Environment and Breast Cancer: Science Review

Evidence From Humans
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Cancer mortality and occupational exposure to aromatic amines and inhalable aerosols in rubber tire manufacturing in Poland
de Vocht, F., Sobala, W., Wilczynska, U., Kromhout, H., Szeszenia-Dabrowska, N., Peplonska, B. Cancer Epidemiol. 2009. 33:2, 94-102.
Topic area
Environmental pollutant - Occupation
Study design
Retrospective cohort
Funding agency
European Union 6th Framework Programme’s Environ
Study Participants
Menopausal Status
The menopausal status of women included in this study is listed here.
No analyses by menopausal status
Number in Cohort
Cohort: 6,054
Cohort participation rate
Follow-up data was available for 97% of the cohort
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
The cohort includes 6,054 women who had been employed for at least 3 months in a rubber tire manufacturing factory in Poland between 1950 and 1995. Deaths were identified through company HR records or Polish Electronic System of Population Evidence for those no longer employed at the plant.
Comment about participation selection
Women stayed at a given occupational career for 10-12 years on average, with 11% of women employed for <1 year. Causes of death were unknown for 12% of deaths in cohort, due to a strike of Polish medical doctors (1997/1998) and regulation changes in Poland (2002).
Exposure Investigated
Exposures investigated
Factory exposures to aromatic amines and inhalable aerosols
How exposure was measured
Job history Population-specific job exposure matrix
Exposure assessment comment
Authors note average cumulative exposure for women in this cohort was up to five times higher than for men. Authors note this is because on average, women were employed for longer than men and in different departments.
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 (based on birth year quartiles). Estimates for aromatic amines adjusted for inhalable aerosol exposure, and vice versa.
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
Female breast cancer mortality by exposure to aromatic amines, compared to lowest tertile of exposure:
Tertile II vs. tertile I: RR 3.69 (95% CI 0.60-22.55)
Tertile III vs. tertile I: RR 5.83 (95% CI 0.44-86.97)
Tertile IV vs. tertile I: RR 10.40 (95% CI 0.32-339.2)

Female breast cancer mortality, compared to lowest tertile of exposure to inhalable aerosol:
Tertile II vs. tertile I: RR 0.24 (95% CI 0.02-2.59)
Tertile IV vs. tertile I: RR 0.16 (95% CI 0.01-4.45)
Results Comments
JEMs also estimated exposure to rubber fumes, however authors noted that cumulative exposures to rubber fumes and aromatic aerosols were highly correlated (Pearson correlation coefficient = 0.86) so they did not attempt to assess exposure to rubber fumes independent of aromatic aerosols. Wide 95% CIs were likely due to small number of female breast cancer cases.
Author address
School of Translational Medicine, Faculty of Medical and Human Sciences, The University of Manchester, Manchester, UK. frank.devocht@manchester.ac.uk
Reviewers Comments
Breast cancer mortality is not a sensitive measure of breast cancer risk. A strength of this study is its use of factory workers as a comparison group, rather than using the general population.