Environment and Breast Cancer: Science Review


Evidence From Humans
 
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Lifetime recreational exercise activity and risk of breast carcinoma in situ
Patel, A.V.,, Press, M.F.,, Meeske, K.,, Calle, E.E., Bernstein, L. Cancer. 2003. 98, 2161-2169.
Topic area
Physical Activity
Study design
Population based case-control
Funding agency
DOD NCI Other: National Institute of Child Health
Study Participants
Number of Cases
567 BCIS only (147 pre) (252 post) (475 white) (92 black)
Menopausal Status
The menopausal status of women included in this study is listed here.
Pre menopausal
Post menopausal
Number of Controls
Controls: (121 pre) (314 post) (364 white) (252 black)
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
In: white and black women age 35-64 years who were diagnosed with BCIS (breast carcinoma in situ) between 3/1/95 and 5/31/98 (cases); English speaking; U.S. born residents of Los Angeles County; participants in the Women's Contraceptive and Reproductive Experiences (CARE) Study and interviewed between 3/1/95 and 5/3198 (controls); owned a functional residential telephone at reference date Ex: women with prior diagnoses of BCIS or invasive breast cancer; women who had not received a mammogram within the two years before the reference date
Comment about participation selection
Strengths: analyzed BCIS in women which had increased dramatically in the two decades prior to the study reference date; one of the only studies at the time to evaluate BCIS risk factors; population based study; all cases were histologically confirmed; conducted in-person interviews; fairly high response rate amongst cases; analyzed BCIS risk by physical activity stratified by family history of breast cancer; assessed physical activity at different periods in participants' lives; quantified physical activity with MET hrs/week Limitations: few black cases; fairly limited sample size; reduced control subject pool by excluding women base on screening history; physical activity self-reported
Exposure Investigated
Exposures investigated
Physical inactivity
How exposure was measured
Questionnaire, in person
Exposure assessment comment
Physical activity self-reported
Ethnic groups with separate analysis
If this study provided a separate analysis by ethnic or racial group, the groups are listed here.
No
Confounders considered
Other breast cancer risk factors, such as family history, age at first birth, and hormone replacement therapy use, that were taken into account in the study.
Adequately controlled, confounders: age, race, income, BMI, family history of breast cancer, menopausal status, age at menopause, postmenopausal HRT use, smoking status, age at menarche, number of pregnancies
Genetic characterization included
If the study analyzed relationships between environmental factors and inherited genetic variations, this field will be marked “Yes.” “No”, if not.
No
Description of major analysis
Effect modifiers: family history of breast cancer DCIS
Strength of associations reported
Inverse association between breast cancer risk and lifetime physical activity in women with no family history of breast cancer, >4 hrs/wk vs. none, OR=0.53(0.34-0.82) trend p=0.04
Inverse association between breast cancer risk and physical activity 10 years after menarche in women with no family history of breast cancer, >4 hrs/wk vs. no activity at any age, OR=0.48(0.29-0.78) trend p=0.05
Inverse association between breast cancer risk and lifetime physical activity 10 years before reference date in women with no family history of breast cancer, >4 hrs/wk vs. no activity at any age, OR=0.43(0.26-0.69) trend p=0.01

Inverse association between breast cancer risk and physical activity 10 years before reference date >4 hrs/wk vs. no activity at any age, OR=0.52(0.33-0.80) trend p=0.03 (among exercisers only, trend p=0.13)
Inverse association between breast cancer risk and lifetime physical activity, >4 hrs/wk vs. none, OR=0.64(0.42-0.96) trend p=0.24 (among exercisers only, trend p=0.86)
Controls participation rate
Less than 70% (60%)