title: Cancer incidence among pesticide applicators exposed to butylate in the Agricultural Health Study (AHS).
abstract: Although limited, epidemiologic studies suggest possible associations between butylate use and cancer risk, specifically prostate cancer and non-Hodgkin lymphoma (NHL). We examined butylate use and cancer risk more broadly in the AHS, a cohort of licensed pesticide applicators in Iowa and North Carolina. Pesticide use information was collected using self-administered questionnaires. Poisson regression was used to calculate rate ratios (RR) and 95% confidence intervals (CI). Two exposure metrics were used: lifetime exposure days (LD) and intensity-weighted lifetime exposure days (IWLD). We used two referent groups: unexposed to butylate and the lowest butylate usage category. This analysis included 19,655 applicators with complete butylate use information; 5297 applicators were exposed to butylate, making this the largest study of butylate to date. The mean follow-up time since enrollment was 9 years. Prostate cancer risk was significantly elevated among applicators in the highest LD category in both referent groups (low-exposed referent: RR(LD)=2.09, 95% CI=1.27-3.44). We observed a significantly elevated joint effect of prostate cancer family history and high butylate usage across both exposure metrics and both referent groups (low-exposed referent: RR(LD)=2.00, 95% CI=1.07-3.74), and a non-significant, elevated interaction between butylate use and prostate cancer family history, similar to a previous AHS finding. Statistically significant increased risks and exposure-response trends were seen for all lymphohematopoietic cancers (AL) and NHL for both exposure metrics and referent groups (low-exposed referent: AL:RR(LD)=2.27, 95% CI=1.18-4.37; NHL: RR(LD)=3.44, 95% CI=1.29-9.21). Our analysis did not find meaningful associations for other cancers analyzed. Further study is warranted for AL, NHL and prostate cancers.
authors.affiliation: Epidemiology and Genetics Research Program, Division of Cancer Control and Population Sciences, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Rockville, MD 20852, USA.
authors.forename: Shannon M
authors.initials: SM
authors.lastname: Lynch
authors.forename: Rajeev
authors.initials: R
authors.lastname: Mahajan
authors.forename: Laura E
authors.initials: LE
authors.lastname: Beane Freeman
authors.forename: Jane A
authors.initials: JA
authors.lastname: Hoppin
authors.forename: Michael C R
authors.initials: MC
authors.lastname: Alavanja
mesh_terms: D000328:Adult; D000382:Agricultural Workers' Diseases / Q000139:chemically induced* / Q000453:epidemiology; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007484:Iowa / Q000453:epidemiology; D008228:Lymphoma, Non-Hodgkin / Q000139:chemically induced* / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009657:North Carolina / Q000453:epidemiology; D016273:Occupational Exposure / Q000009:adverse effects*; D010575:Pesticides / Q000506:poisoning*; D015995:Prevalence; D011446:Prospective Studies; D011471:Prostatic Neoplasms / Q000139:chemically induced* / Q000453:epidemiology; D011795:Surveys and Questionnaires; D013859:Thiocarbamates / Q000506:poisoning*
chemical_list: D010575:Pesticides; D013859:Thiocarbamates; C023898:butylate