Environment and Breast Cancer: Science Review

Evidence From Humans
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Leisure-time physical activity in relation to breast cancer among young women (Washington, United States)
Chen, C.L.,, White, E.,, Malone, K.E.,, Daling, J.R. Cancer Causes and Control. 1997. 8, 77-84.
Topic area
Physical Activity - Body size
Study design
Population based case-control
Funding agency
NCI NIEHS Other: Department of Health and Human Se
Study Participants
Number of Cases
747 (invasive only) (86% pre) (12% post)
Menopausal Status
The menopausal status of women included in this study is listed here.
Pre menopausal
Post menopausal
Number of Controls
Control: 961 (88% pre) (12% post)
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
In: age 21-45 years during reference date; women diagnosed with invasive breast cancer between 1/1/1983 and 4/30/1990 in three counties of western Washington state ( King, Pierce, and Snohomish counties) (cases); white women; born in 1945 or later; speaks English; owns a telephone (controls) Ex: women with nonepithelial breast cancer; women who had a history of breast cancer; women who had Turner's disease (1 woman)
Comment about participation selection
Strengths: interviews were administered in person by trained interviewers; fairly high participation rate; analyzed breast cancer risk by weekly physical activity in different periods of life Limitations: study lacks information on physical activity between ages 21 and two years before reference date; anthropometric data and physical activity were self-reported
Exposure Investigated
Exposures investigated
Physical activity and BMI
How exposure was measured
Questionnaire, in person
Exposure assessment comment
Anthropometric data and physical activity were self-reported
Statistical Analysis
Ethnic groups with separate analysis
If this study provided a separate analysis by ethnic or racial group, the groups are listed here.
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, county of residence, age at menarche, age at first term pregnancy, parity, family history of breast cancer, BMI, education, family income, smoking status, and alcohol intake
Genetic characterization included
If the study analyzed relationships between environmental factors and inherited genetic variations, this field will be marked “Yes.” “No”, if not.
Description of major analysis
Effect modifiers: age at diagnosis, BMI, family history of bc, parity and menopausal status
Strength of associations reported
Association between breast cancer and women with a BMI of 25.56-52.57 vs 13.31-20.25, OR=0.74(0.56-0.98)
Results Comments
Findings did not support a protective effect of leisure-time physical activity in either adolescent years or in adulthood on breast cancer in young women.
Controls participation rate
Greater than 70% (78%)