Environment and Breast Cancer: Science Review
About
Identification of occupational cancer risks in British Columbia. A population-based case-control study of 995 incident breast cancer cases by menopausal status, controlling for confounding factors
Band, P. R., Le, N. D., Fang, R., Deschamps, M., Gallagher, R. P., Yang, P. Journal of Occupational and Environmental Medicine. 2000. 42:3, 284-310.
Topic area
Environmental pollutant - Occupation
Environmental pollutant - Occupation
Study design
Other: case-control study, registry-based
Other: case-control study, registry-based
Study Participants
Number of Cases
995
995
Menopausal Status
Post menopausal
The menopausal status of women included in this study is listed here.
Pre menopausalPost menopausal
Number of Controls
Controls: 1020
Controls: 1020
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
Women under age 75 diagnosed with breast cancer in 1988-1989 identified from British Columbia cancer registry. Controls from 1989 provincial voters list, matched to cases by 5-year age group. English-speaking residents of British Columbia with no previous history of breast cancer.
Exposure Investigated
Exposures investigated
Self-reported job description, occupation and industry titles, duration and period of work. Usual occupation/industry (job longest held); ever worked in specified occupation/industry. Occupations and industries coded by Canadian Standard Occupational Cl
Self-reported job description, occupation and industry titles, duration and period of work. Usual occupation/industry (job longest held); ever worked in specified occupation/industry. Occupations and industries coded by Canadian Standard Occupational Cl
How exposure was measured
Job history
Job history
Exposure assessment comment
Agents of exposure and dose are poorly characterized, especially for white collar occupations.
Agents of exposure and dose are poorly characterized, especially for white collar occupations.
Statistical Analysis
Breast cancer outcome investigated
Primary breast cancer
Primary breast cancer
Ethnic groups with separate analysis
If this study provided a separate analysis by ethnic or racial group, the groups are listed here.
No
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.
Extensive list, but occupation is strongly tied to social position; so confounding by unknown factors may still be a problem. Healthy worker effects are also problematic.
Genetic characterization included
If the study analyzed relationships between environmental factors and inherited genetic variations, this field will be marked “Yes.” “No”, if not.
No
Description of major analysis
Conditional logistic regression for matched sets
Conditional logistic regression for matched sets
Strength of associations reported
Odds ratios are reported for many occupations for pre and post menopausal women separately and together. Excess risk is reported in various white collar administrative, teaching, etc. jobs and in jobs associated with chemical exposure.
Odds ratios are reported for many occupations for pre and post menopausal women separately and together. Excess risk is reported in various white collar administrative, teaching, etc. jobs and in jobs associated with chemical exposure.
Results Comments
Results are useful as sources of hypotheses for further study. Numbers of cases are small for many job categories, particularly for "usual" occupation. Consistency across related jobs and between "ever" and "usual" occupation are difficult to discern.
Results are useful as sources of hypotheses for further study. Numbers of cases are small for many job categories, particularly for "usual" occupation. Consistency across related jobs and between "ever" and "usual" occupation are difficult to discern.
Author address
British Columbia Cancer Agency, Vancouver, Canada.
British Columbia Cancer Agency, Vancouver, Canada.
Controls participation rate
Less than 70%
Less than 70%