1. The Role of Physical Activity in the Prevention and Treatment of Obesity Origins of Obesity—2011 Symposium Iowa State University May 9, 2011
Steven N. Blair
Departments of Exercise Science & Epidemiology/Biostatistics
University of South Carolina

2. Disclosures Medical/Scientific Advisory Boards Research Funding
Jenny Craig, Inc
Alere
Technogym
Cancer Foundation for Life
Santech
Clarity Project
Research Funding
NIH
Body Media
Coca Cola
Department of Defense

3. Acknowledgements Co-investigators Post-doctoral scholars PhD students
Xuemei Sui
Tim Church
James Hebert
Greg Hand
Ian Janssen
Francisco Ortega
Jonatan Ruiz
Steve Hooker
Michael Beets
Sara Wilcox
Chris Riddoch
Andrew Jackson
Paul McAuley
Susumu Sawada
Andy Ness
Post-doctoral scholars
D.C. Lee
Meghan Baruth
Jongkyu Kim
Enrique Artero
PhD students
Amanda Paluch
John Sieverdes
Vaughn Barry
Jonathan Mitchell
Won Byun
Tatiana Warren
Andrea Maslow
Will Lyerly
Ed Archer

4. Do We Have an Epidemic of Obesity?

5. Global Trends in Adult Obesity
Reference: International Obesity Taskforce. Trends in Adult Obesity Prevalence in Europe. Available at: Accessed 23 March 2010.
International Obesity Taskforce.

6. Do we know how to prevent obesity?
Yes!!!!!
Sit less and stand more

7. How to Stand
Detailed instructions from the Department of Health and Human Services

9. Introducing “Exertol” Your Physical Activity Prescription

11. Which causes more deaths in the U.S.—smoking or obesity?
~40% of U.S. adults think obesity causes at least as many deaths as does smoking
~20% of U.S. adults think obesity causes more deaths than smoking
The truth
Smoking causes ~440,000 deaths/year
Obesity causes ~110,000 deaths/year
Uncritical, Unfounded, or Unusual Comments about Obesity and Health

12. Definitions for adults Body mass index (BMI) – weight/height 2
Underweight: BMI < 18.5
Normal weight: BMI 18.5-<25
Overweight*: BMI 25-<30
Obesity: BMI 30 +
BMI 18.5
BMI 25
BMI 30
162 cm (64 in)
49 kg (107 lbs)
66 kg (145 lbs)
79 kg (174 lbs)
178 cm (70 in)
59 kg (129 lbs)
95 kg (209 lbs)
* WHO defines overweight as BMI 25+
Courtesy of Katherine Flegal

13. Courtesy of Katherine Flegal
SOURCE: Harris 2008 Int J Obesity
Courtesy of Katherine Flegal

14. Courtesy of Katherine Flegal
SOURCE: Harris 2008 Int J Obesity
Courtesy of Katherine Flegal

15. Courtesy of Katherine Flegal
SOURCE: Harris 2008 Int J Obesity
Courtesy of Katherine Flegal

16. Courtesy of Katherine Flegal
SOURCE: Harris 2008 Int J Obesity
Courtesy of Katherine Flegal

17. Courtesy of Katherine Flegal

18. Obesity and Diabetes
We hear a great deal, in both the scientific literature and popular press, about the epidemics of obesity and diabetes
In fact, some dummies even use the term “diabesity”
What is the rate of type 2 diabetes in U.S. individuals under 45 years of age?

19. U.S. Rates of Diagnosed Type 2 Diabetes in Persons under 45 Years of Age in 2010
1.4%
Of course this is higher than it was in 1980
0.6%
Diagnosed diabetes in those under 20 years of age in the U.S.
0.26%
Source: CDC website--

20. Body Mass Index and Mortality

21. Relation between mortality and BMI
Figure 1. Relation between mortality and BMI. At a BMI below 20 kg/m2 and above 25 kg/m2, there is an increase in relative mortality for men and women. Data from Lew EA: Mortality and weight: insured lives and the American Cancer Society studies. Ann Intern Med 103: , Reprinted with permission from the author of Ref. 46.
Data from Lew EA: Mortality and weight: insured lives and the American Cancer Society studies. Ann Intern Med 103: , 1985.

22. Excess deaths associated with underweight, overweight and obesity [Reference Range 18.5 – 24.9]
82,066
29,843
33,746
BMI 30+: 111,909 deaths
-86,094
Flegal et al JAMA 293:1861, 2005

23. It’s calories that count
Energy Out
Energy In
Portion size
High-fat foods
Energy dense
Low-fiber
Soft drinks
Snack foods
BMR
Thermic effect of food
Media (TV,PC)
Cars
No heavy labour
Exercise
Causes of the Obesity Epidemic

24. 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?

