When Rachel Carson’s “Silent Spring” first raises alarm about DDT and its devastating effects on birds and fish, we begin to understand how this pesticide affects humans. Chemicals can take years to manifest their treacherous power, and scientists have been working together for decades – study for study – the reasons why DDT still haunts us.
First, it was breast cancer in women who were exposed to this hormone-disrupting drug in the 1950s and ’60s. Then came their daughters, who were exposed in the womb. Over the years, researchers have also linked DDT exposure to obesity, birth defects, reduced fertility and testicular cancer in boys.
Now, a team of toxicologists, molecular biologists and epidemiologists at UC Davis and the Public Health Institute in Oakland have confirmed for the first time that granddaughters of women exposed to DDT during pregnancy also suffer from serious health threats: higher obesity and menstrual periods that precede the age of 11 begins.
Both factors, scientists believe, could put these young women at greater risk for breast cancer, as well as high blood pressure, diabetes and other diseases.
“This is further proof that a pregnant woman and her baby are not only vulnerable to the chemicals she is exposed to, but also her future grandchild,” said Barbara Cohn, director of the Institute for Health and Health Development. and Public Health Development, said. research project in California that has followed more than 15,000 pregnant women and their families since 1959.
“This is something that people have always thought possible,” she said, “but there has never been a human study to support the existence of the link.”
The findings come at a time of renewed public interest in DDT, a problem largely contained in a faded chapter of history. Concerns have grown since The Times reported last fall that the country’s largest producer of DDT had once dumped as much as half a million barrels of its waste into the deep ocean.
The pesticide, which has now been banned, is so stable that it still poisons the environment and moves up the food chain. Significant amounts of DDT-related compounds are still accumulating in Southern California dolphins, and a recent study linked the presence of these persistent chemicals to an aggressive cancer in sea lions.
As far as people are concerned, ‘there is a clear line you can trace what is happening’, said Linda Birnbaum, who, as the former director of the National Institute of Environmental Health Sciences and the National Toxicology Program, followed these multigenerational studies with great interest. .
“A lot of people want to think that the problems with DDT have gone away because Congress banned them in 1972. Well, they did not,” said Birnbaum, who is now a residence student at Duke University. “By the time the daughters became pregnant with the granddaughters, it was long after DDT was banned – and yet they bore the seeds of these problems.”
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More than 60 years ago, in the heyday of DDT, a team of scientists had the foresight to start collecting blood samples from more than 15,000 pregnant women at Kaiser Permanente Hospital in Oakland. Every woman and also shortly after giving birth every woman gave a sample that was studied and carefully archived.
Researchers tested the blood for DDT and its related contaminants and continued to follow up on health assessments. They kept in touch with the female daughters, who were exposed to DDT in the womb, and thereafter with their granddaughters.
An airplane dusted DDT powder in a herd of sheep in Medford, Ore., In 1948. DDT was once considered a miracle killer.
(Associated Press)
They found after years of research that women who were heavily exposed to DDT during childhood were five times more likely to develop breast cancer, and that exposure to a mother to DDT during pregnancy, or immediately after birth, was linked to an increased risk of breast cancer for their daughter. Their daughters are also more likely to experience delays with getting pregnant.
In this most recent study, published on Wednesday in the journal Cancer Epidemiology, Biomarkers & Prevention, the research team found that the risk of obesity in the granddaughters – who are now in their twenties and thirties – was two to three times greater than women whose grandmothers had little DDT in their blood during pregnancy. These granddaughters also had twice as many menstrual periods – another indication of increased health risks later in life.
This persistent exposure to generations is likely related to the reproductive system, Cohn said. Since a female is born with all her eggs, a granddaughter is also exposed to DDT if her mother is exposed in the womb.
“Even though we banned things more than 40 years ago, people walking on earth now – the granddaughters of the pregnant people – are exposed,” Cohn said. She wonders if the increasing amount of childhood cancer, diabetes and other health problems affecting young people today is also somehow related to these chemicals of the past. “This is the full meaning of what a ‘forever chemical’ is – in some ways, what makes any chemical possible ‘forever’ if it has the potential to do so.”
Bruce Blumberg, a professor of developmental and cell biology at UC Irvine, still remembers the trucks that used to inject massive amounts of DDT into farms and neighborhoods. At the supermarket where he worked as a child, foggers are brought in at the end of each day.
“The whole market would be full of DDT mist,” said Blumberg, who also teaches pharmaceutical sciences. “The industry wants you to believe that chemicals have no effect, because the doses are too low and there are no effects, and they are all crazy alarmists.”
Blumberg now specializes in studying how chemicals in the environment can affect our genes and expose people to obesity, affecting about 42% of Americans today. He does laboratory experiments on mice to answer the many questions that scientists could not test on humans.
That is why the multigenerational Bay Area study, to which he is not affiliated, is so important, he said. It provides much-needed human observation data that is incredibly difficult to obtain – perhaps even more difficult to maintain.
‘If we are happy, the group is [of Bay Area women] will continue through four, five, six generations, ‘he said,’ and we will really learn something about the effects of what has happened in the past on the future. ‘
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Akilah Shahid said she was shocked, yet fascinated, to learn that she was in the third generation of a major study on how chemicals in the environment can affect women.
A biology major at Mills College, Shahid, said it all clicked for her when she researched the research. Her family was no stranger to health problems. Her grandmother alone has fought cancer three times already.
“I feel like cancer has come out of nowhere for a while,” she said. “You do not know who is going to get it, and now we have a reason why.”
Akilah Shahid is a third-generation participant in the Public Health Institute’s Child Health and Development Studies Research Program.
(Thanks to Liv Schultheis)
Shahid, now 30, practices a lot. She tries to eat well. It empowers her to know that her weight is not entirely her fault – and that there is just so much within her control.
DDT is no longer allowed, but she can not help but wonder about all the other chemicals that still exist today – bisphenol A (BPA), per- and polyfluoroalkyls (PFAS) and other manufactured compounds that seem to never work away. She avoids plastic water bottles and tries to be mindful of how her choices and actions can currently expose her future grandchildren to an unknown disease.
‘How many times have we talked about climate change and things we should do better for our children and grandchildren? This is another proof that hello, what we are doing today is going to further influence people, ‘she said.
“I hope this is a wake-up call for many people, because we are talking about saving the environment for our future generations again today.”