Environment and Breast Cancer: Science Review

Evidence From Humans
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Polychlorinated biphenyls, cytochrome P450 1A1, and breast cancer risk in the Nurses' Health Study
Laden, F., Ishibe, N., Hankinson, S. E., Wolff, M. S., Gertig, D. M., Hunter, D. J., Kelsey, K. T. Cancer Epidemiology, Biomarkers and Prevention. 2002. 11:12, 1560-5.
Topic area
Environmental pollutant - Organochlorine, PCB, Genetic variability
Study design
Nested case-control
Study Participants
Menopausal Status
The menopausal status of women included in this study is listed here.
Pre menopausal
Post menopausal
Number of Controls
Controls: 367
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
Women in the Nurses' Health Study. Cases were pathologically confirmed, incident breast cancers. Non-cancer controls were matched to cases based on year of birth, menopausal status, month and time of blood collection, fasting status at blood draw, and postmenopausal hormone use.
Exposures investigated
Lipid-adjusted serum PCB levels were assessed; allele frequencies of CYP1A1 variant m1 and m2 (CYP1A1-m2 polymorphism), used modified PCR/restriction digestion assay
How exposure was measured
Biological Questionnaire, self-administered
Ethnic groups with separate analysis
If this study provided a separate analysis by ethnic or racial group, the groups are listed here.
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.
Family history of breast cancer, history of BBD, age at menarche, BMI, number of children and age at first birth, duration of lactation.
Genetic characterization included
If the study analyzed relationships between environmental factors and inherited genetic variations, this field will be marked “Yes.” “No”, if not.
Description of major analysis
Conditional logistic regression analysis. Analyses were stratified by menopausal status. Logistic regression analysis of CYP1A1 frequencies and cancer risk, including effect modification by PCB level.
Strength of associations reported
An elevated breast cancer risk was seen among women with high PCB levels and with the CYP1A1-m2 variant (multivariate OR = 2.78, 95% CI: 0.99-7.82), compared to wildtype genotype and lowest tertile of PCB.
Among all women with variant type m2 and highest tertile of total PCB, ARR=1.39 (0.60-3.12).
No association between m1 type and BC risk.
Author address
Channing Laboratory, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA. francine.laden@channing.harvard.edu