Study Finds Some Pesticides Carry Cancer Risks Similar to Smoking

Researchers found that non-Hodgkin’s lymphoma cancer risks were 154% higher among those exposed to pesticides than for those who smoke.

Exposure to pesticides is associated with an increased risk of cancer that is comparable to, or even greater than, the risk posed by smoking cigarettes, according to the findings of a new study.

In a report published in the journal Frontiers in Cancer Control and Society on July 24, researchers from Rocky Vista University College of Osteopathic Medicine, led by Isain Zapata, indicate that pesticide exposure in different geographical regions of the U.S. appears to increase an individual’s risk of developing several different types of blood and organ cancers.

While exposure to pesticides is known to a major concern among those in the agricultural workforce, the findings suggest that the threat extends beyond these individuals, impacting individuals living in certain areas as well. According to the Environmental Working Group’s Shoppers Guide to Pesticides in Produce, nearly 75% of all non-organic produce sold in the U.S. is contaminated with harmful pesticides, and many consumers are routinely exposed to the chemicals on a daily basis.

Research published in 2023 in the journal JAMA Network Open revealed that exposure to some pesticides increases the risk of heart disease, finding organochlorine pesticides can increase the risk of stroke and heart attack by more than 70%.

Pesticides and Cancer Risks

Zapata’s research team analyzed exposures to 69 common pesticides, utilizing data from the United States Geological Survey to conduct an ecological study.

This study modeled cancer rates based on exposure levels and regional locations, helping to identify broader trends without definitively proving a cause-and-effect relationship between the two factors, finding that exposure to a combination of pesticides carries a risk of cancer higher than if the participants smoked cigarettes.

The researchers included data on pesticides such as glyphosate, which is widely used on most consumer produce, usually under the brand name Roundup, as well as atrazine, boscalid, dimethomorph, dicamba, and dinotefuran. According to the findings, pesticide exposure was linked to an increased risk of non-Hodgkins’s lymphoma, leukemia, colon, lung, pancreatic, and bladder cancer.

Data indicated cases of non-Hodgkin’s lymphoma cancer were 154% higher due to pesticide exposure than smoking. Leukemia cancer cases linked to pesticides were 21% higher than cases due to smoking, and bladder cancer had 19% more cases of cancer due to pesticides than smoking cigarettes.

The risk of pesticide-linked cancer was the highest in agriculturally rich areas of the United States, like the Midwest. Researchers determined the risk was greater because most agricultural areas use a combination of many different pesticides to treat crops and produce when farming.

Researchers said the combination of the exposure to different pesticides raises the odds of nearby residents developing cancer. This is especially true since, in the real world outside of research, most people will be exposed to more than one source of pesticides.

They recommend a holistic approach to preventing greater exposure to pesticides by establishing intervention programs to help reduce exposure from all sources. They also warned that establishing future policies to help reduce exposure levels are needed.

Roundup Exposure Lawsuits

One of the pesticides mentioned in the study, Roundup, has been widely used for decades in the agricultural industry, as well as for residential purposes as a weed killer, containing glyphosate as the active ingredient. Although it has been marketed as safe for humans, there is now growing research highlighting serious health concerns for users.

In 2015, the World Health Organization’s International Agency for Research on Cancer (IARC), classified glyphosate as a probable cancer-causing agent. Since then, a number of restrictions have been imposed on Roundup use in various parts of the world, due to concerns of an increased risk of non-Hodgkin’s lymphoma and other cancers linked to the weed killer’s use.

As a result of the failure to warn about the potential side effects of glyphosate, Bayer and its Monsanto subsidiary have faced more than 120,000 Roundup lawsuits over the past decade, each raising similar allegations that users developed non-Hodgkin’s lymphoma from the weed killer, either when using the product in an agricultural setting or around the home.

Although Bayer and it’s Monsanto unit have paid more than $10 billion in Roundup settlements for failing to warn about the risk of non-Hodgkin’s lymphoma, the manufacturers continue face about 50,000 lawsuits throughout the U.S. court system, and new claims continue to be filed as former users of the weed killer develop the blood cancer.

To limit liability from the Roundup failure to warn lawsuits, Bayer has announced that it will remove the active ingredient glyphosate from Roundup consumer products, while keeping the formulation for large agricultural users. However, as former users develop cancer, it is still expected that Bayer will face a steady stream of new lawsuits for years to come.