Environment and Breast Cancer: Science Review

Evidence From Humans
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Occupational exposures and female breast cancer mortality in the United States
Cantor, K. P., Stewart, P. A., Brinton, L. A., Dosemeci, M. Journal of Occupational and Environmental Medicine. 1995. 37:3, 336-48.
Topic area
Environmental pollutant - Occupation, PAH, solvents, PCBs, styrene
Study design
Other: Case-control study, mortality follow-up
Study Participants
Menopausal Status
The menopausal status of women included in this study is listed here.
Pre menopausal
Post menopausal
Number of Controls
Controls: 117,794
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
Mortality records from 1984-1989 from 24 states, homemakers excluded.
Exposure Investigated
Exposures investigated
Probability and level of 31 exposures, based on usual occupation on death certificates.
Exposure assessment comment
Jobs involve multiple correlated chemical exposures. Usual job is nonspecific resulting in substantial misclassification due to amount of time spent at the job and specific job characteristics. However, the effort to link jobs to chemicals, rather than using job titles, is helpful in generating hypotheses.
Statistical Analysis
Breast cancer outcome investigated
Mortality from breast cancer
Ethnic groups with separate analysis
If this study provided a separate analysis by ethnic or racial group, the groups are listed here.
African Americans
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, socioeconomic status based on job. Confounders not adequately controlled.
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, Gart method.
Strength of associations reported
Styrene: association among both blacks and white and for both level and probability of exposure.
Exposure level (0-3) excluding women with low probability of exposure: adjusted OR (* if confidence interval excludes one)
Blacks by exposure group:
1: 2.14*
2: 1.36
Whites, by exposure group
1: 1.21*
2: 1.18*
3: 1.20
Excess risk in metalworking
Little evidence of higher risk from exposure from diesel and gasoline exhaust, PAHs, PCBs, insecticides. ORs significantly below one for PAH.
Little evidence of higher risk for solvents as a group, but some evidence for specific solvents: methylene chloride, carbon tetrachloride, formaldehyde.
Tables provide additional useful detail.
Results Comments
Exposed jobs may be more physically demanding, causing "healthy worker" effects in comparisons with other jobs and confounding of breast cancer risk by physical activity. Both of these effects would likely result in lower odds ratios for exposed jobs. OR estimates generally increase when adjusted for SES.
Author address
Environmental Epidemiology Branch, National Cancer Institute, Bethesda, Maryland 20892, USA.