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Diet, Exercise, and
Cancer Risk
Diane Baer Wilson, EdD, MS, RD
Associate Professor Division of Quality Healthcare
Department of Internal Medicine
Co-Director Cancer Prevention and Control
Massey Cancer Center
Virginia Commonwealth University
CCFellows2-13-06
Today’s objectives
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Examine dietary-related factors and
physical activity related to cancer risk
Discuss dietary fat as a model for
dietary studies related to cancer risk
Review nutrition measurement methods
Examine recent research related to BMI
and breast cancer
“Genes load the gun. Lifestyle pulls
the trigger.”
Elliott Joslyn, MD
Cancer risk factors
Age
 Family history
 Hormone exposure
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 Tobacco use
 Diet/exercise
 Environmental exposures
 Alcohol Intake
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Cancer Risk Factors:
Nutrition
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Top Issues:
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Energy Balance
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Weight
Exercise
Nutrient Composition
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Dietary Fat
Fruit/Vegetables
Fiber
Soy
Understanding dietary
fat/cancer hypotheses
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Nutrition relatively recent area of cancer
research
Research seeds:
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Correlational
Animal research
Cross sectional
RCT
Fat intake/breast cancer,
Carroll, 1975.
Dietary Fat/Breast Cancer
Animal studies
Proportionate level of tumor growth
recorded in laboratory rats related to
level of dietary fat fed animals over
designated period of time.
(1975-1980’s)
Dietary Fat/Breast Cancer
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Human studies
Cross sectional
Nurses Health Study-Willett, et al, 2000.
Dietary Fat/Breast Cancer
Randomized Clinical Trial
“Low-fat Dietary Patterns and Risk of
Invasive Breast Cancer”
The Women’s Health Initiative Randomized
Controlled Dietary Modification Trial
Prentice, Caan, Chlewbowski, et al. JAMA
2006;295: 629-642. (2/8/06)
Participant Flow in the Dietary Modification Component of the Women's Health Initiative
Prentice, R. L. et al. JAMA 2006;295:629-642.
Copyright restrictions may apply.
Baseline Demographics of Participants in Women's Health Initiative Dietary Modification Trial*
Prentice, R. L. et al. JAMA 2006;295:629-642.
Copyright restrictions may apply.
Nutrient Consumption Estimates and Body Weight at Baseline and Year 1
Prentice, R. L. et al. JAMA 2006;295:629-642.
Copyright restrictions may apply.
Blood Biomarkers for Baseline and Year 3*
Prentice, R. L. et al. JAMA 2006;295:629-642.
Copyright restrictions may apply.
Risk of Invasive Breast Cancer and Other Major Clinical Outcomes
Prentice, R. L. et al. JAMA 2006;295:629-642.
Copyright restrictions may apply.
Breast Cancer Risk by Baseline Dietary Factors
Prentice, R. L. et al. JAMA 2006;295:629-642.
Copyright restrictions may apply.
Breast Cancer Risk Based on Baseline Demographics, Medical History, and Health Behavior
Variables
Prentice, R. L. et al. JAMA 2006;295:629-642.
Copyright restrictions may apply.
The American view of nutrition
information
Dietary Assessment
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Twenty-four hour dietary recall
Food frequency questionnaire
Diet record
Diet history
Data Collection Methods
24 hour recall method
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Most common method used for national
dietary surveys
Information on everything consumed over
past 24 hours-relies on memory
Trained interviewers
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non-judgmental
neutral
Food Record Method
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Detailed record of all foods consumed
on one or more days at time consumed
Less dependent on memory
Face to face training on completeness
and accuracy essential
Accurate portion reporting essential
Final record reviewed by professional
Food frequency questionnaires
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Food frequency surveys most common
measurement method in nutrition epi
research
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Average intake, “usual” intake
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Easy to complete
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Foods, clarity, format important
Approaches for Evaluating
Dietary Questionnaires
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Compare mean of nutrient intake
Proportion of intake accounted for
Reproducibility
Validity
Compare to biochemical indicator
Compare to physiologic indicator
Ability to predict disease
Food Recalls/Records
Foods Recalls and Records
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Based on specific foods consumed
Attempt to get data on one’s
“true intake”, open-ended
Can be representative if enough days
tested
Best method for comparing intake to
recommendations
Most used to validate FFQ
Designing and Administering
Questionnaires
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Motivated subjects
Clear instructions
Correct foods
Standardized procedures
Interview or telephone
Portion sizes?
