Environment and Breast Cancer: Science Review


Evidence From Humans
 
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Occupational physical activity and the risk of breast cancer
Kruk, J.,, Aboul-Enein, H. Y. Cancer Detection and Prevention. 2003. 27, 187-192.
Topic area
Physical Activity - Body size
Study design
Other: Case-control (not population based) Cases from Cancer Registry (Stettin Province) Controls from women admitted into hospitals and clinics in the Stettin Province area
Funding agency
Not reported
Study Participants
Menopausal Status
The menopausal status of women included in this study is listed here.
Pre menopausal
Post menopausal
Number of Controls
Controls: 565
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
In: women 35-88 years of age diagnosed with breast cancer in the Stettin province (Poland) between 10/97 and 10/98 who had a radical mastectomy (cases); women age 35-93 who were admitted into hospitals and clinics in the Stettin Province area
Comment about participation selection
Strengths: analyzed breast cancer risk by occupational physical activity stratified by age; analyzed breast cancer risk by occupational physical activity in women older than 55 years stratified by BMI, fruit/vegetable intake and stress; used MET (metabolic equivalents) to categorize occupational physical activity; high participation rate amongst controls; only known study to report effect modification by stress or intake of fruits and vegetables Limitations: low participation rate amongst cases; physical activity and anthropometric data were self-reported; possible selection bias amongst cases; did not assess adolescent or recreational physical activity
Exposure Investigated
Exposures investigated
Physical inactivity
How exposure was measured
Questionnaire, self-administered
Exposure assessment comment
Physical activity 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.
No
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, BMI, age at menarche, age at first birth, number of births, duration of breast feeding, hormone use, alcohol consumption, intake of vegetables and fruits, stress and sport and recreational activities
Genetic characterization included
If the study analyzed relationships between environmental factors and inherited genetic variations, this field will be marked “Yes.” “No”, if not.
No
Description of major analysis
Effect modifiers: age, BMI, intake of fruits and vegetables, stress
Strength of associations reported
No association between breast cancer risk and occupational physical activity, >3 METs vs. <2 METs, OR=0.71(0.46-1.10) trend p<0.0001
Inverse association between breast cancer risk and occupational physical activity in women age 55 or greater, >3 METs vs. <2 METs, OR=0.40(0.20-0.81) trend p=0.001
Inverse association between breast cancer risk and occupational physical activity, >3 METs vs. <2 METs, in women age 55 or greater who have a BMI of 24 or lower, OR=0.40(0.20-0.81)
Inverse association between breast cancer risk and occupational physical activity, >3 METs vs. <2 METs, in women age 55 or greater who frequently eat fruits and vegetables, OR=0.31(0.13-0.75) trend p=0.0001
Inverse association between breast cancer risk and occupational physical activity, >3 METs vs. <2 METs, in women age 55 or greater who do not experience stress, OR=0.15(0.04-0.57) trend p=0.002
Controls participation rate
Greater than 70% (84.3%)