Pesticide use and incident hyperthyroidism in farmers in the Agricultural Health Study

Srishti Shrestha, Christine G. Parks, Whitney S. Goldner, Freya Kamel, David M. Umbach, Mary H. Ward, Catherine C. Lerro, Stella Koutros, Jonathan N. Hofmann, Laura E. Beane Freeman, Dale P. Sandler

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Background Few studies have evaluated associations between pesticides and hyperthyroidism. Objective We evaluated associations between specific pesticides and incident hyperthyroidism in private pesticide applicators in the Agricultural Health Study. Methods We used Cox proportional hazards models to estimate HRs and 95% CIs for associations between pesticide use at enrolment and hyperthyroidism (n=271) in 35 150 applicators (mostly men), adjusting for potential confounders. Results Ever use of several pesticides (organophosphate insecticide malathion, fungicide maneb/mancozeb, herbicides dicamba, metolachlor, and atrazine in overall sample and chlorimuron ethyl among those ≤62 years) was associated with reduced hyperthyroidism risk, with HRs ranging from 0.50 (95% CI 0.30 to 0.83) for maneb/mancozeb to 0.77 (95% CI 0.59 to 1.00) for atrazine. Hyperthyroidism risk was lowest among those with higher intensity-weighted lifetime days of using carbofuran and chlorpyrifos (p trend ≤0.05). Conclusions Observed associations between pesticides and decreased risk of hyperthyroidism warrant further investigation.

Original languageEnglish (US)
Pages (from-to)332-335
Number of pages4
JournalOccupational and Environmental Medicine
Issue number5
StatePublished - May 1 2019


  • Agricultural Health Study
  • hyperthyroidism
  • pesticides

ASJC Scopus subject areas

  • Public Health, Environmental and Occupational Health


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