title: S-ethyl-N,N-dipropylthiocarbamate exposure and cancer incidence among male pesticide applicators in the agricultural health study: a prospective cohort.
abstract: BACKGROUND
  The Agricultural Health Study (AHS) is a prospective cohort study of licensed pesticide applicators from Iowa and North Carolina enrolled between 1993 and 1997. EPTC (S-ethyl-N,N-dipropylthiocarbamate) is a thiocarbamate herbicide used in every region of the United States. The U.S. Environmental Protection Agency reports that EPTC is most likely not a human carcinogen; however, the previous epidemiologic data on EPTC exposure and cancer risk were limited.
  
  
  OBJECTIVE
  The purpose of this study was to examine cancer incidence and EPTC use in 48,378 male pesticide applicators enrolled in the AHS.
  
  
  METHODS
  We estimated the rate ratio (RR) and 95% confidence intervals (CIs) for all cancers and selected cancer sites using Poisson regression. We assessed EPTC exposure using two quantitative metrics: lifetime exposure days and intensity-weighted lifetime exposure days, a measure that accounts for application factors that modify personal exposure likelihood.
  
  
  RESULTS
  Among the 9,878 applicators exposed to EPTC, 470 incident cancer cases were diagnosed during the follow-up period ending December 2004 compared with the 1,824 cases among individuals reporting no use. Although EPTC was associated with colon cancer in the highest tertile of both lifetime exposure days and intensity-weighted lifetime days (RR = 2.09; 95% CI, 1.26-3.47 and RR = 2.05; 95% CI, 1.34-3.14, respectively) and the trend test was < 0.01 for both, the pattern of RR was not monotonic with increasing use. There was a suggestion of an association with leukemia. No other associations were observed.
  
  
  CONCLUSIONS
  In this analysis, EPTC use appeared to be associated with colon cancer and leukemia. However, given the relatively small number of cases in the highest exposure tertile, results should be interpreted with caution, and further investigations are needed.
authors.affiliation: Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Rockville, Maryland, USA.
authors.forename: Dana M
authors.initials: DM
authors.lastname: van Bemmel
authors.forename: Kala
authors.initials: K
authors.lastname: Visvanathan
authors.forename: Laura E
authors.initials: LE
authors.lastname: Beane Freeman
authors.forename: Joseph
authors.initials: J
authors.lastname: Coble
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; D015331:Cohort Studies; D006540:Herbicides / Q000633:toxicity*; D006801:Humans; D015994:Incidence; D007484:Iowa / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000139:chemically induced* / Q000453:epidemiology; D009657:North Carolina / Q000453:epidemiology; D013859:Thiocarbamates / Q000633:toxicity*
chemical_list: D006540:Herbicides; D013859:Thiocarbamates; C036251:EPTC