Environment and Breast Cancer: Science Review

Evidence From Humans
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Organophosphate insecticide use and cancer incidence among spouses of pesticide applicators in the Agricultural Health Study
Lerro, C. C., Koutros, S., Andreotti, G., Friesen, M. C., Alavanja, M. C., Blair, A., Hoppin, J. A., Sandler, D. P., Lubin, J. H., Ma, X., Zhang, Y., Beane Freeman, L. E. Occup Environ Med. 2015. .
Topic area
Environmental pollutant - Pesticides Organophosphate pesticides
Study design
Prospective case control
Funding agency
Study Participants
Menopausal Status
The menopausal status of women included in this study is listed here.
Analyses stratified by menopausal status
Number of Controls
Controls: 29,325
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
1,059 cases/29,325 cancer free female spouses of private pesticide applicators living in Iowa and North Carolina with complete OP data, enrolled in the Agricultural Health Study between 1993-1997 and followed until 2011 (Iowa) and 2010 (North Carolina). Cases identified by linkage to Iowa and North Carolina state cancer registries.
Exposure Investigated
Exposures investigated
Self-reported use of 50 pesticides, including 10 OP pesticides: chlorpyrifos, coumaphos, diazinon, dichlorvos, fonofos, malathion, parathion, phorate, terbufos, and trichlorfon at baseline.
Exposure assessment comment
Participants were asked to recall lifetime pesticide use and prompted for specific pesticides. The reliability of the questionnaire administered to their spouses (applicators) was previously determined to be 70%->90%.
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, state of residence, cigarette pack-years smoked, race, alcohol use, education, BMI, family history of cancer, whether participant treats home or lawn for pests, ever use of specific pesticides, menopausal status, number of live births, ever use of or
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
Compared never use of OP insecticides:

Among all women:
Any OP insecticide: RR 1.20 (95% CI 1.01-1.43)
Chlorpyrifos: RR 1.41 (95% CI 1.00-1.99)
Diazinon RR 1.14 (95% CI 0.93-1.38)
Terbufos RR 1.52 (95% CI 0.97-2.36)

When analysis was restricted to ER-/PR- cases:
Chlorpyrifos: RR 2.26 (95% CI 1.07-4.75)

Among postmenopausal women:
Any OP insecticide: RR 1.27 (95% CI 1.00-1.62)
Results Comments
In an analysis limiting cases to those diagnosed more than 5 years after enrollment, no significantly increased risks were noted. OR for ever vs never use of any OP insecticides was 1.02 (95% CI 0.77-1.36) among premenopausal women. No significant findings for individual OP insecticides when analyses were stratified by menopausal status. No other OP insecticides, showed significant associations with a particular tumor subtype.
Author address
Occupational and Environmental Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, Maryland, USA Yale University School of Public Health, New Haven, Connecticut, USA. Occupational and Environmental Epide