The crucial role of physical activity in the prevention and management of overweight and obesity Dunedin, New Zealand Fe

1. The crucial role of physical activity in the prevention and management of overweight and obesityDunedin, New ZealandFebruary 1, 2010 Steven N. Blair sblair@mailbox.sc.edu Departments of Exercise Science & Epidemiology/Biostatistics University of South Carolina

2. Physical Environment • Eating on the run Calorie-dense foods Larger portions Building design Urban sprawl Lactation • Powerful and constant advertising Absence of sidewalks More sedentarism Pollutants Certain medications • Pressure to consume High fat diets • Eating as recreation Maternal-fetal nutrition Population density Automobile dependency Energy Intake Nutrient / Energy Partitioning • Pressure to be sedentary Social Environment Obesity Genetic Predisposition • Society of spectators instead of participant Behavior Corn fructose syrup Less physical activity Smoking cessation Overweight • Fewer meals at home Energy Expenditure Adipogenesis n-6/n-3 PUFAs Thermogenesis CNS regulators of appetite: NPY, a-MSH, CART, Orexins, Agouti, MC4R, MCH, AGRP, etc. Lipid ox Viruses RMR Regulators of adipogenesis: RAR, RXR, PPARg, C/EBP, SREBP-1c, PGC-1, etc. Peripheral regulators of appetite: PYY, insulin, leptin, ghrelin, CCK, GLP-1, etc. Biology Genetic hypotheses Epigenetics

3. Overview of Lecture • Crucial role of physical activity and fitness to health outcome • Physical activity and weight management • Physical activity and prevention of weight gain • Physical activity and weight loss • Physical activity and the prevention of weight regain

4. Leading Causes of Death in the World WHO. Global Health Risks. 2009.

5. Aerobics Center Longitudinal Study

6. Design of the ACLS 1970 More than 80,000 patients 2005 Cooper Clinic examinations--including history and physical exam, clinical tests, body composition, EBT, and CRF Mortality surveillance to 2003 More than 4000 deaths 1982 ‘86 ‘90 ‘95 ’99 ‘04 Mail-back surveys for case finding and monitoring habits and other characteristics

7. All-Cause Death Rates by CRF Categories—3120 Women and 10 224 Men—ACLS Blair SN. JAMA 1989

8. Amount of Specific Physical Activities for Moderately Fit Women and Men • Detailed physical activity assessments in women and men who also completed a maximal exercise test • Average min/week for the moderately fit who only reported each specific activity Mean Min/week N=3,972 13,444 Stofan JR et al. AJPH 1998; 88:1807

9. Death Rates and RR for Selected Mortality Predictors, Men, ACLS Death rates and relative risks are adjusted for age and examination year Relative risks are for risk categories shown here compared with those not at risk on that predictor Blair SN et al. JAMA 1996; 276:205-10

10. Death Rates and RR for Selected Mortality Predictors, Women, ACLS Death rates and relative risks are adjusted for age and examination year Relative risks are for risk categories shown here compared with those not at risk on that predictor Blair SN et al. JAMA 1996; 276:205-10

11. Cardiorespiratory Fitness, Risk Factors and All-Cause Mortality, Men, ACLS # of risk factors Risk Factors current smoking SBP >140 mmHg Chol >240 mg/dl Cardiorespiratory Fitness Groups *Adjusted for age, exam year, and other risk factors Blair SN et al. JAMA 1996; 276:205-10

12. CRF and Digestive System Cancer Mortality 38,801 men, ages 20-88 years 283 digestive system cancer deaths in 17 years of follow-up CRF was inversely associated with death after adjustment for age, examination year, body mass index, smoking, drinking, family history of cancer, personal history of diabetes Fit men had lower risk of colon, colorectal, and liver cancer deaths High Fit Moderately Fit Low Fit Peel JB et al. Cancer Epidemiol Biomarkers Prev 2009; 18:1111

13. CRF and Breast Cancer Mortality Odds Ratio 14,551 women, ages 20-83 years Completed exam 1970-2001 Followed for breast cancer mortality to 12/31/2003 68 breast cancer deaths in average follow-up of 16 years Odds ration adjusted for age, BMI, smoking, alcohol intake, abnormal ECT, health status, family history, & hormone use p for trend=0.04 Sui X et al. MSSE 2009; 41:742

