Title: Common farming pesticides linked to rheumatoid arthritis
A study published in the journal Scientific Reports provides a list of pesticides that can increase the risk of rheumatoid arthritis among users of pesticides.
The use of malathion and carbaryl has been linked to increased rheumatoid arthritis risk. These pesticides are among the most commonly used in agricultural, public health, and residential settings in Australia, highlighting exposures risks that go beyond farming populations.
Rheumatoid arthritis is a systemic autoimmune disease associated with long-term damage and disabilities. The disease is characterised by joint inflammation and multiorgan adversities.
The study included 22,642 licensed pesticide applicators enrolled between 1993 and 1997 from North Carolina and Iowa. The risk of rheumatoid arthritis was examined in relation to the lifetime use of 45 pesticides.
Nine pesticides were identified that increased the risk of rheumatoid arthritis. These include four insecticides (malathion, phorate, carbaryl, and carbofuran), four herbicides (alachlor, metolachlor, S-Ethyl dipropyl thiocarbamate, and metribuzin), and one fungicide (benomyl). Exposure-response relationships, which suggest dose-dependent risks, were observed for malathion and carbofuran.
The study separately analyzed the risk of rheumatoid arthritis in relation to atrazine, alachlor, and metolachlor exposure, as these pesticides are frequently used together as products or tank mixtures. The findings revealed that compared to non-users, the risk of rheumatoid arthritis was elevated only among participants who used atrazine together with alachlor and/or metolachlor.
The study suggests pesticides may contribute to rheumatoid arthritis through mechanisms such as immune dysregulation, endocrine disruption, and epigenetic changes, which could have broader implications for autoimmune and inflammatory diseases.
Journal reference: Parks, C. G., Leyzarovich, D., Hamra, G. B., Costenbader, K. H., Chen, D., Hofmann, J. N., Freeman, L. E., & Sandler, D. P. (2024). Associations between pesticide use and rheumatoid arthritis among older farmers in the Agricultural Health Study. Scientific Reports, 14(1), 1-14. https://www.nature.com/articles/s41598-024-76179-2
