Exposure to glyphosate, the active ingredient in Monsanto’s Roundup weed killer, could increase the risk of cancer by much as 41%, according to new research conducted at the University of Washington in St. Louis, Missouri.
“Our analysis focused on providing the best possible answer to the question of whether or not glyphosate is carcinogenic,” senior author Lianne Sheppard said in a statement issued earlier this week. “As a result of this research, I am even more convinced that it is.”
Sheppard and her team analyzed six epidemiological studies involving glyphosate published between 2001 and 2018. While the review centered around human studies, the research team also considered the evidence from laboratory animals.
By focusing on the most highly exposed groups in each study, they determined that exposure to glyphosate may increase the risk of non-Hodgkin’s lymphoma by as much as 41%.
While that suggests a much greater link between glyphosate and cancer than previously thought, the findings are in line with an earlier review conducted by the World Health Organization’s International Research on Cancer (IARC).
“This research provides the most up-to-date analysis of glyphosate and its link with Non-Hodgkin Lymphoma, incorporating a 2018 study of more than 54,000 people who work as licensed pesticide applicators,” said co-author Rachel Shaffer.
The study authors did acknowledge that their research was limited by several factors, including a relatively small number of available glyphosate studies. There was also an imbalance in the way the studies were designed, as five were case-control and one was a cohort study.
There were also important differences in the comparison group utilized in each of the studies; some used the lowest exposure group as the reference, while others used the unexposed group.
And finally, none of the analyzed studies accounted for the increase in glyphosate use that followed the introduction of “green-burn-down” – the practice of spraying the herbicide on crops just before they’re harvested — in the mid-2000s.
[The report] highlights the need for new, well-designed and robust studies at appropriate exposure levels,” Francis Martin, a biosciences professor at the University of Central Lancashire, told CNN. “The number of robust studies in the literature examining this question is pathetically small.”
Monsanto’s Roundup is the most popular weed killer in the world.
However, the product has been the subject of controversy since IARC declared glyphosate a “probable human carcinogen” in March 2015. Monsanto categorically rejected that designation, and worked aggressively to discredit the IARC review.
Bayer, which acquired Monsanto last year, continued on that track yesterday, calling this latest analysis a “statistical manipulation” that suffered from “serious statistical flaws.”
Unfortunately for Bayer, the new findings won’t go unnoticed by thousands of plaintiffs in the United States who claim Monsanto Roundup caused their cancer.
In August, the San Francisco Superior Court jury convened for the nation’s first Roundup cancer trial awarded $289 million to a California groundskeeper suffering from terminal non-Hodgkin’s lymphoma. Although the presiding judge ultimately cut the verdict to $78 million, she upheld the jury’s finding that glyphosate caused the plaintiff’s cancer.
Bayer faces a second trial later this month in the U.S. District Court, Northern District of California.
With more than 10,000 Monsanto Roundup lawsuits currently pending in courts throughout the United States, one analyst recently told Bloomberg News that Bayer could face liability of roughly $680 million in connection with the litigation.