25. Trends in Energy Intake NHANES 1971-2000
Data sources
NHANES I—
NHANES II—
NHANES III—
NHANES—
Surveys were representative samples of noninstitutionalized U.S. women and men aged 20 to 74 years
Is the Average Total Daily Caloric Intake Increasing?
Source: MMWR Feb 6, 2004

26. Trends in Energy Intake 1971 to 2000, Men, NHANES
Kcal/day
Source: MMWR Feb 6, 2004

27. Trends in Energy Intake 1971 to 2000, Women, NHANES
Kcal/day
Source: MMWR Feb 6, 2004

28. 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

29. Jobs in U.S. Over Last 50 Years
Trends in Energy Expenditure
Church TS et al. PLoS One 2011

30. Physical Activity Intensity
Church TS et al. PLoS One 2011

31. Daily Occupational Caloric Expenditure
-140 daily kcals
-120 daily kcals
Church TS et al. PLoS One 2011

32. Men: Predicted vs. NHANES
Church TS et al. PLoS One 2011

33. Women: Predicted vs. NHANES
Church TS et al. PLoS One 2011

34. The Energy Balance Study

35. Timeline
Your participation in the study will last approximately 13 months.
All enrolled participants will be asked to complete all scheduled measures.
Your participation in the study will last approximately 13 months over 10 total visits.
All enrolled participants will be asked to complete all scheduled measures.
Since this is a long study, we ask you to consider your schedule over the next 13 months. If you anticipate a major life event, such as moving out of the area or becoming pregnant, we ask you to reconsider your involvement at this time.
It is important to know that this is neither a weight-loss study nor an exercise study. We are collecting very specific information over an extended period of time in the hope of answering the ‘energy balance’ question.
Today
Activity assessment
Baseline Visits 1-3
Month 3
Month 6
Day 7
Day 14
Month 9
Month 12
3 Baseline Visits
-2-3 weeks-
6 Follow-up Visits
-12 months-
-2 weeks-

36. Food Portion-size Training
Purpose: to help estimate food portion sizes
Helpful for dietary recalls.
Time: 10 minutes.
The purpose of food portion-size training is to help you estimate food portion sizes that you will ask to remember during the dietary recalls you will participate later in the study. One of our dieticians will teach you how to identify how much you are eating using tips and some handouts. For example, the dietician will help you figure out what a ½ cup of pasta, like in this picture, looks like. This training will take about 10 minutes. I’ll talk about the recalls shortly.

37. Dietary Recalls
Dietician will call and ask what you ate the previous day.
Time: minutes
Three random recalls will occur
after your Baseline Visit 3.
Every time you wear the physical activity monitors throughout the study, you will be randomly called by our dietician and ask you what you ate the previous day. You will not record how much you eating using something like a diary; this is when the food portion-size training will be helpful.

38. Physical Activity Monitors
You will be wearing 2 monitors
Armband
Lightweight monitor worn on the upper left arm
Estimates energy expenditure and physical activity
ActivPAL
Small device worn on your thigh (under clothing)
Measures sitting and lying down time.
Both monitors should be worn at all times except in water
Wear for 10 days
Following the measurement of resting metabolic rate, you will be provided with two methods of assessing physical activity.
The first is an armband, like the one I am wearing right now. It will be worn on the upper left arm and it estimates your energy expenditure and physical activity.
The second is the ActivPal, which is secured to your thigh using either cloth or clear tape. This measures when you are sitting or lying down.
Both of these monitors will be worn at all times including sleep, except when you will be getting wet such as showering or swimming. You will wear these monitors for 10 days.
It is important to note that these devices do not track where you are at or what you are doing. They only measure if you are being active and how intense that activity is.

39. Body Composition Scan ~20-25 minutes It measures:
Fat mass
Lean mass
Requires small radiation exposure.
Less than 1 day's exposure to the sun.
(~ 3 hours of lawn mowing)
The body composition scan will take about minutes and will measure your fat mass and lean mass. This procedure does require a small amount of radiation exposure, a level equal to less than 1 day’s exposure to the sun or much less than the amount of an x-ray at the dentist office.

40. Resting Metabolic Rate
Measures the number of calories you burn at rest.
Participant rests:
45-60 minutes
Quiet room
The resting metabolic rate measures the number of calories you burn while you are resting. This test will take about 45 minutes, during which you will rest quietly in a room. Much like the exercise test, we will analyze the air you breathe out on a machine, only now you are resting rather than exercising. Since this test will last about 45 minutes, we will use this bubble you see here rather than a mouthpiece, nose clip, and headgear like the exercise test. Just like the mouthpiece device had one side that was open, you can see the hole in the top of the bubble to allow you to breathe in room air.