Determining best method
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Individual intake or group mean?
Actual intake or relative ranking?
Open-ended method or structured list?
Age limitations?
Literacy considerations?
Overweight and breast cancer
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Women who are overweight are more
likely to:
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Develop breast cancer
Be diagnosed at a later stage
Have higher mortality rates
Overweight and Breast Cancer
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Review of 26 studies examining the
association of pre-morbid weight or
weight at diagnosis with recurrent
disease or survival (Rock and Wahnefried,
2002)
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17 found increased BMI significantly
associated with increased risk of death
2 null findings
7 inverse findings
Overweight and Breast Cancer
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Weight gain and increased risk
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Obesity increases peptide hormones-insulin
and steroid hormones-estrogen
Heaviest women have 3x level of estrogen
than lean women without HRT
Obesity increases risk of death from
breast cancer about as much as
mammography reduces it.
Breast Cancer Survivorship
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With early diagnosis, the survival rate
has significantly increased
22% of all cancer survivors are breast
cancer survivors
Breast cancer survivors comprise the
largest proportion of cancer survivors
Weight Gain
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Weight gain
60% of women report weight gain after
diagnosis
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more prevalent:
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premenopausal at diagnosis
received adjuvant chemotherapy
in African Americans
caloric intake
Reasons for weight gain:
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Likely to be at least “peri menopausal”
Being told to “keep your strength up”
during therapy
Comfort foods
Less exercise
Needs more research….
Exercise
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Type of exercise
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Walking vs. more rigorous forms
Breast cancer
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Multi beneficial
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Mental, physical, emotional
Integration
Addressing weight gain in African
American breast cancer survivors
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African American women have higher
mortality from breast cancer when compared
to Caucasian women
Some 60% of all women report gaining
weight after being diagnosed with breast
cancer. However, African American women
are especially at risk for this weight gain,
after diagnosis of breast cancer, placing them
at greater risk for cancer recurrence and
shorter survival time.
Testing an exercise intervention
in African American breast cancer
survivors (Study 1)
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Study Aim: Determine the feasibility and impact of a
cognitive, behavioral theory-based walking intervention,
Walking Counts! in a sample of AA breast cancer
survivors.
Feasibility: Attendance, compliance, process measures
Outcomes: Integration of regular exercise (steps/day)
change in BMI, waist, hip, forearm circumferences, body
fat %, blood pressure, attitude toward exercise and
cancer stress.
Walking Counts!-Methods
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Eligibility:
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Breast cancer diagnosis
>3 months past cancer treatment
Mobile
<70 years old
Description of the intervention:
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Health Belief Model
Eight week community-based, 75 minute sessions
Benefits, barriers, relationship to cancer risk,
Personal assessment/problem solving
Pedometers, scheduling, and tracking of steps/day
Wilson et al; Preventing Chronic Disease 2005
Walking Counts!-Results
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Feasibility
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Attendance-70% attended > 7 sessions
Retention: 92% retained
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1 dropped after enrollment due to scheduling
1 recurred
Pedometers
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Steps only mode
25% needed replacement
Walking Counts!-Results
Characteristics of the Sample
Age (yrs)
(n=22)
55 (39 – 66)
Weight (lbs)
191 (142 – 271)
BMI (kg/m2)
32.7 (25.2 –
47.2)
Education: (%)
< high school
High school graduate
Post high school
4.5
4.5
90.9
Marital Status: (%)
Married
Single/Divorced/Widowed
50
50
Characteristics of the Sample
Menopausal Status (%)
Pre
Post
13.6
86.4
Time Since Diagnosis: (%)
1-6 years
7-10 years
More than 10 years
59.1
13.6
27.3
Type of Treatment: (%)
Chemotherapy
Radiation therapy
Both
Neither
18.2
18.2
45.5
18.2
Tamoxifen: (%) Yes
No
22.7
77.3
Alcohol: (%) Yes
No
27.3
72.7
Smoking: (%) Yes
No
9.1
90.9
Walking Counts! Pre/Post Measures
Baseline (N=22)
Anthropometric measures:
Steps/day
BMI (kg/m2)
Weight (lb.)
