DDT hasn't been used in the United States since the 70's but this alarming new study reveals a little-known link between exposure and one of the most deadly forms of cancer.
DDT was banned in the US in 1972. Although it was used originally as a pesticide, its negative effects on human health spawned the modern environmental movement, inspiring Rachel Carson to write her famous “Silent Spring.” According to the Washington Post, the chemical has already been linked to birth defects, miscarriage, and lowered fertility.
The EPA has classified DDT as a “probable” carcinogen, but its effects on cancer development is still relatively unknown. There have only been a handful of studies examining the link, and most of them were conducted during the peak of its use in the 1950s. According to a 2014 meta-analysis of these studies, however, there was no significant connection between exposure and breast cancer.
Unfortunately, the meta-analysis may have failed to take one important factor into account – genetics.
A new study published on Tuesday in the Journal of Clinical Endocrinology and Metabolism found that there was in fact a link between DDT and breast cancer, but the risk had been passed on to the daughters of mothers that had been exposed.
The study followed the daughters of women who participated in a study that spanned from 1959 to 1967, when DDT was used widely and accumulated in the fat, milk, butter, and other products made from the animals we eat. It was even included in some wallpapers.
There were 9,300 daughters born to the participants of the study over that time. By examining the levels of DDT in the blood when each mother gave birth, doctors were able to determine with startling accuracy which of their daughters would develop breast cancer later on in life.
They found that heightened levels of DDT in the blood led to an almost four-fold increase in the daughter’s risk of developing breast cancer, regardless of whether or not her mother had ever had it.
DDT is still used in the developing world, especially in Africa and Asia. The study’s authors hope their work will help nations make good policy decisions after considering the shocking new information about DDT and its associated risks.