Pesticide Exposure Could Lead to Higher Rheumatoid Arthritis Risks for Women Farm Workers: Study

Highest risk was linked to certain insecticides, including already restricted products like chlorpyrifos and parathion.

A new study warns that women face a higher risk of rheumatoid arthritis if they are exposed to pesticides, either from being a farmworker or being married to one.

The findings were published in the journal Arthritis & Rheumatology on July 16, involving data gathered by government investigators, who report that exposure to certain pesticides could increase the risk of rheumatoid arthritis in women by nearly 150%.

Rheumatoid arthritis is a chronic autoimmune disease that affects the joints, especially the fingers, wrists and knees. It causes symptoms like swelling, pain and stiffness. Over time, the inflammation can cause joint damage.

Prior research has drawn links between exposure to certain pesticides and herbicides to increased risks of health issues, including rheumatoid arthritis and other serious conditions, like Parkinson’s disease and non-Hodgkin’s lymphoma.

For this new study, researchers from the National Institutes of Health (NIH) examined data on more than 32,000 participants in the Agricultural Health Study from 1993 to 1997, who were from North Carolina and Iowa.

Participants were female spouses of licensed pesticide applicators or farmworkers themselves. Rheumatoid arthritis cases were identified in follow-up questionnaires from 1999 to 2021, and confirmed by medical records, relevant medication use or Medicare claims data.

The research team, led by Dr. Christine G. Parks, examined the data, looking for associations between rheumatoid arthritis and 32 specific pesticides. They determined that, overall, women who were exposed to pesticides had a higher risk of developing rheumatoid arthritis.

However, the researchers found that increased risk varied depending on the type of pesticide, with the risk of developing rheumatoid arthritis being 89% higher for those who used organochlorine pesticides, also known as DDT. The increased risk of rheumatoid arthritis was 97% higher for lindane, 21% higher for malathion, 87% higher for carbamate insecticide carbofuran, and 56% higher for permethrin.

The highest risk was found among those using organophosphate insecticides, like chlorpyrifos and parathion, which increased a woman’s chance of a rheumatoid arthritis diagnosis by 132%.

Researchers also tested the association between rheumatoid arthritis and the use of herbicides. While overall there was no link between herbicides and rheumatoid arthritis, some specific formulations were exceptions, with a 149% increased risk for metalaxyl, 88% higher for metribuzin use, and 78% higher for fungicide captan use.

Pesticide Exposure Health Side Effects

This is not the first time pesticides and herbicides have been linked to an increased risk of rheumatoid arthritis. Another National Institutes of Health study published last year reached similar conclusions, specifically linking four herbicides, four insecticides and a fungicide to the increased risk.

Exposure to pesticides has been more frequently linked to Parkinson’s disease, with a study earlier this year finding an association between living near golf courses and an increased risk of the neurological disorder. The study indicated nearby residents had a 126% increased risk of Parkinson’s disease due to pesticide exposure.

Researchers warn many of the same pesticides are found in 75% of all non-organic produce in the United States, determining that strawberries and leafy greens are often the most contaminated.

Pesticide Exposure Lawsuits

A number of pesticide and herbicide manufacturers have faced mass tort litigation in recent years, with lawsuits filed by individuals exposed to the chemicals who later linked them to diagnoses of cancer and other ailments, sometimes leading to massive settlement agreements to resolve claims.

Bayer and Monsanto still face thousands of Roundup lawsuits, even after paying $10 billion in settlements over the course of several years. The claims allege Roundup is linked to an increased risk of developing non-Hodgkins Lymphoma and other similar cancers.

Similarly, about 6,000 Paraquat lawsuits are being pursued against Chevron Chemical Company and Syngenta, claiming the makers of the popular grass and weed killer failed to warn users about the risk of developing Parkinson’s disease.

As lawyers were finalizing preparations for a series of early Paraquat lawsuit bellwether trials expected to go before juries later this year, the Court was notified that a tentative Paraquat settlement agreement had been reached to resolve most of the claims in April 2025. However, the terms have yet to be finalized.

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