Download 37321-37331

The crucial role of physical
activity in the prevention and
management of overweight and
obesity
Dunedin, New Zealand
February 1, 2010
Steven N. Blair
[email protected]
Departments of Exercise Science &
Epidemiology/Biostatistics
University of South Carolina
•Fewer •Pressure
meals at
to be
home
sedentary
•Society of spectators
instead of participant
•Pressure
to consume
•Eatin
•Eating as g on
recreation the
run
•Powerful and
constant
advertising
Social Environment
Building design
Urban
sprawl
Absence of
Pollutants
sidewalks
Population Automobile
density
dependency
Energy Intake
Genetic
Predisposition
Viruses
Nutrient
/ Energy
Obesity
Partitioning
Overweight
Energy
Expenditure
Thermogenesis n-6/n-3 PUFAs
Lipid ox
Calorie- MaternalBehavior
dense
fetal
foods nutrition Smoking cessation
More sedentarism Less physical activity
Lactation High Corn fructose syrup
fat
Larger
portions diets
Certain
medications
Physical Environment
RMR
Regulators of adipogenesis:
RAR, RXR, PPARg, C/EBP,
SREBP-1c, PGC-1, etc.
Adipogenesis
Genetic CNS regulators of appetite: NPY,
hypotheses a-MSH, CART, Orexins, Agouti,
MC4R, MCH, AGRP, etc.
Epigenetics
Peripheral regulators of
appetite: PYY, insulin, leptin,
Biology
ghrelin, CCK, GLP-1, etc.
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
Leading Causes of Death in
the World
Risk Factor
Deaths
(millions)
% of total
deaths
Hypertension
7.5
12.8
Tobacco use
5.1
8.7
High blood glucose
3.4
5.8
Physical inactivity
3.2
5.5
Overweight/obesity
2.8
4.8
WHO. Global Health Risks. 2009.
Aerobics Center
Longitudinal Study
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
All-Cause Death Rates by CRF
Categories—3120 Women and
10 224 Men—ACLS
Age adj death rate/10,000
PY
70
Women
Men
60
50
40
30
20
10
0
Low
Moderate
High
Blair SN. JAMA 1989
Amount of Specific Physical Activities for
Moderately Fit Women and Men
• Detailed physical
activity assessments Mean Min/week
160
in women and men
who also completed a 140
maximal exercise test 120
100
• Average min/week for
80
the moderately fit
60
who only reported
40
each specific activity
20
Walk
Aerobics
Run
0
Women
Stofan JR et al. AJPH 1998; 88:1807
N=3,972
Men
13,444
Death Rates and RR for Selected
Mortality Predictors, Men, ACLS
Mortality
Predictors
Low Fit
Smoking
SBP>140
Chol>240
BMI>27
All-Cause Mortality
Deaths/10,000 Relative
MY
Risk
45.5
2.03
42.7
1.89
43.6
1.67
37.0
1.46
34.3
1.33
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
Death Rates and RR for Selected
Mortality Predictors, Women, ACLS
Mortality
Predictors
Low Fit
Smoking
SBP>140
Chol>240
BMI>27
All-Cause Mortality
Deaths/10,000 Relative
WY
Risk
28.8
2.23
29.0
2.12
15.1
0.89
18.9
1.16
19.5
1.18
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
Deaths/10,000 MY*
Cardiorespiratory Fitness, Risk
Factors and All-Cause Mortality, Men,
ACLS
60
50
40
# of risk factors
30
2 or 3
20
10
0
1
0
Risk Factors
High
Mod
Low
current smoking
Cardiorespiratory Fitness Groups
SBP >140 mmHg
*Adjusted for age, exam year, and other risk factors Chol >240 mg/dl
Blair SN et al. JAMA 1996; 276:205-10
CRF and Digestive System
Cancer Mortality
•38,801 men, ages 20-88 years
•283 digestive system cancer
deaths in 17 years of followup
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
CRF and Breast
Cancer Mortality
•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
Sui X et al. MSSE 2009; 41:742
Odds Ratio
p for trend=0.04
Age, examination year adjusted metabolic
syndrome incidence rates by cardiorespiratory
fitness in 10,221 men from ACLS 1977-2005
Rate per 1,000 men-yrs
200
175
150
125
P trend < 0.0001
100
75
50
25
0
<7.0
8.08.9
10.010.9
12.012.9
Maximal METs
14.014.9
≥16.0
Activity, Fitness, and
Mortality in Older Adults
Cardiorespiratory Fitness and All-Cause
Mortality, Women and Men ≥60 Years of Age
• 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
All-Cause death rates/1,000 PY
45
40
35
Low
Moderate
High
30
25
20
15
10
5
0
60-69
70-79
80+
Age Groups
Sui M et al. JAGS 2007.
