Effects of Physical Activity on Cancer Risk

1
Effects of Physical Activity on Cancer Risk

• Mindy S. Kurzer
• Dept. of Food Science and Nutrition
• University of Minnesota
• St. Paul, Minnesota

2

• Does Physical Activity Reduce Risk of Breast
  Cancer?

3
Physical Activity and Breast Cancer A Systematic
ReviewEM Monninkhof et al. 2007Epidemiology
18(1) 137.
4
Cohort Studies on Physical Activity and Breast
Cancer
n19 studies 8 studies risk reduction (20-80)
Monninkhof et al 2007
5
Case-Control Studies on Physical Activity and
Breast Cancer Risk
n29 studies 14 studies risk reduction (20-65)
Monninkhof et al 2007
6
Studies on Physical Activity and Breast Cancer
Risk in Premenopausal Women
Cohort
n22 studies 10 studies reduced risk
Case- Control
Monninkhof et al 2007
7
Studies on Physical Activity and Breast Cancer
Risk in Postmenopausal Women
Cohort
n29 studies 20 studies reduced risk
Case- Control
Monninkhof et al 2007
8
Summary

• Best evidence increased leisure time activity is
  associated with reduced breast cancer risk in
  postmenopausal women (20-80 risk reduction)
• Evidence in premenopausal women is weaker
• Half the best studies showed dose-response
• 6 reduction in risk/hour physical activity/wk

Monninkhof et al 2007
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Association of Physical Activity with BC
Incidence is Influenced by ER/PR Status in the
Iowa Womens Health Study
Physical Activity Level
Bardia et al 2006
10
Lifetime Strenuous Physical Activity is
Associated with Reduced Breast Cancer
Hrs/wk
n107,034
P0.04
n110,599
P0.02
Relative Risk
Dallal et al 2007
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• Does Exercise Reduce Risk of Prostate Cancer?

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Physical Activity is Associated With Relative
Risk of Death From Prostate Cancer (n29,110)
P0.07
P0.28
P0.04
P0.49
Relative Risk
Nilsen et al 2006
13
Physical Activity Is Associated With Relative
Risk of Advanced Prostate Cancer (n29,110)
Summary Score Intensity Duration Frequency
P0.02
P0.39
P0.02
P0.04
Nilsen et al 2006
Relative Risk
14
Physical Activity is Associated With Relative
Risk of Aggressive Prostate Cancer (n72,174)
MET-h/wk
P0.06
P0.57
Patel et al 2005
Relative Risk
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• Does Exercise Reduce Risk of Colo-Rectal Cancer?

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Leisure Activity is Associated With Reduced Risk
of Colorectal Cancer in Swedish Men (n45,906)
P0.001
P0.11
P0.58
P0.38
Hazard Ratio
Larsson et al 2006
17
Leisure Activity is Associated With Reduced Risk
of Both Colon and Rectal Cancer in Swedish Men
(n45,906)
P0.01
P0.01
P0.17
P0.01
Hazard Ratio
Larsson et al 2006
18
Total Physical Activity is Associated With
Reduced Risk of Colon Cancer in EPIC Study
(n413,044)
P0.13
P0.35
P0.38
P0.04
Hazard Ratio
Friedenreich et al 2006
19
Physical Activity is Associated With Reduced Risk
of Right Colon Cancer in EPIC Study (n413,044)
P0.80
P0.05
P0.29
P0.004
Hazard Ratio
Friedenreich et al 2006
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Physical Activity is Associated With Reduced Risk
of Right Colon Cancer in EPIC Only in Non-Obese
Subjects (n413,044)




Hazard Ratio
Friedenreich et al 2006
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Vigorous Exercise is Associated With Reduced
Colorectal Polyps in African-American Women
(n45,400)


Relative Risk
Hours/wk
Rosenberg et al 2006
22
Vigorous Exercise Walking is Associated With
Reduced Colorectal Polyps in African-American
Women (n45,400)
MET-h/wk vigorous exercise walking
Relative Risk

Rosenberg et al 2006
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• Does Exercise Reduce Risk of Lung Cancer?

24
Physical Activity is Associated With Reduced Lung
Cancer Risk in Postmenopausal Women (n36,929)


Activity Level
Relative Risk
Sinner et al 2006
25
Physical Activity is Associated With Reduced Lung
Cancer Risk in Current and Former Smokers Only
(n36,929)
Activity Level
Relative Risk



Sinner et al 2006
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• Does Exercise Reduce Risk of Renal Cancer?

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Infrequency of Non-Occupational Physical Activity
is Associated With Increased Renal Cell Carcinoma
in Women (n220 cases)

Odds Ratio
Chiu et al 2006
28
Intensity of Leisure-Time Physical Activity is
Associated With Trend Toward Reduced Renal Cell
Cancer in Male Smokers (n29,133)
P0.12
Relative Risk
Mahabir et al 2003
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Suggested Associations

• Ovarian Cancer
• Hodgkins Lymphoma
• Endometrial Cancer

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Mechanisms by which Physical Activity May Reduce
Cancer Risk

• Steroid Hormones
• Females
• Males
• Immune System
• Oxidative Stress
• IGF-axis
• Energy Balance/Body Composition
• Direct Effects on Tumor

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Physical Activity is Associated with Lowered
Circulating Hormones in Postmenopausal Women
(n267)
MET-h/wk
pg/ml
Plt0.01
Plt0.01
McTiernan et al 2006
32
Aerobic Exercise Decreases Colon Crypt Cell
Proliferation in Men (n102)
Crypt Height (mm)
Minutes/wk
McTiernan et al 2006
33
ACS Recommendations

• Adults at least 30 minutes of moderate to
  vigorous physical activity, above usual
  activities, on 5 or more days of the week
• 45-60 minutes of intentional physical activity
  are preferable
• Children and adolescents at least 60 minutes/d
  of moderate to vigorous physical activity at
  least 5 days/wk