After I posted this article, the….Genetic Literacy Project pointed me to Geoffrey Kabat’s piece about the Zhang et al. [glyphosate-cancer] study. Kabat did a deep dive into the studies that Zhang et al.’s work is based on and uncovered a critical flaw in the study, one that I hadn’t found. More than half of the “weight” of the meta-analysis by Zhang, and by far the largest number of cancer cases, come from a single study by Andreotti et al. published in 2018. That study reported risks for 4 different time points: 5, 10, 15, and 20 years.
It turns out, as Kabat reports, that only the 20-year period showed any increase in risk of cancer. The relative risks of cancer at 5, 10, and 15 years were actually lower in the group exposed to glyphosphate, and yet Zhang et al. didn’t mention this fact.
Now, no one thinks that glyphosphate lowers the risk of cancer, but Zhang et al. did not report that they had cherry-picked in this way. At a minimum, they should have reported what their findings would be if they used the other time periods. I suspect that they’d have found no increased risk of cancer–but this wouldn’t make for such a catchy headline. This omission on their part is a serious flaw, indicating that they (and their results) might have been unscientifically biased.
The bottom line: even in those with very high exposures to glyphosphate, the evidence that it causes any type of cancer is very weak. And for ordinary consumers, there’s nothing to worry about.
Read full, original article: Does The Herbicide RoundUp® Cause Cancer?