Glyphosate is a broad-spectrum systemic herbicide and crop desiccant. It is an organophosphorus compound, specifically a phosphonate, which acts by inhibiting the plant enzyme 5-enolpyruvylshikimate-3-phosphate synthase.
It is the most widely used broad-spectrum systemic herbicide in the world. Recent evaluations of the carcinogenic potential of glyphosate-based herbicides (GBHs) by various regional, national, and international agencies have engendered controversy.
In a new study, scientists at the University of Washington investigated whether there was an association between high cumulative exposures to GBHs and increased risk of non-Hodgkin lymphoma (NHL) in humans. The outcomes suggest that exposure increases the risk of some cancers by more than 40 percent.
Scientists conducted an updated meta-analysis — a comprehensive review of existing literature — and focused on the most highly exposed groups in each study. They found that the link between glyphosate and non-Hodgkin lymphoma is stronger than previously reported.
Senior author Lianne Sheppard, a professor in the UW Department of Environmental & Occupational Health Sciences and Biostatistics, said, “Our analysis focused on providing the best possible answer to the question of whether or not glyphosate is carcinogenic. As a result of this research, I am even more convinced that it is.”
Scientists examined the epidemiologic studies published between 2001 and 2018 and determined the exposure to glyphosate may increase the risk of non-Hodgkin lymphoma by as much as 41 percent.
Co-author Rachel Shaffer, a UW doctoral student in the Department of Environmental & Occupational Health Sciences said, “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.”
Researchers say more studies are needed to account for the effects of increased exposure from green burndown, which may not be fully captured in the existing studies reviewed in this new publication.
Funding was provided by the National Institutes of Environmental Health Sciences award T32ES015459 and the University of Washington Retirement Association Aging Fellowship.
Their findings were published this month in the online journal Mutation Research/Reviews in Mutation Research.