Pesticide Exposure Linked to Increased RA Risk in Women, suggests study

A new study published in the journal of Arthritis & Rheumatology revealed that women exposed to agricultural pesticides, either through direct farm work or as farmers’ wives, face a higher risk of developing rheumatoid arthritis (RA). The analysis confirmed associations between RA and exposure to certain insecticides and fungicides, though not most herbicides. Few prior studies have explored these risks specifically in women, despite widespread chemical use in farming.

Rheumatoid arthritis is a systemic autoimmune disease that affects 2% of Americans over 60. The occupation of farming has also been linked to RA. Toxicology studies indicate that several pesticides have complicated effects on the immune system, and exposure to pesticides is an often proposed reason for this relationship.

Prior research indicated a moderate but non-statistically significant association between pesticide usage and RA. Therefore, in the Agricultural Health Study, Christine Parks and her team looked at the relationship between RA risk and pesticide usage among female wives of licensed pesticide applicators.

The participants (N=32,126) enrolled in North Carolina and Iowa between 1993 and 1997. Follow-up surveys (1999–2021) were used to identify incident RA cases, which were then verified by medical records, pertinent medication usage, or Medicare claims data (1999–2016), or Medicare claims in the absence of RA questionnaire data. Non-cases had no Medicare claims for RA and no RA reports.

This research looked in to the correlations with 32 particular pesticides (personal lifetime usage recorded at enrollment, updated in 1999-2003) and pesticide classes among those with complete covariate data (N=410 cases and 21,850 non-cases). After controlling for age, state, education, smoking pack-years, body mass index, and correlated pesticides (rho>0.35), they computed odds ratios (OR) and 95% CI.

Organochlorine [DDT (1.89;1.30-2.75), organophosphate insecticides [coumaphos (2.32;1.29-4.19), lindane (1.97;1.12-3.47)], malathion (1.21;0.91-1.62)], the carbamate insecticide carbofuran (1.87;0.97-3.63), and the use of permethrin or pyrethroid insecticides on crops (1.56;0.92-2.64) or livestock (1.69;1.07-2.68) were correlated with incident RA. Herbicide use did not correlate with RA, with the exception of metribuzin (1.88;0.94-3.79). RA was also linked to the fungicides metalaxyl (2.49;1.41-4.40) and captan (1.78;1.13-2.83).

Overall, these results suggest that certain pesticides and persistent organochlorine insecticides used in residential or public health settings may raise the incidence of RA in women. The study found links between RA and exposure to certain fungicides and insecticides, but not the majority of herbicides.

Source:

Parks, C. G., Leyzarovich, D., Hamra, G. B., Costenbader, K. H., Chen, D., Hofmann, J. N., Beane Freeman, L. E., & Sandler, D. P. (2025). Associations of specific pesticides and incident rheumatoid arthritis among female spouses in the Agricultural Health Study. Arthritis & Rheumatology. https://doi.org/10.1002/art.43318