- Study highlights a strong link between pregnant women exposed to DDT and breast cancer risk to their daughters.
- The findings are considered very reliable since they are based on 50-year-old blood samples.
- DDT was banned in the U.S. in 1972 but remains in use in many developing countries.
A new study published in the Journal of Clinical Endocrinology and Metabolism has found a strong link between exposure to the chemical pesticide DDT (dichlorodiphenyltrichloroethane) and cancer. The research findings, reported by NBC News, shows that women whose mothers had DDT in their blood while pregnant were almost four times more likely to develop breast cancer than their counterparts.
Results from this study are particularly reliable because 50-year-old blood samples were used to demonstrate the quantity of DDT present in the pregnant women’s systems instead of relying on one’s memory or other inaccurate measurements.
Participants in the study included Kaiser Foundation Health Plan members who received obstetric care during 1959-1967 in Alameda County, CA and their adult daughters.
Although environmental chemicals have always thought to cause breast cancer, there have only been a limited number of studies involving human subjects to support this idea until recently. According to the NBC News article, Barbara Cohn, PhD, a researcher at the Public Health Institute in Berkeley, CA and a co-author of the study noted, “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.”
Cohn’s team further went on to state, ” Many women were heavily exposed in utero during widespread DDT use in the 1960s. They are now reaching the age of heightened breast cancer risk.”
DDT was first used in the United States in 1945 to kill mosquitoes that carried malaria and other diseases. It was most heavily used in the U.S. during the 1950s and 1960s; however, it was eventually phased out and finally banned for agricultural use in the U.S. in 1972 because it was found to be deadly to birds and other wildlife. The problem was highlighted by ecologist Rachel Carson in her groundbreaking book “Silent Spring,” published in 1962. The book helped to launch the environmental movement in the U.S.
The NBC News piece acknowledges that the study does not prove that DDT causes breast cancer. The research only measured DDT levels in blood taken from the mothers of 118 women diagnosed with breast cancer and compared the levels those found in 354 women whose daughters who did not have breast cancer. It also only looked at breast cancer diagnosed in women before the age of 52. A causal link between DDT and breast cancer would have to be further tested in a larger study.
Despite the ban in the U.S., DDT is still used to fight malaria overseas in developing regions, Cohn and fellow researchers are concerned about the possible health impacts on the people there. NBC News quotes from the study: “DDT exposure persists and use continues in Africa and Asia without clear knowledge of the consequences for the next generation.”
Read the full June 16, 2015 article “DDT in Pregnancy May Raise Breast Cancer Rates in Daughters” at NBC News.