Environment and Breast Cancer: Science Review

Evidence From Humans
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Lifetime physical activity and breast cancer risk in the Shanghai Breast Cancer Study
Matthews, C.E.,, Shu, X.O.,, Jin, F.,, Dai, Q.,, Herbert, J.R.,, Ruan, Z.X.,, Gao, Y.T.,, Zheng, W. British Journal of Cancer. 2001. 84:7, 994-1001.
Topic area
Physical Activity
Study design
Population based case-control
Study Participants
Number of Cases
1,459 (956 pre) (503 post)
Menopausal Status
The menopausal status of women included in this study is listed here.
Pre menopausal
Post menopausal
Number of Controls
Controls: 1,556 (993 pre) (563 post)
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
In: women diagnosed with breast cancer between 8/96 and 3/98 (cases); permanent resident of urban Shanghai; age 25-64 years; no prior history of cancer; alive at the time of interview Ex: refused to participate; died before interview
Comment about participation selection
Strengths: conducted in-person interviews; large case-control study with many cases; population based study; cases were confirmed by two senior pathologists; high participation rate; one of the first studies to analyze breast cancer risk by physical activity in adolescence and in adulthood independently as well as changes over time; examined breast cancer risk by physical activity stratified by menopausal status Limitations: possible recall bias; possible selection bias due to the nature of case-control studies; cases were interviewed after diagnosis which might have altered their results
Exposures investigated
Sedentary lifestyle
How exposure was measured
Questionnaire, in person
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, education, household income, family history of breast cancer, history of breast fibroadenoma, age at menarche, age at first live birth and age at menopause
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: menopausal status
Strength of associations reported
Inverse association between breast cancer risk and adolescent physical activity of 4.30+ hrs/day vs. no exercise, OR=0.52(0.39-0.70)
Inverse association between breast cancer risk and adult physical activity of 1.92+ hrs/day vs. no exercise, OR=0.40(0.27-0.59)
Inverse association between premenopausal breast cancer risk and lifetime physical activity (adolescence and adult) vs. no lifetime exercise, OR=0.57(0.40-0.82)
Inverse association between postmenopausal breast cancer risk and lifetime physical activity (adolescence and adult) vs. no lifetime exercise, OR=0.36(0.24-0.55)
Controls participation rate
Greater than 70% (90.3%)