Pancreatic cancer mortality and organochlorine pesticide exposure in California, 1989-1996

BACKGROUND: Occupational studies have suggested a possible link between organochlorine pesticides and the occurrence of pancreatic cancers. California maintains a death file and a pesticide reporting system that allows examination of this relationship for residents of high use areas. METHODS: We employed a mortality odds ratio design to compare deaths from pancreatic cancer (1989-1996) with a random sample of non-cancer deaths. Using pesticide data for three agricultural counties, we classified 102 ZIP codes in quartiles of pesticide usage for 1972-1989. Using logistic regression we estimated the effect of pesticide applications by ZIP code controlling for possible confounders. RESULTS: Among long-term residents, pancreatic cancer mortality was elevated for those living in ZIP codes with the highest use of four pesticides: 1,3-dichloropropene (1,3-d), captafol, pentachloronitrobenzene (PCNB), and dieldrin. No dose-response relationship was observed. CONCLUSIONS: Our study suggests increased pancreatic cancer mortality among long-term residents in areas of high application rates of 1,3-d (an EPA-classified probable human carcinogen), captafol, pentacholoronitrobenzene (PCNB), and dieldrin.