We will all die eventually,
but
Who wants to spend
their last years in a
nursing home?
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
Low
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
Moderate
High
Women
Men
Huang et al. MSSE 1998, 30:1430-5
Cardiorespiratory Fitness and
Risk of Dementia, ACLS
• 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
Hazard Ratio
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
P for trend=0.002
Low
Moderate
High
Fitness Categories
Lui R et al. In review
Exercise Is Medicine
Physical Activity as
Treatment for Chronic
Disease
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
18
P <.001
P <.001
P =.048
16
CRF:
14
Low
Moderate
High
12
10
8
6
4
2
0
Controlled HTN
Stage 1 HTN
Severity of HTN
Stage 2 HTN
Sui X et al. Am J Hyptertension. 2007
Physical Activity and Survival
2987 Women with Breast Cancer
Nurses’ Health Study
Multivariable adjusted relative risk
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
Similar findings
for breast cancer
recurrance
<3
3-8.9
9-14.9 15-23.9
24+
Physical Activity in MET-hours/Week
Holmes MD et al. JAMA 2005; 293:2479
Yes, But Those Are
Observational Studies, and
We Require Randomized
Clinical Trial Evidence
Exercise Is As Good As Other
Treatments for Clinical Depression
% of Patients with Remission of
Depression
50
40
30
20
10
0
Control
80 Min/Week
180 Min/Week
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
Exercise Training and Angioplasty,
101 Men with Stable CAD
Event-free survival (%)
90
80
Per unit change in
$7,000
angina-CCS
70
$6,000
60
$5,000
50
$4,000
40
$3,000
30
$2,000
20
$1,000
10
0
$0
Exercise
Angioplasty
Exercise
Angioplasty
Exercise was 20 minutes/day
Hambrecht R et al. Circulation 2004; 109:1371
on a cycle ergometer
Reduction in Risk of Developing
Diabetes in Comparison with Controls,
DPP
Risk reduction (%)
100
*Moderate intensity exercise
80 of 150 min/week; low
calorie, low fat diet
58%
60
40
31%
20
0
Lifestyle
Intervention*
DPP Research Group. NEJM 2002; 346:393-403
Metformi
n
Cost Effectiveness of Diabetes
Prevention-DPP
Metformin
Per QALY
Gained
DPP Res Group. Diab Care 2003; 26:2518
Lifestyle
Per Case
Delayed/Prev
• 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
$100,000
$90,000
$80,000
$70,000
$60,000
$50,000
$40,000
$30,000
$20,000
$10,000
$0
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
It’s calories that count
Energy In
Portion size
High-fat foods
Energy dense
Low-fiber
Soft drinks
Energy Out
Media (TV,PC)
Cars
No heavy labour
However, Energy Balance Is
Poorly Understood
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.”
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
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?
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
Is the Average Total Daily
Caloric Intake Increasing?
Trends in Energy Intake
NHANES 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
Trends in Energy Intake
1971 to 2000, Men, NHANES
Kcal/day
3000
1971-74
1976-80
1988-94
1999-00
2500
2000
1500
1000
500
0
All Ages
20-39 y
Source: MMWR Feb 6, 2004
40-59 y
60-74 y
Trends in Energy Intake
1971 to 2000, Women, NHANES
Kcal/day
2500
1971-74
1976-80
1988-94
1999-00
2000
1500
1000
500
0
All Ages
Source: MMWR Feb 6, 2004
20-39 y
40-59 y
60-74 y
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
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
BRFSS Trend Data, Women and Men
Hypothesis Regarding Energy
Intake, Expenditure, and Balance
Energy balance
kcal
intake
Normal distribution of
susceptibility to dysregulation
kcal expenditure
Jim Hill & Russ Pate contributed to the concept
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
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”
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
Energy Requirement for
Subsistence Farming
In bed at 1 MET
8 hours
Occupational activities at 2.7 7 hours
METs
Household tasks at 3.0 METs 2 hours
Exercise
--
Residual time at 1.4 METs
7 hours
Total energy expenditure (PAL)=1.78
FAO/WHO Joint Consultation. Energy & Protein
Requirements. WHO Technical Report Series #724
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?
