Environment and Breast Cancer: Science Review

Evidence From Humans
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Pesticide exposure and risk of breast cancer: a nested case-control study of residentially stable women living on Long Island
O'Leary, E. S., Vena, J. E., Freudenheim, J. L., Brasure, J. Environmental Research. 2004. 94:2, 134-44.
Topic area
Environmental pollutant - Pesticide, GIS, Long Island
Study design
Nested case-control
Funding agency
NCI Other: Boston Komen Affiliate
Study Participants
Number of Controls
Controls: 210
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
Long Island residents diagnosed with breast cancer in 1980-1992 who were participants in the New York state cohort: residents of New York in 1980 who had resided at the same address with the same phone number for at least 18 years.
Exposure Investigated
Exposures investigated
Living on/near land that was agricultural, residence served by wells with detectable pesticides, residence within 1 mile of a hazardous waste site where pesticides were disposed
How exposure was measured
GIS/geographic location
Exposure assessment comment
Exposure measure is not subject to recall bias, which is helpful, given the low response rate. Substantial misclassification is likely. Proximity to a hazardous waste site may measure environmental exposures other than those attributable to the site.
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.
Age, race, county, education, body mass index, marital status, parity, age at first birth, alcohol, smoking
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
Living on previously agricultural land: Adjusted OR 1.5 (95% CI 0.8-2.9) (20 cases). Interaction with nulliparity or older at first birth. Women 26+ at first birth who lived on previously agricultural land compared with women with first birth before age 26 and living on never agricultural land: OR 6.4 (2.2-18.2) [14 cases/7 controls].
Residence in a water district with a well with detected pesticides: No association
Residence within one mile of a hazardous waste site containing pesticides: Adjusted OR 1.5 (95% CI 0.5-4.3) (12 cases). No association in a continuous model.
Results Comments
Nonresponse may be a source of bias. Several important breast cancer risk factors were not controlled. Long-term residents are not representative of Long Island women.
Author address
Department of Preventive Medicine, Stony Brook University, Stony Brook, NY 11794-8036, USA. eoleary@notes.cc.sunysb.edu