Women's Exposure To Long-Banned Pesticide Has Far-Reaching Health Effects To Granddaughters: Study

Women whose grandmothers were exposed to the long-banned pesticide known as DDT were found to have higher rates of breast cancer risk factors, a new study found.

DDT (dichloro-diphenyl-trichloroethane) has been banned for around five decades, yet it appears that the pesticide still has lingering effects on the descendants of the women exposed to it. In a new study, published in the journal Cancer Epidemiology, Biomarkers & Prevention, researchers found that the granddaughters of the women who had higher DDT in their blood when they were pregnant decades ago had higher obesity rates and had their period before 11 years old.

Specifically, the granddaughters were twice as likely to have earlier menstrual periods and had two to three times the risk of obesity compared to those whose grandmothers had low DDT levels in their blood.

Both of these conditions, the researchers said, may put the granddaughters at a higher risk for breast cancer and other health conditions.

"Ancestral exposure to environmental chemicals, banned decades ago, may influence the development of earlier menarche and obesity, which are established risk factors for breast cancer and cardiometabolic diseases," the researchers wrote.

Exposure To Chemicals

DDT is a widely used pesticide before it was banned in the 1970s, Public Health Institute (PHI) said in a news release. For the Child Health and Development Studies (CHDS) project, researchers followed thousands of pregnant women and their families, starting from before DDT was banned and they continued to do so for over 60 years. Those pregnant women who gave their blood samples during their pregnancy and after giving birth are now referred to as the "founding grandmothers."

Previous CDHS studies found that the children of the founding grandmothers exposed to DDT had higher risks for obesity, breast cancer and other health issues. Now, the new study, which gathered data from 365 adult granddaughters, shows that the effects may have been passed on to the next generation as well.

All of a woman's eggs are formed during fetal development, study senior author and CHDS Director, Dr. Barbara Cohn, explained, HealthDay reported. So if the daughters of the founding grandmothers were exposed to DDT while still in the womb, their eggs might have been affected as well, which in turn affected their own children.

"These data suggest that the disruption of endocrine systems by DDT initiates in immature human eggs, decades before the eggs are fertilized," study co-lead author, Michele La Merrill of the University of California, Davis, said in the PHI news release.

"We already know that it's nearly impossible to avoid exposures to many common environmental chemicals that are endocrine disruptors," Cohn added. "Now our study shows for the first time in people that environmental chemicals like DDT may also pose health threats to our grandchildren."

The study, PHI said, is the first to show the effects of exposure to a toxic environment chemical in three generations.

There may have also been other factors that contributed to the granddaughters' risks, such as diet and other hormone-disrupting chemicals they may have been exposed to, other experts told HealthDay. But the new study, they said, adds to the understanding of whether such chemicals can contribute to obesity and other health issues.

"This isn't so much about DDT as it is about persistent organic pollutants," Sue Fenton of the U.S. National Institute of Environmental Health Sciences, which helped fund the study, said, according to the outlet.

The researchers also noted that identifying the possible effects of such "ancestral environmental exposure" may provide insight into preventing breast cancer.