Women exposed to the organochlorine DDE are at increased risk of developing breast cancer, say researchers in Canada and Mexico.
In a study of 246 women, researchers found that blood levels of DDE were higher among breast cancer cases compared with controls. All of the study women had given birth to at least one healthy child and, even after adjusting for several factors, including breastfeeding, higher levels of DDE were associated with a more than double the risk of developing breast cancer compared with those women with the lowest exposure to the chemical.
The increased risk was more pronounced among postmenopausal women. Prolonged breastfeeding was shown to provide a slight decrease in the risk of breast cancer, independent of DDE levels. In this study, blood levels of DDT, unusually, did not appear to affect the risk of developing breast cancer (Am J Epidemiol, 2000; 152: 363-70).