Environment and Breast Cancer: Science Review

Evidence From Humans
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Serum levels of polychlorinated biphenyls in Mexican women and breast cancer risk
Recio-Vega, R., Velazco-Rodriguez, V., Ocampo-Gomez, G., Hernandez-Gonzalez, S., Ruiz-Flores, P., Lopez-Marquez, F. J Appl Toxicol. 2011. 31:3, 270-8.
Topic area
Environmental pollutant - PCBs
Study design
Hospital based case-control
Funding agency
Universidad Autonoma de Coahuila Instituto Mexican
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: 70
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
Women aged 25-80 years who had lived in Comarca Lagunera, Mexico for at least one year, were identified through the Instituto Mexicano del Seguro Social gynecologic department (2 hospitals) for participation. Cases were women newly diagnosed with breast cancer who had not yet undergone chemotherapy or radiotherapy. Controls were women from the same hospitals and geographic areas but with negative biopsies.
Comment about participation selection
The time period during which cases and controls were recruited was not specified.
Exposure Investigated
Exposures investigated
20 PCB congeners in serum, grouped as follows based on Wolff et al. 1997: Potentially estrogenic (Wolff et al. 1997 group 1A): PCB 44, 52 Weak phenobarbital inducers (Wolff et al. 1997 group 1A): PCB 101, 187 Potentially antiestrogenic and dioxin-like (
Exposure assessment comment
Methods say that serum PCBs levels were calculated with a standard curve adjusted for total grams of lipid, but results are reported as ppb, so it is not clear whether results should be considered lipid-adjusted.
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.
Age, age at menarche, lactation, number of pregnancies, menopause status, total years of reproductive life, BMI, family history of breast cancer, living near an industrial facility, smoking, alcohol intake, exercise, education, organochlorine pesticide us
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
Per ppb in serum:
Potentially estrogenic: aOR 1.19 (95% CI 0.81-1.7)
PCB 101, 187 (weak phenobarbital inducers: aOR 1.40 (95% CI 0.94-2.1)
potentially antiestrogenic and dioxin-like: aOR 1.22 (95% CI 0.99-1.49)
di-ortho substituted, limited dioxin-like, persistent: aOR 1.90 (95% CI 1.25-2.88)
biologically consistent CYP1A/2B inducers: aOR 1.81 (95% CI 1.08-3.04)
environmentally relevant: aOR 1.57 (95% CI 1.20-2.07)
neurotoxic: aOR 1.30 (95% CI 0.84-2.04)
Total PCBs: aOR 1.09 (95% CI 1.02-1.16)
Results Comments
When results were stratified by menopausal status, Risks among postmenopausal women were significantly elevated with higher levels of potentially estrogenic PCBs and PCBs with limited dioxin activity, but the numbers in these analyses were small and confidence intervals were wide.
Author address
Centro de Investigacion Biomedica, Facultad de Medicina, Unidad Torreon, Universidad Autonoma de Coahuila, Mexico.
Reviewers Comments
Women with negative breast biopsies may not be an appropriate comparison group, particularly if PCB exposure is associated with benign breast changes or lesions that lead to biopsy.