Environment and Breast Cancer: Science Review

Evidence From Humans
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Case-control study of PCBs, other organochlorines and breast cancer in Eastern Slovakia
Pavuk, M., Cerhan, J. R., Lynch, C. F., Kocan, A., Petrik, J., Chovancova, J. J Expo Anal Environ Epidemiol. 2003. 13:4, 267-75.
Topic area
Environmental pollutant - Pesticide, organochlorine, PCB, DDT, DDE, hexachlo
Study design
Hospital based case-control
Funding agency
Study Participants
Menopausal Status
The menopausal status of women included in this study is listed here.
Pre menopausal
Post menopausal
Number of Controls
Controls: 88
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
Cases were histologically confirmed breast cancer cases diagnosed between May 1997 and May 1999. Controls were women from the same district, recruited through a network of primary care physicians.
Exposure Investigated
Exposures investigated
Lipid-corrected serum concentrations of 15 PCB congeners, p,p'-DDE, p,p'-DDT, and hexachlorobenzene (HCB)
Exposure assessment comment
Blood samples were taken after surgical treatment of the breast cancer.
Ethnic groups with separate analysis
If this study provided a separate analysis by ethnic or racial group, the groups are listed here.
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
Analysis of covariance to compare means of log-transformed serum levels, with age as a continuous covariate. Unconditional logistic regression to estimate odds-ratios for breast cancer, adjusting for age, height, BMI, number of full-term pregnancies, men
Strength of associations reported
Age-adjusted levels of DDT and DDE were significantly higher in cases than in controls.

PCB congeners were classified into group 1 (28, 52, 101), group 2 (105, 114, 118, 123, 156, 157, 167, 189), and group 3 (138, 153, 170, 180). Age-adjusted levels of group 2 and 3 PCBs did not differ significantly between cases and controls. Group 1 congeners were significantly lower among cases.

The risk of breast cancer decreased with increasing levels of PCBs for all three groups, but the trend was only significant in group 1.

The highest tertile of DDE exposure was non-significantly increased (OR = 3.04, 95% CI: 0.65-14.3). However when DDE was modelled as a log-transformed continuous indicator variable, the association was statistically significant (OR = 2.41, 95%CI: 1.04-5.58).

No differences in results were seen when analysis was limited to postmenopausal women only.
Results Comments
All participants were residents for at least 10 years in the Michalovske district of Slovakia, which is heavily contaminated with PCBs. Cases and controls were not matched on age. Numbers were limited (24 cases). Results for individual PCB congeners were not presented, and levels of several congeners were not measured (including 126, 169, 81, 37, 183, 187)
Author address
University of Texas School of Public Health, Regional Campus, 5323 Harry Hines Boulevard, V8.112M, Dallas, Texas 75235-9128, USA. Marian.Pavuk@UTSouthwestern.edu