14. Age, examination year adjusted metabolic syndrome incidence rates by cardiorespiratory fitness in 10,221 men from ACLS 1977-2005 P trend < 0.0001 Maximal METs

15. Activity, Fitness, and Mortality in Older Adults

16. Cardiorespiratory Fitness and All-Cause Mortality, Women and Men ≥60 Years of Age All-Cause death rates/1,000 PY • 4060 women and men ≤60 years • 989 died during ~14 years of follow-up • ~25% were women • Death rates adjusted for age, sex, and exam year Age Groups Sui M et al. JAGS 2007.

17. We will all die eventually, but Who wants to spend their last years in a nursing home?

18. Fitness and Functional Limitations, Women and Men, ACLS • Risk of self-reported functional limitation adjusted for age, follow-up, BMI, smoking, alcohol intake, baseline disease, & disease at follow-up Huang et al. MSSE 1998, 30:1430-5

19. Cardiorespiratory Fitness and Risk of Dementia, ACLS Hazard Ratio • 59,960 women and men • Followed for 16.9 years after clinic exam • 4,108 individuals died • 161 with dementia listed on the death certificate • Hazard ratio adjusted for age, sex, exam yr, BMI, smoking, alcohol, abnormal ECG, history of hypertension, diabetes, abnormal lipids, and health status P for trend=0.002 Fitness Categories Lui R et al. In review

20. Exercise Is Medicine

21. Physical Activity as Treatment for Chronic Disease

22. Age and exam year adjusted rates of total CVD events by levels of CRF and severity of HTN in 8147 hypertensive men CVD incidence/1000 man-years P <.001 P <.001 P =.048 CRF: Controlled HTN Stage 1 HTN Stage 2 HTN Severity of HTN Sui X et al. Am J Hyptertension. 2007

23. Physical Activity and Survival2987 Women with Breast Cancer Nurses’ Health Study Multivariable adjusted relative risk Similar findings for breast cancer recurrance Physical Activity in MET-hours/Week Holmes MD et al. JAMA 2005; 293:2479

24. Yes, But Those Are Observational Studies, and We Require Randomized Clinical Trial Evidence

25. Exercise Is As Good As Other Treatments for Clinical Depression % of Patients with Remission of Depression Amount of Brisk Walking Drug therapy and cognitive behavioral therapy produce remission in approximately 40% of clinically depressed individuals Dunn A et al. Am J Prev Med 2005

26. Exercise Training and Angioplasty, 101 Men with Stable CAD Event-free survival (%) Per unit change in angina-CCS Exercise was 20 minutes/day on a cycle ergometer Hambrecht R et al. Circulation 2004; 109:1371

27. Reduction in Risk of Developing Diabetes in Comparison with Controls, DPP 100 *Moderate intensity exercise of 150 min/week; low calorie, low fat diet 80 58% 60 Risk reduction (%) 40 31% 20 0 Lifestyle Intervention* Metformin DPP Research Group. NEJM 2002; 346:393-403

28. Cost Effectiveness of Diabetes Prevention-DPP • The lifestyle and metformin groups cost $2,250 more/year than placebo • As implemented in the DPP and from a societal perspective, lifestyle was more cost effective than metformin DPP Res Group. Diab Care 2003; 26:2518

29. Do We Have an Obesity Epidemic? • Yes, and I am not going to show you the obesity maps to prove it! • What is the cause of the obesity epidemic? • No one knows, other than there have been too many people in a positive caloric balance on too many days • But there is a lot of passion on the topic

30. It’s calories that count Energy Out Energy In Portion size High-fat foods Energy dense Low-fiber Soft drinks Media (TV,PC) Cars No heavy labour

31. However, Energy Balance Is Poorly Understood

32. Donald Kennedy & Philip Abelson. The Obesity Epidemic. Science 2004; 304:1413 • “…Americans continued to consume an average of 3800 calories per person per day, or about twice the daily requirement.”

