Environment and Breast Cancer: Science Review

Evidence From Humans
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Occurrence of breast cancer in relation to recreational exercise in women age 50-64 years
McTiernan, A.,, Stanford, J. L.,, Weiss, N. S.,, Daling, J. R.,, Voigt, L. F. Epidemiology. 1996. 7, 598-604.
Topic area
Physical Activity
Study design
Population based case-control
Study Participants
Number of Cases
537 (44 pre) (493 post)
Menopausal Status
The menopausal status of women included in this study is listed here.
Pre menopausal
Post menopausal
Number of Controls
Controls: 492 (47 pre) (445 post)
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
In: white women age 50-64 diagnosed with histologically confirmed invasive or in-situ breast cancer between 1/88 and 6/90 (cases); resident of King County, WA; owned a telephone; spoke English Ex: did not speak English; did not own a phone; women with a previous diagnosis of breast cancer; nonwhite women
Comment about participation selection
Strengths: large population based study of women age 50-64 years of age; fairly good participation rate; conducted in-person interviews; analyzed information on physical activity in two period of life; analyzed association between breast cancer and physical activity through weekly duration of exercise, energy expenditure, and weekly duration of high intensity exercise Limitations: only analyzes recreational physical activity
Exposures investigated
Sedentary lifestyle
How exposure was measured
Questionnaire, in person
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.
Age and education
Genetic characterization included
If the study analyzed relationships between environmental factors and inherited genetic variations, this field will be marked “Yes.” “No”, if not.
Strength of associations reported
Inverse association between breast cancer risk and postmenopausal women age 55 and older who exercised on average more than 5 hours/wk in adulthood vs. no activity, OR=0.8(0.5-1.3) trend p=0.03 (ORs hover around 1.0 )
Inverse association between breast cancer risk and postmenopausal women age 55 and older who engaged in high intensity exercises on average 3 hours/wk or more in adulthood vs. no activity, OR=0.6(0.3-0.9) trend p=0.03
Results Comments
Overall a weak negative association between physical activity and breast cancer risk in middle-aged women.
Controls participation rate
Greater than 70% (73.0%)