Environment and Breast Cancer: Science Review

Evidence From Humans
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Occupational histories of cancer patients in a Canadian cancer treatment center and the generated hypothesis regarding breast cancer and farming
Brophy, J. T., Keith, M. M., Gorey, K. M., Laukkanen, E., Hellyer, D., Watterson, A., Reinhartz, A., Gilberston, M. Int J Occup Environ Health. 2002. 8:4, 346-53.
Topic area
Environmental pollutant - Pesticide
Study design
case-control, hospital-based
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: 237
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
Cases diagnosed with breast cancer and controls with other cancers, excluding lymphoma
Comment about participation selection
Controls with cancer are not representative of the population. Other cancers may be causally related to pesticides, reducing the opportunity to find an association for breast cancer.
Exposure Investigated
Exposures investigated
Ever engaged in farming
How exposure was measured
Job history Questionnaire - self-administered
Exposure assessment comment
Level of exposure is not known. Specific chemicals cannot be identified.
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.
SES based on residence at diagnosis
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
Odds ratio calculated with logistic regression
Strength of associations reported
Age adjusted OR all ages 1.34 (0.81-2.34)
< 55 OR 2.57 (0.75-8.55)
> 55 OR 1.18 (0.66-2.13)
For younger women, the OR is strengthened by adjusting for education or income. Age and education-adjusted OR 9.05 (1.06-77.43)
Results Comments
Control for confounding is inadequate, controls may be at higher risk than a general population, results are statistically unstable.
Author address
Department of Sociology and Anthropology, University of Windsor, Ontario, Canada. jimbrophy@sympatico.ca