Body Fat (%)
Waist circumference (in.)
Hip circumference (in.)
Arm circumference (in.)
Systolic B/P (mm Hg)
Diastolic B/P(mm Hg)
Waist to Hip ratio
4791
32.7
191.2
40.1
39.7
47.2
13.9
140.9
80.1
0.8
Attitudinal measures:
Exercise Attitude Total
Cancer Stress Total
* Paired “t-test” for difference in group means.
66.2
6.8
Change
p value*
+3506
- 0.38
- 2.0
- 3.4
- 1.8
- 0.87
- 0.58
- 10.1
- 6.2
- 0.02
<0.001
0.004
0.005
0.003
0.037
0.020
0.007
0.000
0.005
0.156
+ 3.0
- 0.36
0.029
0.201
Steps/day at Baseline, Post and
3 Month Post Intervention
9000
8000
7000
6000
5000
4000
3000
Baseline
p<.001 B/P***, p=.001*** B/3mth
Post
3 Months
Other research addressing
obesity
Nutrigenomics: Studies to help
understand the mechanism by which
genes may influence chronic disease
risk related to nutrients and obesity
Genes and obesity in breast
cancer
Study Aim: Measure breast cancer gene expression profiles and
analyze differences in tumor gene expression according to ethnicity
in lean (BMI <25) and overweight (BMI >30) women
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Methods: Using tissue samples taken at diagnosis of breast
cancer, we will study microarray expression of selected genes in 100
AA and 100 Caucasian women.
 Co-variates, include menopausal status, serum markers for
insulin resistance and obesity, dietary intake and level of physical
activity
Implications: Study results may help to identify molecular
changes and or genetic pathways in lean vs overweight women that
contribute to breast cancer outcomes.
(O’Connell P, Penberthy L, Wilson DB, Dumur K)
Other dietary trials:
Women’s Intervention Nutrition Study
(WINS)
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Tests effect of low-fat intervention on recurrence
in 2500 breast cancer survivors
Women’s Healthy Eating and Living
intervention
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3,109 survivors tests increased fr/veg intake, low fat, high
fiber on progression of disease
Other nutrition areas of
interest:
Soy
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Dual roles-low vs high levels
Food sources only
Soy protein 25 g/day
Isoflavones-genistein
Avoid supplements
Omega-3 fatty acids
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Slow growth of tumors in animals
May increase efficacy of
chemopreventive agents
Cold water fish
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Variable even within fish types
Flax seed
Canola oil
Supplements
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Cancer patients start consuming more
supplements and herbal products after
diagnosis
Health claims on labels are not all
official terms
Watch the research-many products are
in trials
What to eat?
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Emphasize plant based foods
Eat 5-10 servings of fruits/vegetables
chemopreventive constituents
fiber
antioxidants
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Eat less red-meat
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Pay attention to type of fat
Don’t eliminate fat
Eat more fish
Summary
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Nutrient driven hypotheses have significant
measurement threats to validity
Providing the public with sound nutritional
guidelines requires a thorough examination of
“the evidence”
The evidence for the role of obesity and that
for the role of exercise are among the
strongest for providing advice to the public
Much more scientific research is needed to
better understand the role of macro and
micro nutrients related to specific cancer risk.
“Nutrition is one of the most significant
determinants of health and one of the
most modifiable.” The US Surgeon General