Environment and Breast Cancer: Science Review

Evidence From Humans
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Urinary bisphenol A-glucuronide and postmenopausal breast cancer in Poland
Trabert, B., Falk, R. T., Figueroa, J. D., Graubard, B. I., Garcia-Closas, M., Lissowska, J., Peplonska, B., Fox, S. D., Brinton, L. A. Cancer Causes Control. 2014. .
Topic area
Environmental pollutant - Consumer product chemical BPA
Study design
Population based case-control
Funding agency
National Cancer Institute National Institutes of H
Study Participants
Menopausal Status
The menopausal status of women included in this study is listed here.
Analyses restricted to postmenopausal women
Number of Controls
Controls: 575
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
Participants were from the Polish Breast Cancer Study, and eligible cases consisted of women aged 20-74 who were living in Warsaw and Lodz, Poland, when they were diagnosed with invasive or 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. A subset of 575 postmenopausal cases were selected with urine samples, available tumor tissue microarray, and genetic data.
Comment about participation selection
The case ascertainment through multiple means, including a "rapid case ascertainment system" organized in the participating hospitals, provides validity as a complete population-based study. Use of the Polish population information system is a unique way to randomly select controls from the general population, making selection bias less likely. Among cases some samples were collected before treatment and/or surgery while others were collected after.
Exposure Investigated
Exposures investigated
Creatinine-adjusted conjugated urinary BPA-G from overnight 12-hour urine collected 2000-2003.
Exposure assessment comment
Urine samples for cases were collected at various times. 57% were collected before treatment, and 25% were collected before surgery. The levels of BPA-G did not significantly vary by time of collection. The authors chose to measure conjugated BPA in urine, which has been metabolized, instead of free BPA in order to limit sample contamination with BPA in collection and storage equipment. Spot urine samples do not likely represent long term exposure.
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.
Education, BMI, age at menarche, parity, years since menopause, duration of menopausal HRT, family history of breast cancer, history of benign breast disease, mammogram screening.
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
Creatinine-adjusted BPA-G levels:

Log-transformed continuous (ng/mg):
2nd quartile vs. 1st quartile: OR 1.70 (95% CI 1.15-2.52)
3rd quartile vs. 1st quartile: OR 1.02 (95% CI 0.67-1.55)
4th quartile vs. 1st quartile: OR 1.09 (95% CI 0.73-1.63)

When analysis was restricted to ER+ cancers:
Log-transformed continuous (ng/mg):
2nd quartile vs. 1st quartile: OR 1.34 (95% CI 0.83-2.17)
3rd quartile vs. 1st quartile: OR 0.86 (95% CI 0.51-1.43)
4th quartile vs. 1st quartile: OR 0.84 (95% CI 0.51-1.36)

When analysis was restricted to ER- cancers:
Log-transformed continuous (ng/mg):
2nd quartile vs. 1st quartile: OR 2.89 (95% CI 1.41-5.93)
3rd quartile vs. 1st quartile: OR 1.53 (95% CI 0.69-3.39)
4th quartile vs. 1st quartile: OR 2.11 (95% CI 0.94-4.74)
Results Comments
Because creatinine levels can vary by dietary protein, adjusting measurements for creatinine may obscure dietary exposures, such as BPA in packaged food. Sensitivity analyses on possible BPA introduction from breast cancer treatment or surgery did not substantially change ORs. This is the first study to examine BPA exposure and postmenopausal breast cancer risk.
Author address
Division of Cancer Epidemiology and Genetics, Department of Health and Human Services, National Cancer Institute, National Institutes of Health, 9609 Medical Center Drive, Room 7E-228, Bethesda, MD, 20892-9774, USA, britton.trabert@nih.gov.
Reviewers Comments
BPA-G levels were two times higher in women from Warsaw than women from Lodz. In analyses stratified by study site, Q3 and Q4 of the lower levels in Lodz appeared to be associated with odds of breast cancer, whereas the higher levels in Warsaw were not.