(Beyond Pesticides, February 23, 2017) Male pesticide applicators who experienced a pesticide spill or another related accident are more likely to harbor changes in their DNA associated with an increased risk of prostate cancer, according to a recent paper published in the journal, Environmental and Molecular Mutagenesis. While the relationship between pesticide exposure and prostate cancer is not new, this study adds to the growing body of evidence that high exposure to specific pesticides may lead to the development of prostate and other cancers. The analysis finds that after experiencing one of these exposure events, men are more likely to have higher DNA methylation of a gene linked with an increased risk of developing prostate cancer. DNA methylation is a form of gene regulation that, if disturbed, can result in gene expression changes that can cause cancer.
The researchers used data from the ongoing Agricultural Health Study (AHS), which is a long-term cohort study evaluating cancer and other health outcomes of pesticides applicators and their spouses in North Carolina and Iowa. This paper, High pesticide exposure events and DNA methylation among pesticide applicators in the agricultural health study, analyzed a sample size of 596 male pesticide applicators who underwent three phases of data collection for behavioral outcomes and pesticide exposure metrics. The participants completed a self-administered questionnaire in which they reported any high pesticide exposure events (HPEE), or “self-reported incidents of unusually high, non-specific exposure to pesticides.”
There are various mechanisms that may alter gene expression after pesticide exposure, including oxidative stress induction and endocrine disruption. These alterations and their impacts on disease development are still not clear, but, according to this study, the DNA changes and “subsequent gene inactivation has been consistently associated with prostate cancer.
Prostate cancer is the most common type of cancer among men in the U.S., after skin cancer, and, according to the American Cancer Society, is the third leading cause of cancer deaths in American men. Previous research using AHS data has identified an association between exposures to organophosphate pesticides and elevated prostate cancer risk in applicators with a family history of this specific cancer. And according to a 2013 study, “Three organophosphate insecticides were significantly associated with aggressive prostate cancer: fonofos, malathion and terbufos. The organochlorine insecticide aldrin is also associated with increased risk of aggressive prostate cancer.” Additionally, the herbicide, atrazine, is associated with an 8.4-fold increase in prostate cancer in men who work in atrazine factories and bag this toxic chemical.
The scientific literature confirms that farmworkers, their families, and their communities face elevated hazards from pesticide exposures, and existing farmworker data finds that the incidence rate of pesticide poisoning is extremely high. As a result of cumulative long-term exposures, farmworkers and their children, who often also work on the farm, are at risk of developing serious chronic health problems, such as neurological impairments, autism, cancer, and Parkinson’s disease. Other research finds that those with long-term exposure to 2,4-D have poor semen quality, and higher rates of birth defects.
Farmworkers, as usual, are on the front line of these impacts. Despite a recent important update to Worker Protection Standards, there is a need to drastically limit farmworker exposure to a wide range of toxic pesticides. Despite federal regulations to reduce pesticide exposure among farmworkers through personal protective equipment (PPE) and other measures, research conducted in farmworker communities show that such regulations are only partially enforced. High levels of pesticides continue to be detected among farmworker communities across the country, providing evidence that PPE and other controls do not go far enough to protect this highly exposed population. Ultimately, the key to making changes in the lives of farmworkers and farmworker families will be adequate enforcement of new provisions, and a transition to safer practices.
Our food choices have a direct effect on those who grow and harvest what we eat around the world. This is why certified organic food is the best choice. In addition to serious health questions linked to actual residues of toxic pesticides on the food we eat, our food buying decisions support or reject hazardous agricultural practices, and the protection of farmworkers and farm families. To learn about how buying organic food can help protect farmworkers, see Beyond Pesticides’ Eating with a Conscience guide. For more information on the impact of pesticides to farmworkers and their families, visit Beyond Pesticides’ Agricultural Justice webpage.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.