Background
In modern agriculture practices, pesticides are essential to ensure high enough crop yields and food security. However, the chemicals may adversely affect plant and animal life as well as the individuals exposed to them.
“We accept that an [individual] who is not a farmer living in a community with heavy agricultural production is exposed to many of the pesticides used in their vicinity. It becomes part of their environment,” explained senior study author Isain Zapata, PhD, Associate Professor at the Rocky Vista University College of Osteopathic Medicine in Colorado.
Study Methods and Results
In a population-based, nationwide study, researchers evaluated the risk of cancer following exposure to agricultural pesticides. They placed pesticide use into context with smoking, a known cancer risk factor.
“It is difficult to explain the magnitude of an issue without presenting any context, so we incorporated smoking data. We were surprised to see estimates in similar ranges,” Dr. Zapata stated.
The researchers found that in environments with heavy agricultural production, the impact of pesticide use on cancer incidence rivaled that of smoking. The strongest association was among non-Hodgkin lymphoma, leukemia, and urothelial carcinoma—in which the effects of pesticide exposure were more pronounced than the effects of smoking.
The researchers noted that because pesticides aren’t used one at a time, it may be more likely that their combination can have an impact on the risk of cancer. As a result, they included 69 pesticides for which usage data are available via the U.S. Geological Survey.
“We present a list of major pesticide contributors for some specific cancers, but we highlight strongly that it is the combination of all of them and not just a single one that matters,” Dr. Zapata indicated. “In the real world, it is not likely that [individuals] are exposed to a single pesticide, but more to a cocktail of pesticides within their region,” he added.
Although the findings extended the knowledge of pesticide use in the United States, the researchers underlined that cancer risk factors are often complicated, and assessing the larger picture may not reflect individual outcomes. For instance, geography often has a strong impact. In regions where more crops are grown—such as the Midwest—the associations between pesticide use and cancer incidence were more striking.
Conclusions
The researchers hope to encourage more individuals, including those who are not frequently exposed to such chemicals, to consider the potential risks posed by pesticide use. “In our study, we found that for some cancers, the effect of agricultural pesticide usage is comparable in magnitude to the effect of smoking,” emphasized Dr. Zapata.
