Environment and Breast Cancer: Science Review

Evidence From Humans
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Polychlorinated biphenyls and breast cancer: A congener-specific meta-analysis
Leng, L., Li, J., Luo, X. M., Kim, J. Y., Li, Y. M., Guo, X. M., Chen, X., Yang, Q. Y., Li, G., Tang, N. J. Environ Int. 2016. 88, 133-41.
Topic area
Environmental pollutant - PCBs
Study design
Funding agency
National Natural Science Foundation of China Minis
Study Participants
Number of Cases
Not reported
Menopausal Status
The menopausal status of women included in this study is listed here.
No analysis based on menopausal status
Number of Controls
Not reported
Country where study was conducted
This meta-analysis was conducted in China and revi
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
16 studies with plasma/adipose PCB congener measurements and breast cancer outcomes published until 2015. Results were reported for 9 congeners that were measured by at least 2 studies.
Exposures investigated
Pooled OR/RRs were calculated with highest vs. lowest exposure measures extracted from studies, along with covariates, time of sample collection, and other study details, and are unitless. PCBs were grouped according to the following categories: potentia
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.
Confounders assessed vary across the original studies, but studies were rated based on confounders considered.
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
Potentially estrogenic:
PCB 187: OR 1.18 (95% CI 1.01-1.39)

Anti-estrogenic, dioxin-like:
PCB 118: OR 1.32 (95% CI 0.98-1.78)
PCB 138: OR 1.08 (95% CI 0.99-1.17)
PCB 156: OR 1.19 (95% CI 0.85-1.67)
PCB 170: OR 1.28 (95% CI 0.89-1.86)

CYP inducers:
PCB 99: OR 1.36 (95% CI 1.02-1.80)
PCB 153: OR 1.04 (95% CI 0.81-1.34)
PCB 180: OR 1.02 (95% CI 0.81-1.29)
PCB 183: OR 1.56 (95% CI 1.25-1.95)
Results Comments
PCB concentrations assigned to dose-response reference groups were not uniform across studies.
Author address
Department of Occupational and Environmental Health, School of Public Health, Tianjin Medical University, Tianjin 300070, China. Department of Toxicology, School of Public Health, Tianjin Medical University, Tianjin 300070, China. Department of Biomedical
Reviewers Comments
Statistically significant positive associations were observed with PCB 187, PCB 99, PCB 183 exposures, which may indicate importance of CYP induction. PCB 187 is typically grouped as potentially estrogenic, but has also shown CYP2B induction.