Environment and Breast Cancer: Science Review

Evidence From Humans
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Cancer mortality in workers exposed to chlorophenoxy herbicides and chlorophenols
Saracci, R., Kogevinas, M., Bertazzi, P. A., Bueno de Mesquita, B. H., Coggon, D., Green, L. M., Kauppinen, T., L'Abbe, K. A., Littorin, M., Lynge, E., et al., Lancet. 1991. 338:8774, 1027-32.
Topic area
Environmental pollutant - Dioxins, TCDD, chlorophenoxy herbicides, chlorophe
Study design
Cohort mortality follow up
Study Participants
Menopausal Status
The menopausal status of women included in this study is listed here.
Pre menopausal
Post menopausal
Number in Cohort
Cohort: 18,390 (1,537 females)
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
Chemical production workers or sprayers from ten countries in the International Register of Workers Exposed to Phenoxy Herbicides and their Contaminants, excluding those who died before 1955. Compared with national death rates
Exposure Investigated
Exposures investigated
Worked with dioxins, TCDD, chlorophenoxy herbicides, chlorophenols. Categories: Exposed (13,482 workers) , probably exposed, exposure not known, not exposed. Duration of exposure used to allocate person-years at risk.
Exposure assessment comment
Categories are broad, resulting in misclassification. Exposure involves multiple chemicals that cannot be separated.
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.
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, sex, calendar period. 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
Average follow-up 17 years. Standardized mortality ratio, Poisson regression
Strength of associations reported
Exposed males 345 (42-1246), 2 deaths
Exposed females 30 (1-166), 1 death
Results Comments
Only 10 female deaths were observed. Number of women in the cohort is comparatively small; their age is not reported.
Author address
Unit of Analytical Epidemiology, International Agency for Research on Cancer, Lyon, France.