This summary table contains detailed information about research studies. Summary tables offer an informative look at the science behind many breast cancer guidelines and recommendations. However, they should be viewed with some caution. In order to read and interpret research tables successfully, it is important to understand some key concepts. Learn how to read a research table.
Introduction: Although it has long been suggested that exposure to environmental pollutants might increase the risk of breast cancer, most studies have not found a link.
Some of the most common and well-studied environmental pollutants are organochlorines. Organochlorines include:
A good way to assess exposure to organochlorines is to measure the levels of these chemicals in a person’s blood. The results of most studies that have measured blood levels of DDE and PCBs, including the Long Island Breast Cancer Study, have found no link between increased levels of these chemicals and breast cancer risk .
Learn more about organochlorines and breast cancer risk.
Learn more about the environment and breast cancer risk.
Learn about the strengths and weaknesses of different types of studies.
See how this risk factor compares with other risk factors for breast cancer.
Read our perspective on pesticides and breast cancer risk (November 2010).*
Read our perspective on cancer cluster studies of pesticides and breast cancer risk (November 2011).*
* Please note, the information provided within Komen Perspectives articles is only current as of the date of posting. Therefore, some information may be out of date at this time.
Study selection criteria: Nested case-control studies with at least 150 breast cancer cases and pooled analyses. Table note: Relative risk above 1 indicates increased risk. Relative risk below 1 indicates decreased risk.
Study Population(number of participants)
Relative Risk of Breast Cancer in Women with the Highest Blood Levels of DDE Compared to Those with the Lowest, RR (95% CI)
Relative Risk of Breast Cancerin Women with the Highest Blood Levels of PCBs Compared to Those with the Lowest, RR (95% CI)
Nested case-control studies
Millikan et al. 
Raaschou-Nielsen et al. 
Laden et al. 
Helzlsouer et al. 
Hoyer et al. [6,7]
Krieger et al. 
Ward et al. 
Lopez-Cervantes et al. 
Laden et al. 
NS = No statistically significant increase or decrease in risk
† Similarly, when results examined by hormone receptor status, there was no statistically significant increase or decrease in risk for either hormone receptor-positive or hormone receptor negative breast cancers.
1. Gammon MD, Wolff MS, Neugut AI, et al. Environmental toxins and breast cancer on Long Island. II. Organochlorine compound levels in blood. Cancer Epidemiol Biomarkers Prev. 11(8):686-97, 2002.
2. Millikan R, De Voto E, Duell EJ, et al. Dichlorophenyldichloroethene, polychlorinated biphenyls, and breast cancer among African-American and white women in North Carolina. Cancer Epidemiol Biomarkers Prev. 9:1233-1240, 2000.
3. Raaschou-Nielsen O, Pavuk M, LeBlanc A, et al. Adipose organochlorine concentrations and risk of breast cancer among postmenopausal Danish women. Cancer Epidemiol Biomarkers Prev. 14(1):67-74, 2005.
4. Laden F, Hankinson SE, Wolff MS, et al. Plasma organochlorine levels and the risk of breast cancer: an extended follow-up in the Nurses' Health Study. Int J Cancer. 91(4):568-74, 2001.
5. Helzlsouer KJ, Alberg AJ, Huang HY, et al. Serum concentrations of organochlorine compounds and the subsequent development of breast cancer. Cancer Epidemiol Biomarkers Prev. 8(6):525-32, 1999.
6. Hoyer AP, Grandjean P, Jorgensen T, et al. Organochlorine exposure and risk of breast cancer. Lancet. 352(9143):1816-20, 1998.
7. Hoyer AP, Jorgensen T, Rank F, and Grandjean P. Organochlorine exposures influence on breast cancer risk and survival according to estrogen receptor status: a Danish cohort-nested case-control study. BMC Cancer. 1(1):8, 2001.
8. Krieger N, Wolff MS, Hiatt RA, et al. Breast cancer and serum organochlorines: a prospective study among white, black, and Asian women. J Natl Cancer Inst. 86(8):589-99, 1994.
9. Ward EM, Schulte P, Grajewski B, et al. Serum organochlorine levels and breast cancer: a nested case-control study of Norwegian women. Cancer Epidemiol Biomarkers Prev. 9(12):1357-67, 2000.
10. Lopez-Cervantes M, Torres-Sanchez L, Tobias A, Lopez-Carrillo L. Dichlorodiphenyldichloroethane burden and breast cancer risk: a meta-analysis of the epidemiologic evidence. Environ Health Perspect. 112(2):207-14, 2004.
11. Laden F, Collman G, Iwamoto K, et al. 1,1-Dichloro-2,2-bis(p-chlorophenyl)ethylene and polychlorinated biphenyls and breast cancer: combined analysis of five U.S. studies. J Natl Cancer Inst. 93(10):768-76, 2001.
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