33. What Is Wrong with the Statement? • “…Americans continued to consume an average of 3800 calories per person per day, or about twice the daily requirement.” • 3800/2=1900 extra calories/day • ~7700 calories to lay down 1 kg of fat • ~1 kg every 4 days • ~90 kg/year Kennedy & Abelson. The Obesity Epidemic. Science 2004; 304:1413

34. Cause(s) of the Obesity Epidemic • Increases in energy intake • Decreases in energy expenditure • Changes in specific micro or macronutrients • Combination of increases in intake and decreases in expenditure • 50/50? • 30/70? • 70/30?

35. Hypothetical Model for the Cause of the Obesity Epidemic of the Late 20th Century Energy balance Energy balance Energy intake Kcal Energy expenditure 1900 1950 2000

36. Is the Average Total Daily Caloric Intake Increasing?

37. Trends in Energy IntakeNHANES 1971-2000 • Data sources • NHANES I—1971-1974 • NHANES II—1976-1980 • NHANES III—1988-1994 • NHANES—1999-2000 • Surveys were representative samples of noninstitutionalized U.S. women and men aged 20 to 74 years Source: MMWR Feb 6, 2004

38. Trends in Energy Intake1971 to 2000, Men, NHANES Kcal/day Source: MMWR Feb 6, 2004

39. Trends in Energy Intake1971 to 2000, Women, NHANES Kcal/day Source: MMWR Feb 6, 2004

40. NHANES Survey Methods 1971-2000 • NHANES I and NHANES II • 24-hour dietary recall, Monday-Friday • NHANES III and NHANES • 24-hour dietary recall, Monday-Sunday • Other changes in methodology included better probing techniques and better training of interviewers • Other changes in dietary behavior included more meals eaten away from home and increasing portion sizes

41. Physical Activity or Total Energy Expenditure? • Physical activity assessments in free-living individuals are problematic and often lead to substantial misclassification (although these problems are at least as common for dietary assessment) • Most epidemiological studies have assessed physical activity habits by self-reported questionnaires • Physical activity reports are not the same as energy expenditure

42. BRFSS Trend Data, Women and Men

43. Hypothesis Regarding Energy Intake, Expenditure, and Balance Energy balance Normal distribution of susceptibility to dysregulation kcal intake kcal expenditure Jim Hill & Russ Pate contributed to the concept

44. How Much Physical Activity Is Required? • To prevent initial weight gain • To lose weight • To prevent weight regain • No One Knows! • However, many people think they know

45. Prevention of Unhealthful Weight Gain: What Is Required? • ACSM/CDC recommendation—30 min of moderate intensity on most days • IOM recommendation—60 min per day • WHO recommendation—“In order to avoid obesity, populations should remain physically active throughout life at a PAL of 1.75 or more”

46. Physical Activity Level (PAL) • Expresses daily energy expenditure as multiples of BMR average over 24 hours • How high should PAL be in order to prevent unhealthful weight gain? • PAL categories • Sedentary—1.4 • Limited activity—1.55-1.60 • Physically active--1.75 WHO Consultation on Obesity 1998

47. Energy Requirement for Subsistence Farming Total energy expenditure (PAL)=1.78 FAO/WHO Joint Consultation. Energy & Protein Requirements. WHO Technical Report Series #724

48. Is a PAL of 1.75 or the IOM 60 Minutes/Day Required to Prevent Weight Gain? • Prevalence of obesity in U.S. adults was constant 10% for several decades prior to 1985 • Prevalence has increased rapidly to one third at present • If a PAL of 1.75 is required to prevent unhealthful weight gain, 90% of U.S. adults must have had a PAL of 1.75 prior to 1985 • Does this assumption seem likely?

49. Dietary Guidelines for Americans 2005*Physical activity recommendations • To help manage body weight and prevent gradual, unhealthy body weight gain in adulthood: Engage in approximately 60 minutes of moderate- to vigorous-intensity activity on most days of the week while not exceeding caloric intake requirements *www.health.gov/dietaryguidelines/dga2005/document/

50. Prevention of Weight Gain with Physical ActivityObservational Studies