Long-banned chemical continues to kill

Fifty-three years after Rachel Carson, in her book Silent Spring, first raised concerns about the safety of the pesticide DDT, the chemical once again is in the news.

Public health researchers in California have published findings that connect maternal exposure to DDT during pregnancy to breast cancer—not in the exposed mothers but rather, 40 or 50 years later, in offspring exposed in utero. The article was published in the Journal of Clinical Endocrinology and Metabolism. In it, the authors looked at the rates of breast cancer in a group of 9,300 women born between 1959 and 1967. Of these, 118 developed breast cancer…

The authors used a well-established study approach called case-control: the 118 daughters with breast cancer (cases) were paired with 354 breast cancer-free daughters born at the same time (controls) and standard clinical variables extracted from each group. In this way, variables like race, maternal weight, lipid profiles, and breast-feeding history could be eliminated as likely causes of any difference in breast cancer rates.

By this analysis, the mothers with high rates of detectable DDT during pregnancy produced daughters who, 50+ years on, had three or four times more breast cancer than daughters of Moms with substantially lower DDT levels. A potentially very big deal for sure.

There is a large and important caveat in the analysis however. The investigators also examined the frequency of breast cancer in mothers, comparing the rate between cases and controls. Here, there was a large and very strong tilt: About 20 percent of daughters with breast cancer had a mom with the disease; in the controls, only 4 percent had a mother with breast cancer. Thus, some and perhaps most of the risk of breast cancer might be explained not by DDT exposure but genetic predisposition.

Which does not exclude DDT as an amplifying effect on genetic risk—but it does deflate some of the headline grabbing excitement the article already has claimed.

The Daily Beast further classifies divergent opinions of the results into Right vs Left instead of the fact that conservative denial is almost wholly grounded in ideology. The counterpoint being individuals and groups dedicated to science and scientific method for progress – a truly conservative style.

That the Daily Beast sees only the conflict between political entities is a reflection of their own tidy journalistic ideology. Historically, properly termed sophistry – that truth lies only safely between opposing contradictions.

3 thoughts on “Long-banned chemical continues to kill

  1. Nevermind says:

    A widely used Dow Chemical Co. weedkiller was added to a World Health Organization list of potential carcinogens, just three months after the agency made a controversial assessment of Monsanto Co.’s glyphosate herbicide.
    Based on limited evidence from laboratory animal studies and inadequate evidence in humans, 2,4-D is “possibly carcinogenic to humans,” the International Agency for Research on Cancer, a Lyon, France-based arm of the WHO, said Tuesday in a statement.
    2,4-D has been used for 70 years to control weeds in wheat, corn and soybean fields as well as gardens and lawns. The U.S. sprayed about 36 million pounds (16 million kilograms) of the chemical in 2012, according to government estimates.
    The weedkiller is a key part of Dow’s agricultural business. Dow says its new Enlist crops, which are genetically engineered to tolerate sprays of both 2,4-D and glyphosate, will help double earnings at the unit through the end of the decade. http://www.bloomberg.com/news/articles/2015-06-22/dow-chemical-weedkiller-may-cause-cancer-who-agency-says

  2. Annie says:

    “Researchers rediscover fast-acting German insecticide lost in the aftermath of WWII : Fluoridated DDT swiftly kills disease-carrying mosquitoes, which may lower its environmental impact — but its history is alarming” (New York University 10/11/19) https://www.eurekalert.org/pub_releases/2019-10/nyu-rrf101119.php
    “In his 1948 Nobel Prize address for the discovery of the insect-killing capability of DDT, Paul Müller noted that DFDT should be the insecticide of the future, given that it works more quickly than does DDT. Despite this, DFDT has largely been forgotten and was unknown to contemporary entomologists with whom the NYU researchers consulted.
    “We were surprised to discover that at the outset DDT had a competitor which lost the race because of geopolitical and economic circumstances, not to mention its connection to the German military, and not necessarily because of scientific considerations. A faster, less persistent insecticide, as is DFDT, might have changed the course of the 20th century; it forces us to imagine counterfactual science histories,” said Kahr.”

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.