Environment and Breast Cancer: Science Review

Evidence From Humans
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Association between residence on Cape Cod, Massachusetts, and breast cancer
McKelvey, W., Brody, J. G., Aschengrau, A., Swartz, C. H. Ann Epidemiol. 2004. 14:2, 89-94.
Topic area
Environmental pollutant
Study design
Population based case-control
Funding agency
Other: Massachusetts Department of Public Health
Study Participants
Menopausal Status
The menopausal status of women included in this study is listed here.
Pre menopausal
Post menopausal
Number of Controls
Controls: 992
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
Cape Cod Breast Cancer and Environment Study participants: permanent residents of Cape Cod diagnosed with breast cancer in 1988-1995 and controls
Exposure Investigated
Exposures investigated
Years of residence on Cape Cod, Massachusetts
How exposure was measured
GIS/geographic location
Exposure assessment comment
Residence on Cape Cod is not linked to specific environmental exposures. Many women were exposed to possible environmental risk factors in other geographic locations before moving to Cape Cod.
Statistical Analysis
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.
Extensively taken into account
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
Unconditional logistic regression
Strength of associations reported
Breast cancer risk was elevated for women living on Cape Cod for five or more years compared to fewer years. The trend to increasing risk with increasing residence on Cape Cod was statistically significant (p = 0.02), but increasing risk was not monotonic. Highest risk was for women living on the Cape 25 to less than 30 years (Adjusted OR=1.72; 95% CI 1.12-2.64).
Results Comments
Higher risk on Cape Cod that is not explained by established breast cancer risk factors or mammography use supports the hypothesis of an unknown, perhaps environmental, factor.
Author address
Silent Spring Institute, Newton, MA 02458, USA. mckelvey@silentspring.com