How Much Do Pesticides Increase Cancer Risk?

Pesticides are definitely great at killing pests.

What pests? Well, it depends on the specific pesticide, but usually they are good for killing a wide array of animals, including:

• Insects (e.g. aphids and beetles)
• Worms (e.g. root-knot nematodes)
• Molluscs (e.g. slugs and snails)
• Mammals (e.g. mice and humans)
• Etc

Now, maybe you do not care a jot for root-knot nematodes, but “humans” probably stands out in the list!

So, what pesticides are these?

They’re all pretty bad

Researchers (Dr. Tatiana Vidaurre et al.) have linked higher environmental exposure to mixtures of 31 commonly used agricultural pesticides—none individually classified by the WHO as known human carcinogens—to significantly higher rates of cancer.

As for why this happens, Dr. Vidaurre and her team say that it is most likely because these pesticides disrupt cellular processes that help maintain normal cell identity and function, particularly in the liver, potentially creating early, silent biological vulnerabilities long before cancer itself appears—by which time, for many people it can be too late.

This was based on combining six years of pesticide environmental dispersion modelling, national cancer registry data from more than 150,000 cancer patients, and molecular biology research.

In particular, the study emphasized that people are usually exposed to multiple pesticides simultaneously rather than one chemical at a time, and some highly exposed rural populations were estimated to face elevated exposure to roughly 12 pesticides at once.

This is important, because people living in rural (thus, high-exposure) regions had about a 150% increase in cancer risk compared with lower-exposure regions.

To be clear, that’s 150% increase in risk, not 150% risk.

In other words, it’s 2.5x the risk.

But, how sure are we of the link?

Well, in science, generally anything with a P-value of P < 0.05 is considered statistically significant, and in this case we see P = 2.5×10^-14

In other words, the chance of getting this result if there were no link, would be P = 0.000000000000025, which can otherwise be expressed as there being a chance of 1 in 40,000,000,000,000.

So, that’s quite conclusive!

You may be wondering: why weren’t they already established as carcinogens; are there not safety tests?

The authors argue that current safety systems—which generally assess chemicals individually—may underestimate risks from cumulative, real-world mixture exposures. A bit like we talked about in: The Most Dangerous Ingredients That Aren’t In Your Vape Device (Until You Use It)

Sometimes, it’s the combining of things that makes the most serious poison!

You can read Dr. Vidaurre’s paper here: Mapping pesticide mixtures to cancer risk at the country scale with spatial exposomics

Want to learn more?

Here’s an interesting read: Glyphosate: What Indigenous communities have suspected for years about the dangers of the herbicide

And for a much deeper dive into the broader topic of avoiding the toxins the industrial world is keen to throw our way, you might like this book that we reviewed a little while back:

Healthy Living in a Contaminated World – by Dr. Donald Hoernschemeyer

Take care!