Environment and Breast Cancer: Science Review

Evidence From Humans
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Occupational exposure to organic solvents and breast cancer in women
Peplonska, B., Stewart, P., Szeszenia-Dabrowska, N., Lissowska, J., Brinton, L. A., Gromiec, J. P., Brzeznicki, S., Yang, R., Sherman, M., Garcia-Closas, M., Blair, A. Occup Environ Med. 2010. .
Topic area
Environmental pollutant - Occupation Organic Solvents
Study design
Population based case-control
Study Participants
Menopausal Status
The menopausal status of women included in this study is listed here.
Stratified analysis based on menopausal status
Number of Controls
Controls: 2,502
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
Eligible cases for the Polish Breast Cancer Case-Control study were women aged 20-74 living in Warsaw and Lodz, Poland when they were diagnosed with invasive and in situ breast cancer between 2000-2003. Cases were identified through hospitals and cancer registries. Controls were randomly selected using the Polish Electronic System of Population Evidence, matched by city of residence and in 5-yr age groups. Three women with missing information on family history of breast cancer were excluded from the analysis.
Comment about participation selection
The study employed a rapid case ascertainment system at the hospitals, which can help to improve representation of those with more aggressive cancer, who might not survive long after diagnosis.
Exposure Investigated
Exposures investigated
Occupational exposure to organic solvents in general and benzene in particular assessed by industrial hygienists based on job history data from in-person interviews. The reviewers were blinded to the case-control status. Four exposure indices were evaluat
How exposure was measured
Job history Questionnaire, in person
Exposure assessment comment
The term 'organic solvents' encompassed aromatic, aliphatic, and chlorinated solvents, ketones, organic acid esters, and petroleum distillates, but not carbon disulfide. The broad categorization of "organic solvent" exposure may have contributed to substantial variation in duration and intensity of exposure to job-related chemicals within the 'exposed' category. The authors propose that recall bias is unlikely because there has been little public attention in Poland about organic solvents and breast cancer risk, suggesting that any exposure misclassification would be non-differential.
Breast cancer outcome investigated
Primary incident breast cancer
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.
Study site, age, education, age at menarche, menopausal status, age at menopause, age at first full-term pregnancy, number of full-term pregnancies, breastfeeding, BMI, family history, mammography, and alcohol use.
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
Total organic solvent exposure, compared to never exposed:

Premenopausal women, high cumulative exposure: aOR 1.57 (95% CI 0.99-2.5)
Alcohol abstinents, ever exposed: aOR 1.22 (95% CI 1.0-1.5)
Alcohol consumers, ever exposed: aOR 1.11 (95% CI 0.9-1.4)

Duration of total organic solvent exposure, compared to never exposed:

>0-5 yrs aOR 1.17 (95% CI 0.9-1.5)
>5-10 yrs aOR 1.27 (95% CI 0.9-1.8)
>10 yrs aOR 1.13 (95% CI 0.9-1.4)

>0-5 yrs aOR 0.77 (95% CI 0.5-1.2)
>5-10 yrs aOR 1.97 (95% CI 1.1-3.7)
>10 yrs aOR 1.43 (95% CI 0.9-2.2)

>0-5 yrs aOR 1.45 (95% CI 0.98-2.1)
>5-10 yrs aOR 1.17 (95% CI 0.7-2.0)
>10 yrs aOR 1.46 (95% CI 1.1-2.0)

>0-5 yrs aOR 1.06 (95% CI 0.6-1.8)
>5-10 yrs aOR 1.71 (95% CI 1.0-3.1)
>10 yrs aOR 1.23 (95% CI 0.8-1.8)

>0-5 yrs aOR 0.99 (95% CI 0.7-1.4)
>5-10 yrs aOR 1.14 (95% CI 0.7-1.8)
>10 yrs aOR 0.90 (95% CI 0.7-1.2)

Benzene exposure, compared to never exposed:
Ever exposed: aOR 1.00 (95% CI 0.8-1.3)
Low cumulative exposure: aOR 1.00 (95% CI 0.7-1.5)
High cumulative exposure: aOR 0.99 (95% CI 0.7-1.4)
Results Comments
The authors note that estimated intensity of exposure among women in their study was low. No significant trend for duration of exposure to organic solvents in postmenopausal women (p for heterogeneity in trends between pre- and postmenopausal = 0.012). Results were stratified by alcohol consumption because alcohol, an organic solvent, may modify the observed effect of exposure. Women with missing covariate data (161) were included in analysis as separate "unknown" category for the relevant variables.
Author address
Department of Occupational and Environmental Epidemiology, Nofer Institute of Occupational Medicine, Poland;
Reviewers Comments
General population, including both workers and non-workers, may not be an appropriate comparison group.