CCFellows2-13-06
Diet, Exercise, and Cancer Risk
Diane Baer Wilson, EdD, MS, RDAssociate Professor Division of Quality
HealthcareDepartment of Internal Medicine
Co-Director Cancer Prevention and Control Massey Cancer Center
Virginia Commonwealth University
Today’s objectives
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…… …… …… Tobacco use Diet/exercise Environmental exposures Alcohol Intake
Cancer Risk Factors: Nutrition Top Issues:
Energy Balance Weight Exercise
Nutrient Composition Dietary Fat Fruit/Vegetables Fiber Soy
Understanding dietary fat/cancer hypotheses
Nutrition relatively recent area of cancer research
Research seeds: 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
Human studies Cross sectional Nurses Health Study-Willett, et al,
2000.
Dietary Fat/Breast CancerRandomized 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)
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Prentice, R. L. et al. JAMA 2006;295:629-642.
Participant Flow in the Dietary Modification Component of the Women's Health Initiative
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Prentice, R. L. et al. JAMA 2006;295:629-642.
Baseline Demographics of Participants in Women's Health Initiative Dietary Modification Trial*
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Prentice, R. L. et al. JAMA 2006;295:629-642.
Nutrient Consumption Estimates and Body Weight at Baseline and Year 1
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Prentice, R. L. et al. JAMA 2006;295:629-642.
Blood Biomarkers for Baseline and Year 3*
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Prentice, R. L. et al. JAMA 2006;295:629-642.
Risk of Invasive Breast Cancer and Other Major Clinical Outcomes
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Prentice, R. L. et al. JAMA 2006;295:629-642.
Breast Cancer Risk by Baseline Dietary Factors
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Prentice, R. L. et al. JAMA 2006;295:629-642.
Breast Cancer Risk Based on Baseline Demographics, Medical History, and Health Behavior Variables
The American view of nutrition information
Dietary Assessment
Twenty-four hour dietary recall Food frequency questionnaire Diet record Diet history
Data Collection Methods
24 hour recall method Most common method used for
national dietary surveys Information on everything consumed
over past 24 hours-relies on memory Trained interviewers
non-judgmental neutral
Food Record Method
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 Food frequency surveys most common
measurement method in nutrition epi research
Average intake, “usual” intake
Easy to complete
Foods, clarity, format important
Approaches for Evaluating Dietary Questionnaires
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 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
Motivated subjects Clear instructions Correct foods Standardized procedures Interview or telephone Portion sizes?
Determining best method
Individual intake or group mean? Actual intake or relative ranking? Open-ended method or structured
list? Age limitations? Literacy considerations?
Overweight and breast cancer
Women who are overweight are more likely to: Develop breast cancer Be diagnosed at a later stage Have higher mortality rates
Overweight and Breast Cancer Review of 26 studies examining the
association of pre-morbid weight or weight at diagnosis with recurrent disease or survival (Rock and Wahnefried, 2002) 17 found increased BMI significantly
associated with increased risk of death 2 null findings 7 inverse findings
Overweight and Breast Cancer
Weight gain and increased risk 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
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
Weight gain 60% of women report weight gain
after diagnosis more prevalent:
premenopausal at diagnosis received adjuvant chemotherapy in African Americans caloric intake
Reasons for weight gain:
Likely to be at least “peri menopausal”
Being told to “keep your strength up” during therapy
Comfort foods Less exercise Needs more research….
Exercise
Type of exercise Walking vs. more rigorous forms
Breast cancer Multi beneficial
Mental, physical, emotional Integration
Addressing weight gain in African American breast cancer survivors
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)
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 Eligibility:
Breast cancer diagnosis >3 months past cancer treatment Mobile <70 years old
Description of the intervention: 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
Feasibility Attendance-70% attended > 7 sessions Retention: 92% retained
1 dropped after enrollment due to scheduling 1 recurred
Pedometers Steps only mode 25% needed replacement
Walking Counts!-Results
Characteristics of the Sample (n=22)
Age (yrs)
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) Change p value*
Anthropometric measures: Steps/day 4791 +3506 <0.001 BMI (kg/m2) 32.7 - 0.38 0.004 Weight (lb.) 191.2 - 2.0 0.005 Body Fat (%) 40.1 - 3.4 0.003 Waist circumference (in.) 39.7 - 1.8 0.037 Hip circumference (in.) 47.2 - 0.87 0.020 Arm circumference (in.) 13.9 - 0.58 0.007 Systolic B/P (mm Hg) 140.9 - 10.1 0.000 Diastolic B/P(mm Hg) 80.1 - 6.2 0.005 Waist to Hip ratio 0.8 - 0.02
0.156
Attitudinal measures: Exercise Attitude Total 66.2 + 3.0 0.029 Cancer Stress Total 6.8 - 0.36 0.201* Paired “t-test” for difference in group means.
Steps/day at Baseline, Post and 3 Month Post Intervention
3 MonthsPostBaseline
Me
an
Ste
ps P
er
Da
y
9000
8000
7000
6000
5000
4000
3000
p<.001 B/P***, p=.001*** B/3mth
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
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) Tests effect of low-fat intervention on
recurrence in 2500 breast cancer survivors
Women’s Healthy Eating and Living intervention
3,109 survivors tests increased fr/veg intake, low fat, high fiber on progression of disease
Other nutrition areas of interest:
Soy
Dual roles-low vs high levels Food sources only Soy protein 25 g/day Isoflavones-genistein Avoid supplements
Omega-3 fatty acids
Slow growth of tumors in animals May increase efficacy of
chemopreventive agents Cold water fish-
Variable even within fish types Flax seed Canola oil
Supplements
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? Emphasize plant based foods Eat 5-10 servings of fruits/vegetables
chemopreventive constituents fiber antioxidants
Eat less red-meat Pay attention to type of fat Don’t eliminate fat
Eat more fish
Summary 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