Environment and Breast Cancer: Science Review

Evidence From Humans
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Early-life physical activity and postmenopausal breast cancer: effect of body size and weight change
Shoff, S. M., Newcomb, P. A., Trentham-Dietz, A., Remington, P. L., Mittendorf, R., Greenberg, E. R., Willett, W. C. Cancer Epidemiology, Biomarkers & Prevention. 2000. 9:6, 591-5.
Topic area
Physical Activity - Body size
Study design
Population based case-control
Study Participants
Number of Cases
4,614 (invasive only)
Menopausal Status
The menopausal status of women included in this study is listed here.
Post menopausal
Number of Controls
Control: 5,817
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
In: female residents of Wisconsin, Massachusetts, Maine and New Hampshire; diagnosed with breast cancer between April 1988 and December 1991 (cases); women with listed telephone numbers and drivers' licenses (if less than 65 years); with no personal history of breast cancer (controls); postmenopausal Ex: women who died; could not be located; refused to participate; women with incomplete information on physical activity, menopausal status, weight or height
Comment about participation selection
Strengths: large population based case control study; analyzed breast cancer risk in post women by physical activity and BMI and weight change; one of the only studies to evaluate the association between physical activity during late adolescence/young adulthood and risk of postmenopausal breast cancer and how it differs according to early-life body size and subsequent weight change; analyzed the interaction between BMI at age 18 and weight change from 18 to date of diagnosis by physical activity Limitations: anthropometric and previous physical activity data self-reported; low participation rate; physical activity was limited to a single point in time
Exposure Investigated
Exposures investigated
BMI, weight change and sedentary life-style
How exposure was measured
Questionnaire, by telephone
Exposure assessment comment
Anthropometric and previous physical activity data 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: BMI at age 18, age at first full-term pregnancy, parity, age at menarche, family history of breast cancer, education, age at menopause and physical activity
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
Interactions: physical activity
Strength of associations reported
Inverse association between breast cancer risk and psychical activity (>364 days/year vs 0 days/year), OR=0.55(0.39-0.78) p trend=0.002
Association between breast cancer risk and recent BMI (>26.5 vs <21.8) OR=1.33(1.18-1.49)
Association between breast cancer risk and weight change (>15 kg vs 0-7.3 kg) OR=1.40(1.26-1.56)
Women who lost weight since age 18 and who exercised more than 364 days/year vs 0 days/year had a decrease in breast cancer risk, OR=0.19(0.05-0.70)
Results Comments
The interaction between strenuous physical activity and post breast cancer risk varied according to BMI at age 18 No interaction between strenuous physical activity and post breast cancer risk according to recent BMI
Author address
University of Wisconsin Comprehensive Cancer Center, Madison 53706, USA.
Controls participation rate
Less than 70% (51%)