Environment and Breast Cancer: Science Review

Evidence From Humans
Print this page
Breast cancer among former college athletes compared to non-athletes: a 15-year follow-up
Wyshak, G.,, Frisch, R.E. British Journal of Cancer. 2000. 82:3, 726-730.
Topic area
Physical Activity
Study design
Retrospective cohort
Funding agency
Other: Advanced Medical Research Foundation and Ha
Study Participants
Number of Cases
175 (64 athletes) (111 non-athletes)
Menopausal Status
The menopausal status of women included in this study is listed here.
Pre menopausal
Post menopausal
Number in Cohort
Cohort: 3940 (1945 athletes) (1995 non-athletes) (93% postmenopausal)
Cohort participation rate
Retention/participation exceeded 70% for exposed a
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
In: college alumnae who completed a health history questionnaire between 1981 and 1982 and a second questionnaire between 1996 and 1997; roughly half of the questionnaires were sent to former college athletes Ex: women who died before they completed the second questionnaire; women with incomplete responses to questionnaires; women lost to follow-up; women who reported breast cancer in the first questionnaire
Comment about participation selection
Strengths: lengthy 15 year follow-up; one of the first to investigate the relation between physical activity and breast cancer in a retrospective cohort study; study confirms previously reported findings that breast cancer risk is significantly lower among former college athletes; the two major comparison groups (athletes and non-athletes) met rigorously defined criteria for physical activity in college, high school and earlier; women who reported being former athletes were identified from college athletic department records; study procedures minimized recall bias and the risk of misclassification; athletes and non-athletes did not differ significantly in BMI; analyzed breast cancer risk by physical activity among former athletes and non-athletes stratified by age Limitations: obtained information through mailed questionnaires; few reported cases; vast majority of participants were postmenopausal during the second questionnaire; did not stratify results by menopausal status; did not exclude women with prior cancers; retrospective cohort study; did not stratify physical activity by type of sport played
Exposure Investigated
Exposures investigated
Lack of physical activity in non athletes, athletes were identified by athletic department records
How exposure was measured
Questionnaire, self-administered
Exposure assessment comment
Did not stratify physical activity by type of sport played
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, ever-pregnant, use of contraceptive; HRT use; family history of breast cancer; current exercise; smoking status; % body fat
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 under 45 Follow-up: 15 years
Strength of associations reported
Inverse association between breast cancer risk and physical activity among women of all ages, OR=0.605(0.438-0.835)