Environment and Breast Cancer: Science Review

Evidence From Humans
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Tetrachloroethylene-contaminated drinking water and the risk of breast cancer
Aschengrau, A., Paulu, C., Ozonoff, D. Environ Health Perspect. 1998. 106 Suppl 4, 947-53.
Topic area
Environmental pollutant - Organic solvent
Study design
Population based case-control
Funding agency
Other: Superfund Basic Research Program
Study Participants
Menopausal Status
The menopausal status of women included in this study is listed here.
Pre menopausal
Post menopausal
Number of Controls
Controls: 686
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
Upper Cape Cancer Study participants: Incident cancers diagnosed 1983-1986 among permanent Upper Cape Cod residents; controls from Medicare beneficiaries (aged 65+) and random-dialing (< 65); living and proxies for deceased
Exposure Investigated
Exposures investigated
"Relative delivered dose" measured as estimated mass (milligrams) of PCE-contaminated drinking water entering the home during specified years based on engineering model of water distribution system. Ordinal estimate. Self-reported residence history.
How exposure was measured
Questionnaire, by telephone GIS/geographic location Other: Environmental model
Exposure assessment comment
Unvalidated model. Ever/never drank bottled water and bathing habits are considered, but volume of water consumed and exposure by inhalation are not well measured.
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.
Confounders were extensively controlled.
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
Logistic regression with no and up to 13 years latency. Some analyses restricted to women who never drank bottled water regularly and postmenopausal women.
Strength of associations reported
Exposure categorized as > zero, < median, > median, > 75th percentile, >90th percentile.
When 7 and 9 years of latency were taken into account, adjusted relative risks were 1.5 (95% CI 0.5-4.7) and 2.3 (95% CI 0.6-8.8) among women with exposure >75th percentile, and 2.7 (95% CI 0.4-15.8) and 7.6 (95% CI 0.9-161.3) for women > 90th percentile. Numbers are small for longer latency and subgroup analyses. Few differences seen in subgroup analyses, but some higher relative risks were reported for postmenopausal women.
We conducted a population-based case-control study to evaluate the relationship between cases of breast cancer and exposure to tetrachloroethylene (PCE) from public drinking water ( n = 258 cases and 686 controls). Women were exposed to PCE when it leached from the vinyl lining of water distribution pipes. The relative delivered dose was estimated using an algorithm that accounted for residential history, water flow, and pipe characteristics. Only small increases in breast cancer risk were seen among ever-exposed women either when latency was ignored or when 5 to 15 years of latency was considered. No or small increases were seen among highly exposed women either when latency was ignored or when 5 years of latency was considered. However, the adjusted odds ratios (ORs) were more increased for highly exposed women when 7 and 9 years of latency, respectively, were considered (OR 1.5 95% CI 0.5-4.7 and OR 2.3, 95% CI 0.6-8.8 for the 75th percentile, and OR 2.7, 95% CI 0.4-15.8 and OR 7.6, 95% CI 0.9-161.3 for the 90th percentile). The number of highly exposed women was too small for meaningful analysis when more years of latency were considered. Because firm conclusions from these data are limited, we recently undertook a new study with a large number of more recently diagnosed cases.
Author address
Department of Epidemiology, University School of Public Health, Boston, Massachusetts, USA. aaschen@bu.edu