41. Cardiorespiratory Fitness, BMI, and Mortality, ACLS Men
25,389 men followed 8.5 years
673 deaths in 212,364 MY
Cardiorespiratory fitness assessed by a maximal exercise test
Calculated age-adjusted death rates for BMI and fitness categories
Is too much attention given to obesity and not enough to physical activity?
Barlow et al. Int J Obes 1995; 19:Suppl 4, S41-4

42. Assessment of Body Weight
I do not like to subject study participants to the embarrassment of actually measuring their weight, since so many are overweight/obese
We have an undergraduate student estimate height and weight of the participants
We did a validation study by actually measuring height and weight of 100 consecutive participants
The student’s estimate was valid, r=0.4

43. Age-Adjusted Death Rates by Fitness and BMI Categories
Deaths/10,000 MY
# deaths
Man-Yrs 25, , , , ,749 7, , ,240
Results held after adjustment for health status, smoking, glucose,
cholesterol, & BP
Barlow et al. Int J Obes 1995; 19:Suppl 4, S41-4

44. Assessment of Body Weight
I do not like to subject study participants to the embarrassment of actually measuring their weight, since so many are overweight/obese
We have an undergraduate student estimate height and weight of the participants
We did a validation study by actually measuring height and weight of 100 consecutive participants
The student’s estimate was valid, r=0.4

45. RR for All-cause and CVD Mortality in Fit and Unfit
ACLS Men by Body Fat Categories
Body Fat%
Body Fat%
All-cause Mortality
CVD Mortality
*adjusted for age, exam year, smoking, alcohol, & parental history
Lee CD, Blair SN, & Jackson AS. Am J Clin Nurt 1999; 69:373-80

46. Adjusted RR for All-Cause Mortality by Fitness and Waist Circumference
Waist circumference measurements in a subgroup 14,043 men
162 deaths in 78,008 man-years
RR adjusted for age, examination year, smoking habit, alcohol intake, and parental history of CHD
<87
87-<99
99
Lee CD, Blair SN, & Jackson AS. Am J Clin Nurt 1999; 69:373-80

47. Adjusted RR for All-Cause Mortality by Fitness and BMI, ACLS Women
*adj for age,
exam year,
smoking,
& health
status
Farrell et al. Obes Res. 2002; 10:

48. Joint Associations of CRF and % Body Fat with All-cause Mortality, ACLS Adults 60+
Death rate/1,000 person-years
Deaths
Rates adjusted for age, sex and exam year
Sui M et al. JAMA 2007; 298:

49. CVD Mortality Risk* by Fitness and BMI Categories, 2316 Men with Diabetes, 179 CVD Deaths
p for trend <0.0001
p for trend <0.0001
p for trend <0.002
Fitness, Fatness, and Mortality in Men with Type 2 Diabetes
Church TS et al. Arch Int Med
2005; 165:2114
*Adj for age and examination year

50. Based on strength of association Prevalence of the condition
Attributable Fractions of Health Outcomes For Low Cardiorespiratory Fitness and Other Predictors, ACLS
Attributable fraction (%) is the estimated number of deaths due to a specific characteristic
Based on strength of association
Prevalence of the condition
Attributable Fractions

51. Relative Risks and Attributable Fractions of All-Cause and CVD Mortality by BMI Categories in Men
25,714 (1,025 all-cause and 439 CVD deaths) men aged ≥20 years in the ACLS.
10 years of follow-up.
Attributable fractions are adjusted for age, examination year, BMI, parental history of CVD, and each other item in the table.
Wei M. et al., JAMA, 1999

52. Relative Risks (RR) and Attributable Fractions (AF) of All-Cause Mortality by BMI Categories in Men
Normal
Overweight
Obese
RR (95% CI)
AF, %
Baseline CVD
2.3 ( ) 19
2.0 ( )
2.4 ( ) 27
Diabetes
1.3 ( ) 2
1.6 ( ) 6
1.5 ( ) 9
High cholesterol
1.0 ( )
1.3 ( ) 8
1.7 ( ) 18
Hypertension
1.5 ( ) 12
1.4 ( ) 13
1.1 ( ) 4
Current smoker
1.4 ( ) 7
1.5 ( )
Low fitness
1.6 ( ) 10
1.7 ( )
2.3 ( ) 44
Wei M. et al., JAMA, 1999

53. Summary
Indicators of obesity and physical inactivity are predictors of morbidity and mortality
Cardiorespiratory fitness is an objective marker of habitual physical activity
Adjustment for cardiorespiratory fitness dramatically attenuates or eliminates associations of obesity markers and most health outcomes

54. 2008 Physical Activity Guidelines for Americans At-A-Glance
Today I am here to introduce the Physical Activity Guidelines for Americans to you that the U.S. Department of Health and Human Services developed and released in October 2008.
U.S. Department of Health and Human Services

55. Physical Activity Guidelines
For all individuals, some activity is better than none. More is better.
For fitness benefits, aerobic activity should be episodes of at least 10 minutes.
Physical activity is safe for almost everyone. The health benefits of physical activity far outweigh the risks.
Some physical activity is better than none, and adults who participate in any amount of physical activity gain some benefits.
More is better. For most health outcomes, additional benefits occur as the amount of physical activity increases.

