Environment and Breast Cancer: Science Review

Evidence From Humans
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Chlorination, chlorination by-products, and cancer: a meta-analysis
Morris, R. D., Audet, A. M., Angelillo, I. F., Chalmers, T. C., Mosteller, F. American Journal of Public Health. 1992. 82:7, 955-63.
Topic area
Environmental pollutant - Drinking water
Study design
Other: Meta-analysis
Study Participants
Menopausal Status
The menopausal status of women included in this study is listed here.
Pre menopausal
Post menopausal
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
Individual-level case-control studies meeting quality standards. 4 breast cancer reports: Young, 1981; Gottlieb, 1982; Zierfer, 1986; Wilkins, 1986
Exposure Investigated
Exposures investigated
Chlorinated drinking water assessed by surface vs. groundwater, measured chlorination level
How exposure was measured
GIS/geographic location
Exposure assessment comment
Other: See limitations in specific studies.
Statistical Analysis
Breast cancer outcome investigated
Other: see individual studies
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, gender
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
Relative risks were extracted from individual studies and combined using DerSimonian and Laird random effects model.
Strength of associations reported
Relative risk 1.18 (95% CI 0.90, 1.54) P .24
Power for detection of specified relative risk (alpha = .05):
For relative risk_______Power
1.20 .27
1.40 .69
1.60 .93
Results Comments
Of 12 studies included, only 4 included breast cancer. Power is low to detect relative risks in the range that is found for some of the established breast cancer risk factors.
Author address
Division of Biostatistics, Medical College of Wisconsin, Milwaukee 53226.