New research shows women who were exposed to high levels of the pesticide DDT while in the womb are almost four times more likely to be diagnosed with breast cancer.
DDT has been banned in many countries since the 1970s, but is still commonly used in parts of Africa and Asia, the Endocrine Society reported. Many U.S. women alive today were exposed to the pesticide when it was widely used in the country during the 1960s. Pesticides such as DDT are known to interfere with the function of the hormone estrogen, and has been linked to birth defects, fertility problems, and Type 2 diabetes.
"This 54-year study is the first to provide direct evidence that chemical exposures for pregnant women may have lifelong consequences for their daughters' breast cancer risk," said one of the study's authors, Barbara A. Cohn, of the Public Health Institute. "Environmental chemicals have long been suspected causes of breast cancer, but until now, there have been few human studies to support this idea."
The researchers looked at 20,754 pregnancies among women who were members of the Kaiser Foundation Health Plan from1959 through 1967, and followed 9,300 daughters of these women for 54 years. To analyze levels of DDT exposure in utero, the researchers analyzed stored blood samples taken from the mothers during pregnancy or immediately after delivery.
The team measured DDT levels in mothers of 118 women who were diagnosed with breast cancer. The data suggests elevated levels of DDT in the mother's blood was associated with nearly a four-fold risk of breast cancer as well as a greater chance of being diagnosed with a more advanced stage of cancer.
"This study calls for a new emphasis on finding and controlling environmental causes of breast cancer that operate in the womb," Cohn said. "Our findings should prompt additional clinical and laboratory studies that can lead to prevention, early detection and treatment of DDT-associated breast cancer in the many generations of women who were exposed in the womb. We also are continuing to research other chemicals to see which may impact breast cancer risk among our study participants."
The findings were published in a recent edition of the Journal of Clinical Endocrinology & Metabolism (JCEM).