56. Key Guidelines – Adults (ages 18–64)
Minimum levels a week
2 hours and 30 minutes (150 minutes) moderate-intensity aerobic activity; or
1 hour and 15 minutes (75 minutes) vigorous-intensity aerobic activity; or
An equal combination
Muscle-strengthening activities that involve all major muscle groups should be performed on 2 or more days of the week.
What are the Key Guidelines?
At a minimum, all adults should aim for 150 minutes of moderate-intensity or 75 minutes of vigorous aerobic activities each week. Notice that it takes less time to get the same benefit from vigorous than the moderate activities. A general rule is that 2 minutes of moderate counts the same as 1 minute of vigorous activities.
The Physical Activity Guidelines offer choices. Episodes of activity that are at least 10 minutes long count toward meeting the Guidelines.
For adults who are currently inactive, start with a small amount of physical activity and slowly increase activity over a period of weeks to months to meet the Guidelines.
Note: Major muscle groups are legs, hips, back, chest, abdominals, shoulders, and arms.

57. Key Guidelines – Adults (ages 18–64) (cont.)
For additional health benefits
5 hours (300 minutes) moderate-intensity aerobic activity a week; or
2 hours and 30 minutes (150 minutes) vigorous-intensity aerobic activity a week; or
An equivalent combination
The more time adults are active, the more health benefits they gain.
If adults increase beyond twice the minimum amount of activity they will gain even more benefits.

58. Overview
Medical care costs in the U.S are ~17% of GNP, by far the highest in the world
By traditional public health markers such as longevity, chronic disease rates, infant mortality, etc; the U.S. ranks far behind many other countries
Most health problems are the result of unhealthy lifestyles
We must be more aggressive in integrating lifestyle interventions into medical practice and public health programs

59. How to Promote Healthful Lifestyles
Relatively new area of research
Application of theories, models, & methods from behavioral science
Social Cognitive Theory, Transtheoretical Model (Motivational Readiness), etc
Helping individuals use cognitive and behavioral strategies to implement behavioral change

60. Lessons Learned from Physical Activity Intervention Studies
Individuals who use cognitive and behavioral strategies are more likely to be active at 24 months than individuals who do not use these strategies
Approximately 25-30% of initially sedentary persons who participate in Active Living will be meeting consensus public health guidelines for physical activity at 24 months

61. Behavioral Approaches to Physical Activity Interventions
Theoretical foundations
Social Learning Theory
Stages of Change Model
Environmental/Ecological Model
Methods
Problem solving
Self-monitoring
Goal setting
Social support
Cognitive restructuring
Incremental changes
Manipulating the environment

62. Active Living Every Day
S Blair takes no personal royalties from the ALED book

63. How to Achieve Lifestyle Change
Counseling by a PhD level behavioral psychologist
Counseling by B.A. level health educators
Counseling by mail and telephone
Counseling by electronic communications

64. LEAN Study Design RCT with 4 arms:
1.) Standard Care group included self-help with a diet and PA manual
2.) GWL health counselor and 14 sessions
3.) GWL + SenseWear™ Armband group
4.) SWA alone
Follow-up data collection visits occur at month 4 and month 9

65. Compared to themselves
No weight loss at month 4 (P=0.23), but there is significant weight loss at month 9 for GWL (P=0.05).
There is significant weight loss at month 4 and at month 9 for GWL+Armband (both P < ).
There is significant weight loss at month 4 and at month 9 for Armband alone (both P < 0.01).
No weight loss at month 4 or month 9 for Standard care (both P > 0.05).
All compared to the GWL
At month 4, no significant difference in weight between GWL and GWL+Armband (P=0.23) which means GWL+Armband produced weight loss comparable to the GWL over 4 months.
At month 9, there is borderline significant difference in weight between GWL and GWL+Armband (P=0.06) which means GWL+Armband produced weight loss greater than the GWL over 9 months.
At month 9, no significant difference in weight between Armband alone and GWL (P=0.44) which means Armband alone produced weight loss comparable to the GWL over 9 months.
All compared to the Standard Care
At month 4, no significant difference in weight between any of the three intervention groups comparing with the Standard care group (All p>0.05).
At month 9, there is significant difference in weight between GWL+Armband and the Standard care (P=0.02).
Effects across time for weight. Estimates adjust for age, gender, race, education, and wave.

66. How Should We Deal with the Obesity Epidemic?
Understand energy balance
Design interventions to address the problem
Public policy
Educational programs
Clinical medicine
Technological lifestyle interventions
Conduct research to test interventions
Implement successful interventions
Thank you Questions?