Environment and Breast Cancer: Science Review

Evidence From Humans
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Physical activity and breast cancer risk in women aged 20-54 years
Verloop, J.,, Rookus, M. S.,, Van Der Kooy, K.,, Van Leeuwen, F. E. Journal of the National Cancer Institute. 2000. 92:2, 128-135.
Topic area
Physical Activity - Body size
Study design
Population based case-control
Funding agency
Other: Dutch Cancer Society
Study Participants
Number of Cases
918 (invasive only)
Menopausal Status
The menopausal status of women included in this study is listed here.
Pre menopausal
Post menopausal
Number of Controls
Control: 918
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
In: women age 20 to 54 who participated in the Netherlands Oral Contraceptives and Breast Cancer Study; resident of one of four regions (Amsterdam, West, East and Eindhoven); diagnosed with invasive breast cancer from 1986 to 1989 (cases)
Comment about participation selection
Strengths: large population based case-control study; analyzed breast cancer risk by physical activity during different stages of life; assessed occupational physical activity and breast cancer risk; information was obtained by trained interviewers in the subject's home; both members of the matched pair were interviewed by the same person; one of the few studies to analyze breast cancer risk by lifetime physical activity Limitations: low participation rate amongst cases; physical activity levels amongst nonrespondents was not assessed; few post women in study; physical activity levels and anthropometric data were self-reported; possible differential and nondifferential misclassification; occupational physical activity was limited to the title of the occupation; possible selection bias since nonrespondents tended to have less healthy lifestyles
Exposure Investigated
Exposures investigated
Physical activity and BMI
How exposure was measured
Questionnaire, self-administered
Exposure assessment comment
Physical activity levels and anthropometric data were self-reported
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: family history of breast cancer, education, smoking status, occupational activity, recreational physical activity, benign breast disease, and parity
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: BMI, family history of breast cancer, benign breast disease, parity
Strength of associations reported
Inverse association between breast cancer risk and girls who were more active at age 10-12 compared to less active girls at the same age, OR=0.68(0.49-0.94)
Inverse association between breast cancer risk and women who were involved in lifetime recreational physical activity, OR=0.70(0.56-0.88)
Inverse association between breast cancer risk and women who were involved in recreational and moderate occupational physical activity, OR=0.58(0.42-0.82)
Inverse association between breast cancer risk and women who were involved in lifetime recreational physical activity who had a BMI of <21.8, OR=0.57(0.40-0.82)