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/
Prevention of Weight Gain
with Physical Activity
Observational Studies
Weight Change over Time
by PAL Change Groups
Kg
PAL Change Groups
Low<1.45;Mod=1.45-1.60;Hi=>1.60
79
Green lines are significantly
different from the reference
78
category (Low-Low)
77
76
Estimates adjusted for
75
baseline weight,
74
age, sex, height, & change
in weight
73
Years 0
2.5
5
DiPietro et al. IJO 2004; 28:1541
Low-Mod
Low-High
7.5
10
Leisure-Time Physical Activity and
10-year Change in Body Mass
• Representative cohort of 19-63 year old Finnish
women (n=2695) and men (n=2564)
• Physical activity assessed at baseline and follow-up
– Which of the following categories best describes
your physical activity during the past 12 months?
• Vigorous activity 2 times/week
• Vigorous activity once/week and some light
activity
• Some activity each week
• No regular weekly activity
Haapanen N et al. Int J Obes 1997; 21:288-96
Leisure-Time Physical Activity and
10-year Change in Body Mass
• Change in activity from 1980 to 1990
– Physically active all the time (vigorous
activity 1 time/week in both 1980 & 1990
– Physically activated (no vigorous activity in
1980 but at least 1 time/week in 1990)
– Physically inactivated (vigorous activity 1
time or more/week in 1980 but not 1990)
– Physically inactive all the time (no vigorous
activity in either 1980 or 1990)
Haapanen N et al. Int J Obes 1997; 21:288-96
Leisure-Time Physical Activity and
10-year Change in Body Mass
kg
2
1.5
P Active all the time
Phys Activated
Phys Inactivated
P Inactive all the time
1
0.5
0
-0.5
Women
Men
Adj for age, health status, smoking, and SES (men only)
Haapanen N et al. Int J Obes 1997; 21:288-96
Physical Activity Change and
Weight Change over 10 Years,
CARDIA
Wt change, kg/year
0.8
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
-1
-1.2
Wt change, regardless of
PA change
Weight attenuation, 200
exercise units
B women W women
B men
W men
Schmitz KH et al. Int J Obes 2000; 24:1475-87
Prevention of Weight Gain
or Weight Loss with
Physical Activity
Experimental Studies
Mean Energy Expenditure
kcal.kg-1 .day-1
Lifestyle
Structured
35
34
33
32
0
6
12
18
24
time in months
Dunn et al. JAMA 1999; 281:327
Project Active
24-Month Change in Weight
and Percent Body Fat
Percent
Body Fat
kilograms
1.5
0
-1.5
1.5
0
-1.5
Lifestyle
Structured
*
*
-3
* p < 0.001 within group
Dunn et al. JAMA 1999; 281:327
percent
Weight
-3
Project Active
Dose-Response to Exercise
in Post-Menopausal Women
(DREW)
Randomized
(n = 464)
Control
(n = 102)
Low Dose
(n = 155)
Mod Dose
(n = 104)
High Dose
(n= 103)
Completed (94)
Withdrawn (8)
Completed (145)
Withdrawn (10)
Completed (89)
Withdrawn (15)
Completed (96)
Withdrawn (7)
330 women (91%) out of 362 completed the
6 month exercise program
Total Adherence
110.0
100.0
Adherence (%)
90.0
80.0
70.0
60.0
50.0
40.0
30.0
20.0
227 had 100% adherence
269 had >99% adherence
10.0
0.0
0
30
60
90
120 150 180 210 240 270 300 330
Participants (n=330)
*Does not include participants who withdrew.
