CDC Physical Activity and Obesity

  18. Trends in Childhood Overweight Prevalence of Overweight* Among U.S. Children and Adolescents(Aged 2 –19 Years)National Health and Nutrition Examination Surveys Physical Activity and Obesity

  19. Trends in Childhood Overweight Physical Activity and Obesity

  20. Trends in Childhood Overweight Physical Activity and Obesity

  21. Trend Summary (2012) Physical Activity and Obesity

  22. Consequences of Childhood Overweight • Psychosocial Risks • Some consequences of childhood and adolescent overweight are psychosocial. Overweight children and adolescents are targets of early and systematic social discrimination. The psychological stress of social stigmatization can cause low self-esteem which, in turn, can hinder academic and social functioning, and persist into adulthood Source = CDC Physical Activity and Obesity

  23. Consequences of Childhood Overweight • Cardiovascular Disease Risks • Overweight children and teens have been found to have risk factors for cardiovascular disease (CVD), including high cholesterol levels, high blood pressure, and abnormal glucose tolerance. In a population-based sample of 5- to 17-year-olds, almost 60% of overweight children had at least one CVD risk factor while 25 percent of overweight children had two or more CVD risk factors. Source = CDC Physical Activity and Obesity

  24. Consequences of Childhood Overweight • Additional Health Risks • Less common health conditions associated with increased weight include asthma, hepatic steatosis, sleep apnea and Type 2 diabetes. • Asthma is a disease of the lungs in which the airways become blocked or narrowed causing breathing difficulty. Studies have identified an association between childhood overweight and asthma. • Hepatic steatosis is the fatty degeneration of the liver caused by a high concentration of liver enzymes. Weight reduction causes liver enzymes to normalize. Source = CDC Physical Activity and Obesity

  25. Consequences of Childhood Overweight • Additional Health Risks • Sleep apnea is a less common complication of overweight for children and adolescents. Sleep apnea is a sleep-associated breathing disorder defined as the cessation of breathing during sleep that lasts for at least 10 seconds. Sleep apnea is characterized by loud snoring and labored breathing. During sleep apnea, oxygen levels in the blood can fall dramatically. One study estimated that sleep apnea occurs in about 7% of overweight children. • Type 2 diabetes is increasingly being reported among children and adolescents who are overweight. While diabetes and glucose intolerance, a precursor of diabetes, are common health effects of adult obesity, only in recent years has Type 2 diabetes begun to emerge as a health-related problem among children and adolescents. Onset of diabetes in children and adolescents can result in advanced complications such as CVD and kidney failure. Source = CDC Physical Activity and Obesity

  26. How to break the cycle?

  27. Treating Childhood Obesity • Change family lifestyle. • Parents should be “agents of change” for young children. • Use behavior modification to support long-term change in behavior, including modifying the environment (e.g., removing cues to eat and adding cues to be active), monitoring behavior, setting and checking goals, and rewarding positive change.

  28. Treating Childhood Obesity • A review that compared lifestyle and drug treatments for obesity in children and adolescents found that 12 interventions, centered on increasing physical activity or reducing sedentary behaviors, had on average a significant effect on reducing BMI after six or 12 months. The effect was small compared to treatment with the drugs orlistat or sibutramine,(withdrawn from market) but the drugs had adverse side effects in the children

  29. Treating Childhood Obesity • Increase physical activity: have children do more unstructured outdoor play; have them use active transport (e.g., walking or bicycling) to school and parks; provide transportation for sport participation when needed; parents should model an active lifestyle. • Use nonconventional treatments, including weight loss drugs, as an adjuvant to support long-term lifestyle changes in adolescents who are obese.

  30. Treating Childhood Obesity • Change dietary intake and eating patterns: parents should model healthy food choices and have children eat lower-fat and lower-energy foods, increase fruits and vegetables, decrease portion sizes, and drink fewer sweetened beverages. • Decrease time spent in sedentary behavior (e.g., limit television viewing and computer use to less than 2 h each day).

