Environment and Breast Cancer: Science Review

Evidence From Humans
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Risk of breast cancer following exposure to tetrachloroethylene-contaminated drinking water in Cape Cod, Massachusetts: reanalysis of a case-control study using a modified exposure assessment
Gallagher, L. G., Vieira, V. M., Ozonoff, D., Webster, T. F., Aschengrau, A. Environ Health. 2011. 10, 47.
Topic area
Environmental pollutant - Organic solvent Drinking water
Study design
Population-based case control
Funding agency
NIEHS Superfund Research Program
Study Participants
Menopausal Status
The menopausal status of women included in this study is listed here.
No analyses based on menopausal status
Number of Controls
Controls: 1,302
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
Cases and controls were permanent residents in 8 Cape Cod towns. Cases were identified from the MA Cancer Registry and were diagnosed from 1983 to 1993. Controls were demographically similar women who lived in the study area from 1983 to 1993 and were selected by random digit dialing (<64 years old), Medicare records (>65 years old), and random selection from records of MA Bureau of Health, Statistics, Research and Evaluation (deceased).
Exposure Investigated
Exposures investigated
Updated estimates for PCE exposure (cumulative relative dose delivered) between 1968 and early 1990s from improperly prepared drinking water pipes with improved water flow model and self-reported residential history. Residents of the same towns and neighb
How exposure was measured
GIS/geographic location Environmental modeling software
Exposure assessment comment
The updated exposure assessment reclassified 39% of people previously considered unexposed by Aschengrau et al. 2003 as exposed. EPANET modeling program incorporates town's water distribution systems, including location of water sources, detailed pipe characteristics, consumption nodes, timing and duration of subject's residence relative to the installation of the pipe and amount of PCE in the pipe liner, with normal ranges of flow, pressure, leaching, and demand were used to estimate exposure. Historical samples were used to validate the old, manual exposure assessment and the new, automated (EPANET) exposure assessment, and the automated exposure assessment is a more accurate model. The correlation between historical measurements and EPANET-modeled PCE concentrations had a Spearman's rank correlation coefficient of 0.65, while the manual method correlation had a Spearman rank correlation coefficient of 0.54.
Breast cancer outcome investigated
Primary incident breast cancer
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 at diagnosis, vital status at interview, family history of breast cancer, personal history of prior breast cancer, age at first birth or stillbirth, occupational PCE exposure, study of origin (from first or second study). Education, hormone use, and p
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
PCE, compared to never exposed:
>75th percentile, 0 yr latency OR 1.1 (0.9-1.5)
>90th percentile, 0 yr latency OR 1.3 (0.9-1.9)
>75th percentile, 5 yr latency OR 1.1 (0.8-1.5)
>90th percentile, 5 yr latency OR 1.4 (0.9-2.1)
>75th percentile, 9 yr latency OR 1.1 (0.8-1.5)
>90th percentile, 9 yr latency OR 1.4 (0.9-2.2)
Results Comments
ORs were slightly elevated with increasing latency periods, but no clear trend and never statistically significant.
Author address
Department of Environmental Health, Boston University School of Public Health, 715 Albany Street, Talbot 4 West, Boston, MA 02118, USA.
Controls participation rate
approximately 47%
Reviewers Comments
This is the only population-based published research on the relationship between breast cancer and solvent-contaminated drinking water. The study's strength is that it updated the methodology that was first used to assess breast cancer risk in this cohort with newer modeling technologies. A limitation of the EPANET model is the assumption that flow was constant across seasons and over a wide range of time. In validating the model with historical water samples, error may have been introduced because of volatilization of PCE, variability in water flow, or methodological error.