Farmers Exposed to Certain Pesticides Face an Increased Risk of Rheumatoid Arthritis

New research suggests that there may be an increased risk of rheumatoid arthritis associated with exposure to nine different pesticides, including four insecticides, four herbicides and one fungicide.

Rheumatoid arthritis is a chronic autoimmune condition, in which an individual’s joints and surrounding tissues become inflamed, causing pain, swelling, fatigue and occasionally fever. Smoking, obesity and air pollution are known risk factors, but the exact causes are often unknown for the progressive disease, which can result in painful deformity and a lack of mobility, especially in the fingers, wrists, feet and ankles.

In findings published in the medical journal Scientific Reports on December 2, researchers from the U.S. National Institutes of Health (NIH) indicate that an individual’s risk of developing rheumatoid arthritis also increases from exposure to certain pesticides, some of which are still commonly used in the U.S.

Researchers from NIH’s National Institute of Environmental Health Sciences examined data gathered through the Agricultural Health Study conducted from 1993 through 1995, to review the effects of 45 different pesticides used by approximately 89,000 farmers and their spouses in North Carolina and Iowa.

The team of researchers, which were led by Christine G. Parks, found that four insecticides, four herbicides and a fungicide were linked to increased rates of rheumatoid arthritis in the farmers studied. In particular, the researchers found an increased rheumatoid arthritis risk associated with the following pesticides:

Although carbofuran and benomyl are no longer available in the U.S., the seven remaining pesticides are still commonly used by farmers throughout the United States, including popular brand names such as Lasso (alachlor), Sevin (carbaryl), Ovide (malathion), Dual Magnum (metolachlor), Sencor (metribuzin) and Thimet (phorate).

Parks’ team accounted for some additional rheumatoid arthritis risk factors, but not all.

“Compared to baseline models adjusting for age, state, and correlated pesticides, we saw limited evidence of additional confounding by education and smoking,” Parks said. “However, residual confounding may occur due to time-varying or passive smoking exposures, for example in childhood.”

Rheumatoid arthritis risks have also been linked to infections, diet, alcohol use and body mass index. None of which were included in the evaluations for Parks’ study.

Additional Pesticide Risks

Rheumatoid arthritis is not the only risk discovered to be related to pesticide use in recent years. Other more serious conditions have been linked to the use of popular pesticides such as Paraquat and Roundup.

Paraquat is a highly toxic herbicide developed in the early 1960s for controlling weeds and grass. However, it has also been linked to Parkinson’s disease, which has led to thousands of Paraquat Parkinson’s disease lawsuits filed throughout the federal court system.

There have also been thousands of Roundup lawsuits filed against that product’s manufacturers, Bayer and Monsanto, most of which claim that users were diagnosed with non-Hodgkin’s lymphoma and other forms of cancer after using the weedkiller.