  31. Consequences of Obesity In Adults • Overweight and obese individuals are at increased risk for many diseases and health conditions, including the following: • Hypertension (high blood pressure) • Osteoarthritis (a degeneration of cartilage and its underlying bone within a joint) • Dyslipidemia (for example, high total cholesterol or high levels of triglycerides) • Type 2 diabetes • Coronary heart disease • Stroke • Gallbladder disease • Sleep apnea and respiratory problems • Some cancers (endometrial, breast, and colon) Source = CDC Physical Activity and Obesity

  32. Economic Burden of Obesity • Article on the economic impact (burden) of obesity on The United States Obesity cost the United States an estimated $147 billion in 2008, nearly 10% of all medical costs (Finkelstein et al. 2009). In a simulation model of population data, medical costs of obesity were higher than for smoking until people reached their mid 50s, after which smokers had higher costs. However, lifetime costs were still higher in people who were obese because smokers died at younger ages Physical Activity and Obesity

  33. Treatment of Obesity • The NIH expert panel on obesity and overweight (National Heart, Lung, and Blood Institute 1998) reached these conclusions, though updates are expected in the near future: • Physical activity is a clinically accepted approach to weight loss, as are low-calorie diets and lower-fat diets, behavior therapy, pharmacotherapy, surgery, and combinations of these techniques. • For most overweight people, the initial goal of a prudent weight loss program is to lose about 10% of weight over a period of six months. • After six months, the rate of weight loss usually declines, and weight tends to stabilize at a plateau because of the reduction in basal metabolic rate that results from the lower body mass • Lost weight is usually regained unless a weight maintenance program consisting of dietary therapy, physical activity, and behavior therapy is continued indefinitely. After six months of successful weight loss, efforts to maintain weight loss should be undertaken.

  34. Assessing and Defining Overweight and Obesity • Quetelet’s body mass index (BMI) and relative weight are typically used to estimate overweight and obesity in epidemiologic studies because they are easy to assess in large numbers of subjects.

  35. Patterning of Body Fat and Disease Risk • Excess fat in the abdomen out of proportion to total body fat is another risk factor for chronic diseases associated with obesity. • The waist-to-hip ratio predicts the patterning of visceral fat. Excess fat above the waist, so-called android fat, increases risk for CHD more than does excess fat below the waist, so-called gynoid fat. The American Heart Association (2001) suggests that the desirable waist-to-hip ratio is less than 1.00 for men and less than 0.80 for women. • Table 9.3 (next slide) illustrates the additive risk of increased abdominal fat to the risk of BMI in the development of obesity-associated diseases in adults with a BMI of 25 to 34.9 kg/m2. Waist circumference does not add to the accuracy of predicting disease risk in people who have a BMI of 35 kg/m2 or more.

  36. Patterning of Body Fat and Disease Risk

  37. The Consensus About Obesity • In 1995, the National Heart, Lung, and Blood Institute’s Obesity Education Initiative and the National Institute of Diabetes and Digestive and Kidney Diseases assembled an expert panel charged with the identification, evaluation, and treatment of overweight and obesity in adults. Their guidelines (based on 236 clinical studies), which appeared in 1998 are as follows: • Treatment of overweight is recommended only when patients have two or more risk factors or a high waist circumference. Treatment should focus on altering dietary and physical activity patterns to prevent development of obesity and to produce moderate weight loss. Physical Activity and Obesity

  38. The Consensus About Obesity • Cardiovascular risk factors among obese people do not differ from those for people of normal weight. • Obese people who have at least three major CHD risk factors usually require medical treatment aimed at risk reduction. Their CHD risk is increased further if they are physically inactive and have high serum triglycerides (>200 mg/dl), though the increased risk has not been quantified. • There is strong evidence that weight loss among people who are overweight or obese reduces risk factors for diabetes and cardiovascular disease (CVD). Weight loss reduces blood pressure in both hypertensive and non hypertensive overweight individuals, reduces serum triglycerides, increases HDL-C, and somewhat reduces total serum cholesterol and low density lipoprotein cholesterol (LDL-C). Weight loss reduces blood glucose levels in overweight and obese people with and without diabetes and can reduce glycosylated hemoglobin (HbA1c) in people with type 2 diabetes.

  39. Metabolic Syndrome • The American Heart Association and the National Heart, Lung, and Blood Institute recommend that the metabolic syndrome be identified as the presence of three or more of these components (specific to population; U.S. shown): •Elevated waist circumference: Men—equal to or greater than 40 in. (102 cm) Women—equal to or greater than 35 in. (88 cm) •Elevated triglycerides: Equal to or greater than 150 mg/dl Physical Activity and Obesity

  40. Metabolic Syndrome •Reduced HDL (“good”) cholesterol: Men—less than 40 mg/dl Women—less than 50 mg/dl •Elevated blood pressure: Equal to or greater than 130/85 mmHg •Elevated fasting glucose: Equal to or greater than 100 mg/dl Obesity is considered a disease, there is controversy about whether it is an independent cause of premature death or whether it is deadly because of the constellation of risk factors for mortality that accompanies obesity (Metabolic Syndrome)

