Objectives
Organophosphates (OP) are among the most commonly used insecticides. OPs have been linked to cancer risk in some epidemiologic studies, which have been largely conducted in predominantly male populations. We evaluated personal use of specific OPs and cancer incidence among female spouses of pesticide applicators in the prospective Agricultural Health Study cohort.
Methods
At enrollment (1993–1997) spouses provided information about ever use of specific pesticides, including ten OPs, demographic information, reproductive health history, and other potential confounders. We used Poisson regression to estimate relative risks (RRs) and 95% confidence intervals (95% CIs) for all cancers diagnosed through 2010 for North Carolina and 2011 for Iowa.
Results
Among 30,003 women, 25.9% reported OP use, and 718 OP-exposed women were diagnosed with cancer during the follow-up period. Any OP use was associated with an elevated risk of breast cancer (RR = 1.20, 95% CI: 1.01, 1.43). Malathion, the most commonly reported OP, was associated with increased risk of thyroid cancer (RR = 2.04, 95% CI: 1.14, 3.63) and decreased risk of non-Hodgkin lymphoma (RR = 0.64, 95% CI: 0.41, 0.99). Diazinon use was associated with ovarian cancer (RR = 1.87, 95% CI: 1.02, 3.43).
Conclusions
We observed increased risk with OP use for several hormonally-related cancers, including breast, thyroid, and ovary, suggesting potential for hormonally-mediated effects. This study represents the first comprehensive analysis of OP use and cancer risk among women, and thus a need for further evaluation.