Percent Change Fitness
Change in Fitness
9.1
10
8
6.7
6
3.8
4
2
0
-2
-1.7
-4
Control
72 Minutes
136 Minutes
192 Minutes
Study Groups
Church TS et al. JAMA, 2007; 297: 2081-2091
Change in Weight
TS Church et al. JAMA 2007
•All groups significantly decreased weight
•Compared to Group A:
•Only group C had a significant decrease in
weight (p<0.05)
0
1.1%
1.5%
2.2%
1.5%
Change Kg
-0.5
-1
-0.9
-1.5
-1.4
-2
-1.4
-1.9
-2.5
-3
Control
75 minutes
150 minutes
Study Groups
225 minutes
Change in Waist Circumference
TS Church et al. JAMA 2007
•Significant decrease in WC occurred in all exercise groups
(p<0.01
all groups)
2
Change CM
1
0.3
All significant versus control
0
-1
-2
-3
-3
-4
-2.7
-2.8
150 minutes
225 minutes
-5
Control
75 minutes
Study Groups
Actual vs Predicted Weight Loss,
DREW—4 KKW
Church TS et al. PLOS One 2009; 4:4515
Actual vs Predicted Weight
Loss, DREW—8 KKW
Church TS et al. PLOS One 2009; 4:4515
Actual vs Predicted Weight Loss,
DREW—12 KKW
Church TS et al. PLOS One 2009; 4:4515
Percent of Expected Weight
Loss, DREW
P = 0.05
Percent of Expected (%)
140
124
120
99.5
100
42
80
60
40
20
0
4 KKW
8 KKW
Exercise Dose
Church TS et al. PLOS One 2009; 4:4515
12 KKW
Summary
• Some form of compensation
is taking place in the 12 KKW
but not 4 or 8 KKW groups
Caloric Balance
Intake
+
Resting Met Rate
Thermic Effect of Food
Spontaneous Activity
Exercise
_
Caloric Balance
Intake
+
Resting Met Rate
Thermic Effect of Food
Spontaneous Activity
Exercise
_
Spontaneous Activity
4 KKW
8 KKW
12 KKW
Daily Steps Exclusive of
Training
6000
5500
5000
4500
4000
3500
3000
0
1
2
3
Months
4
5
6
Caloric Balance
Intake
????
+
Resting Met Rate
Thermic Effect of Food
Spontaneous Activity
Exercise
_
Intake via Food Frequency
Questionaire
Daily Caloric Intake
3000
2500
2000
1500
1000
500
0
4 KKW
8 KKW
Study Groups
12 KKW
Summary
• There were no significant differences
between groups B, C, and D on either
WC or weight.
• 6 months of aerobic exercise training
decreases central adiposity in
sedentary postmenopausal women
• Similar reductions in WC across
exercise groups suggest a threshold
effect versus a dose response
relationship between exercise and WC
Conclusions
• There appears to some form of caloric
compensation with higher doses of exercise
• At this point we can only hypothesize about the
source(s) of compensation
• Emphasizes the importance of addressing intake
when prescribing exercise for weight loss
• Next Steps:
– Confirm our findings
– Explore reasons
• Gender Effects
• Better Quantify non-exercise activity
• Psychology of eating
– Triggers?
• Energy storage issue
• Amount versus composition of intake
How Much Activity Is
Required to Prevent Weight
Regain after Weight Loss?
Percent Change in Weight Loss
Based on Exercise Participation
% Weight Loss
0 months
6 months
12 months
0
-2
-4
-6
-8
-10
-12
-14
-16
a
b
a,b
EX>200
EX>150
EX<150
EX-OTHER
Note: Groups with the same letters are significantly different at 12 months based on Bonferroni adjustment (p<0.05).
Jakicic, et al. JAMA. 2003
Kcals / week
Average Energy Expended In
Physical Activity In The NWCR
4000
3000
3293
2545
2682
Women
2000
Men
1000
All
Subjects
0
Klem et al, AJCN 1997;66:239-46.
Summary
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 (%) for
All-Cause Deaths
40,842 Men & 12,943 Women, ACLS
18
16
14
12
10
8
6
4
2
0
Men
Women
Lo
w
CR
Ob
F
es
e
Sm
ok
er
Hy
pe
Hi
gh
rt
en
si
on
Di
ab
et
Ch
es
ol
Blair SN. Br J Sports Med 2009; 43:1-2.
Final Message
• Focus on
– Healthful eating habits
• Fruits and vegetables
• Whole grain
– Regular physical activity
• Three 10 minute walks/day
Thank you
Questions?