Dichlorvos exposure and human cancer risk: results from the Agricultural Health Study

Objectives We evaluated cancer risk from DDVP (2,2-Dichloroethenyl dimethylphosphate) exposure among pesticide applicators enrolled in the Agricultural Health Study (AHS) cohort. Methods The AHS is a cohort of 57,311 pesticide applicators in North Carolina and Iowa, enrolled from 1993 to 1997 and followed for cancer through 2004. A comprehensive questionnaire collected information on exposure to DDVP and potential confounders. Among the 49,762 licensed pesticide applicators eligible for analysis, 4,613 reported use of DDVP. DDVP exposure was classified as intensity-weighted cumulative exposure days (IWED), calculated as [years of use x days per year x intensity level]. Poisson regression analysis was used to calculate rate ratios (RR) and 95% confidence intervals (CI) to evaluate the association of DDVP exposure among 2,943 incident cases of cancer. Results DDVP exposure was not associated with any cancer studied here. We observed no elevation in risk among lymphohematopoietic cancers, RR = 1.00 (95% CI 0.51, 1.96) and a small excess risk associated with exposure among those with a family history of prostate cancer (RR = 1.18 (95% CI 0.73, 1.82). Conclusion We find little evidence of an association between cumulative lifetime use of DDVP and risk of any cancer at this stage of follow up of the AHS.