Cancer incidence among pesticide applicators exposed to captan in the Agricultural Health Study

Objective Captan is a widely used antifungal pesticide whose potential to cause cancer in humans is uncertain. Methods We evaluated the incidence of cancer among pesticide applicators exposed to captan in the Agricultural Health Study. Detailed information on pesticide exposure and lifestyle factors was obtained from self-administered enrollment questionnaires completed between 1993 and 1997. Results Of the 48,986 applicators enrolled 4,383 (9%) had applied captan. Median follow-up time was 9.14 years. Poisson regression analysis was used to estimate relative risks (RR) for cancer subtypes by tertiles of captan exposure. We investigated risk for all cancers combined and sites of cancer for which at least 15 cases occurred among captan-exposed applicators. These sites included cancers of the prostate, lung, and colon, blood-related cancers, and colorectal cancers. During follow-up 2,912 incident primary cases of cancer were identified. No association between the highest tertile of captan exposure (>67.375 intensity-weighted days) and development of all cancers (RR = 0.89; 95% CI, 0.71-1.13) or cancer of any specific site was observed. Conclusion Although our study is limited by low numbers of observed cancer cases and follow-up time of 9.14 years, it does not provide evidence of an increased risk for the development of cancer at the investigated sites.