Environment and Breast Cancer: Science Review

Evidence From Humans
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Occupational exposure to methylene chloride and risk of cancer: a meta-analysis
Liu, T., Xu, Q. E., Zhang, C. H., Zhang, P. Cancer Causes Control. 2013. 24:12, 2037-49.
Topic area
Environmental pollutant - Organic solvents
Study design
Funding agency
Not reported
Study Participants
Number of Cases
Not reported
Menopausal Status
The menopausal status of women included in this study is listed here.
No analyses based on menopausal status
Number of Controls
Not reported
Country where study was conducted
The meta-analysis reviewed studies published in th
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
The meta analysis included 3 articles through 2012 with results from case-control or cohort studies that reported on methylene chloride and breast cancer, out of a total of 18 eligible articles about methylene chloride and cancer.
Exposure Investigated
Exposures investigated
Exposure measures in the three studies included: (1) Employment records for cohort of workers exposed to methylene chloride compared to general population (2) Probability and level of methylene chloride exposure from a job exposure matrix (3) Ever vs neve
Exposure assessment comment
Self-reported job exposure was used to assess methylene chloride exposure in two studies while job exposure matrices were used for analysis in the third study.
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.
Varied from none to age, race, SES
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
Overall combined OR: OR 1.02 (95% CI 0.48-2.16)

OR by study design:
Case-control (1 study): OR 0.80 (95% CI 0.78-0.83)
Cohort (2 studies): OR 1.23 (95% CI 0.29-5.15)
Author address
Department of Occupational Health, Huzhou Center for Disease Control and Prevention, 999 Changxing Rd, Huzhou, 313000, Zhejiang Province, China.
Reviewers Comments
Authors note that none of the original studies adjusted analyses for known risk factors for breast cancer, including age at menarche, age at menopause, age at first birth, history of benign breast disease, and family history of breast cancer.