  41. Etiology of Overweight and Obesity: Set Point or settling Point? • Two common theories about the etiology of overweight and obesity, set point and settling point, address how physical activity can play a role in the treatment or prevention of overweight and obesity. Physical Activity and Obesity

  42. Set Point Theory • Set point theory hypothesizes that the body has an internal control mechanism, that is, a set point, located in the lateral hypothalamus of the brain, that regulates metabolism to maintain a certain level of body fat. • Though evidence in rats has supported the theory, there is no scientific consensus that such a metabolic set point exists in humans for fat maintenance. Physical Activity and Obesity

  43. SettlingPoint Theory • Weight loss and gain in most humans are more related to the patterns of diet and physical activity that people “settle” into as habits based on the interaction of their genetic dispositions, learning, and environmental cues to behavior. • Evidence suggests that obese people are more sensitive to food-related stimuli in the social and physical environment, which influence their energy intake, than to the stimuli for energy expenditure Physical Activity and Obesity

  44. The Role of Physical Activity • Physical activity has an important role in the prevention and treatment of overweight and obesity, even if that role is not yet completely understood. • Prevention of obesity in children should focus on increasing vigorous physical activity rather than restricting energy intake • Evidence shows that regular physical activity or physical fitness can (1) reduce health risks in people who are overweight, (2) protect against excessive weight gain, (3) help overweight and obese people lose weight, and (4) help people maintain stable weight after they lose it. Physical Activity and Obesity

  45. Physical Activity and Fitness and the Health Risks of Obesity: The Evidence • Physical Activity Studies on the joint association of self-reported physical activity and high BMI typically show that each is an independent risk factor for all-cause mortality and mortality from CVD and cancer. • The mortality risk of obesity is not eliminated by physical activity, but it was usually reduced substantially in population cohorts that did not initially have a chronic disease. Physical Activity and Obesity

  46. Physical Activity and Overweight or Obesity: The Evidence Physical Fitness • Lipid Research Clinics Mortality Study • examined the prospective associations of fitness and BMI with mortality risk in 1359 Russian men and 1716 U.S. men aged 40 to 59 years who were followed for 18 to 23 years • fitness eliminated the risks of obesity in Russian men; but in American men, fitness and fatness were associated with mortality independently of each other Physical Activity and Obesity

  47. Physical Activity and Overweight or Obesity: The Evidence Physical Fitness • Aerobics Center Longitudinal Study • Association of fitness with reduced risk of CVD and all-cause mortality was independent of overweight • When all other variables were accounted for, fitness level was the determining factor for relative risk. BMI variance in each fitness category did not change the relative risk (see Figure 9.8, next slide) Physical Activity and Obesity

  48. Figure 9.8 - Aerobics Center Longitudinal Study with 21,856 men followed for approximately eight years. a total of 21,925 men aged 33 to 83 years were followed and men with abnormal ECG or history of myocardial infarction, stroke, or cancer excluded. results were adjusted for age, examination year, smoking, alcohol intake, and parental history of coronary heart disease

  49. Physical Activity and Overweight or Obesity: The Evidence Physical Fitness • Women’s Ischemia Syndrome Evaluation (WISE) • From 1996 to 2000, 936 women were enrolled at four U.S. academic medical centers when clinical evaluation and angiography indicated they had myocardial ischemia At enrollment, 76% were overweight. • Overweight women were more likely than normal weight women to have CAD risk factors, but BMI and girth measures were not associated with CAD or cardiovascular events after adjustment for other risk factors. Lower fitness scores at entry were 80% more likely to have CAD risk factors Physical Activity and Obesity

  50. Physical Activity and Overweight or Obesity: The Evidence Fit But Fat ? A recent large study using pooled data from 19 prospective studies of 1.46 million white adults, 19 to 84 years of age, observed that after taking biases from smoking and ill health into consideration and adjusting for physical activity, there was a J-shaped relationship between BMI and all-cause mortality (Berrington de Gonzalez et al. 2010). The highest mortality rates occurred at BMI of 40.0 to 49.9 kg/m2 and the lowest generally at 20.0 to 24.9 kg/m2. The evidence is clear that physical activity can favorably modify the impact of overweight and moderate obesity on several health risk factors, including metabolic syndrome

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