(Beyond Pesticides, January 24, 2024) A study published in Environmental Sciences Europe finds that 2,4-D, pyrethroid (PRY), and organophosphate (OP) pesticides increase the risk of cancer through oxidative stress (OS). The study highlights that pesticides that increase cancer risk also raise inflammation biomarkers that indicate damage to organs (e.g., liver) via oxidative stress. Additionally, different cancers show different sensitivities to pesticides; thus, cancer risk changes with exposure concentration and pattern. Despite a plethora of studies linking cancer and pesticide exposure, very few cover the mechanisms involved in cancer development, including OS.
Only five to ten percent of cancers are hereditary. However, environmental or lifestyle factors, like chemical exposure, can make an individual more susceptible to cancer development through gene mutation. In fact, a vast amalgamation of research links cancer risk to pesticide exposure, which augments the risk of developing both common and rare cancers. Therefore, studies like this highlight the importance of understanding how pesticide use can increase the risk of latent diseases, which do not readily develop upon initial exposure.
Using data from the National Health and Nutrition Examination Survey (NHANES), researchers investigated the link between the risk of several cancers and pesticide exposure. The researchers also thoroughly evaluated the mechanism’s impact on cancer development and oxidative stress. The study focuses on six types of cancers: breast, colon, cervical, prostate, melanoma, and non-melanoma skin cancer. Individuals who have cancer were the case group, while individuals without cancer were the control. To determine pesticide exposure, researchers measured the concentration of pesticide metabolites in urine, with the most detectable being used in the study, including metabolites of OPs (oxypyrimidine [diazinon], paranitrophenol [parathion], and dichlorovnl-dimeth prop carboacid [dichlorvos]), pyrethroids (4-fluoro-3-phenoxybenzoic acid, 3-phenoxybenzoic acid), and 2,4-D. From blood samples, oxidative stress measurements used eight biological markers (biomarkers), and inflammatory measurements used two biological markers. The results find that each pesticide increases the risk of at least three of the six cancers. Markers for oxidative stress from pesticide exposure, including iron, aspartate aminotransferase (ASTâ€”an enzyme found in the liver, muscle, and other organs), and gamma-glutamyl transferase (GGTâ€”another enzyme found in the liver and throughout the body), have a positive association with cancer risk.
The connection between pesticides and associated cancer risks is not a new finding. Many pesticides areÂ â€śknown or probableâ€ťÂ carcinogens (cancer-causing agents), and widespread uses only amplify chemical hazards, adversely affecting human health.Â Several studiesÂ link pesticide use and residue to various cancers, from the more prevalentÂ breast cancerÂ to the rareÂ kidney cancer, nephroblastomaÂ (Wilmsâ€™ tumor).Â Sixty-six percentÂ of all cancers have links to environmental factors, especially in occupations of high chemical use. At leastÂ 45 different cancersÂ have associations with work-related chemical exposure. Although the link between agricultural practices and pesticide-related illnesses is stark, overÂ 63 percentÂ of commonly used lawn pesticides andÂ 70 percentÂ of commonly used school pesticides haveÂ linksÂ to cancer. ManyÂ cancer-causing substancesÂ are endocrine disruptors, directly affecting traditional endocrine glands and theirÂ hormones and receptorsÂ (e.g., estrogens, anti-androgens, thyroid hormones) while greatly influencing hormone cancer incidents among humans (e.g., unrein, breast, prostate, and thyroid cancers). Moreover, severalÂ studies and reports, including U.S. Environmental Protection Agency (EPA) data,Â identifyÂ hundreds of chemicals as influential factors associated with hormone-related cancer risk.Â
All chemicals in this study produce different biological markers of oxidative stress, and the concentrations of oxidative stress biological markers can indicate an increased risk of cancer. Many of the studyâ€™s patients with cancer had a history of exposure to 2,4-D, PYRs, and OPs (like parathion), with prostate cancer being the most significant. However, the oxidative stress biological marker AST demonstrated an increased cancer risk of colon, prostate, breast, and cervical cancers among patients exposed to 2,4-D and melanoma, prostate cancer, and breast cancer among patients exposed to the OP diazinon. This study considers the role oxidative stress from pesticide exposure plays a role in cancer development, highlighting how previous studies tend to focus on the endocrine-disrupting effects of pesticide exposure on cancer development. Discovering additional mechanisms involved in pesticide-mediated cancers can give researchers a holistic understanding of disease risk from chemical exposure.
There is a limited understanding of the etiology of pesticide-induced diseases, including predictable lag time between chemical exposure, health impacts, and epidemiological data. Exposure to pesticides can increase the risk of developing chronic illnesses.Â CancerÂ is one of the leading causes of death worldwide, with over eight million people succumbing to the disease every year. Notably,Â IARC predicts an increaseÂ in new cancer cases from 19.3 million to 30.2 million per year by 2040. Therefore, studies related to pesticides and cancer will aid in understanding the underlying mechanisms that cause the disease. Consequently, it is essential to understand the health implications of pesticide use and exposure for humans, particularly when pesticides increase chronic disease risk. Beyond Pesticides tracks the most recent news and studies on pesticides and related topics through theÂ Daily News BlogÂ andÂ Pesticide-Induced Diseases Database (PIDD). For more information on the adverse effects of pesticides on human health, see PIDD pages onÂ cancer,Â endocrine disruption, and other diseases.
Moreover, proper prevention practices, likeÂ buying,Â growing, and supporting organics, can eliminate exposure to toxic pesticides. Organic agriculture has manyÂ healthÂ andÂ environmental benefits, as it curtails the need for chemical-intensive agricultural practices.Â Regenerative organic agricultureÂ nurtures soil health through organic carbon sequestration, preventing pests and generating a higher return than chemical-intensive agriculture. For more information on why organic is the right choice, see the Beyond Pesticides webpage,Â Health Benefits of Organic Agriculture.Â
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Source: Environmental Sciences Europe