title: Atrazine and cancer incidence among pesticide applicators in the agricultural health study (1994-2007).
abstract: BACKGROUND
  Atrazine is a triazine herbicide used widely in the United States. Although it is an animal carcinogen, the mechanism in rodents does not appear to operate in humans. Few epidemiologic studies have provided evidence for an association.
  
  
  METHODS
  The Agricultural Health Study (AHS) is a prospective cohort that includes 57,310 licensed pesticide applicators. In this report, we extend a previous AHS analysis of cancer risk associated with self-reported atrazine use with six additional years of follow-up and more than twice as many cancer cases. Using Poisson regression, we calculated relative risk estimates and 95% confidence intervals for lifetime use of atrazine and intensity-weighted lifetime days, which accounts for factors that impact exposure.
  
  
  RESULTS
  Overall, 36,357 (68%) of applicators reported using atrazine, among whom there were 3,146 cancer cases. There was no increase among atrazine users in overall cancer risk or at most cancer sites in the higher exposure categories compared with the lowest. Based on 29 exposed cases of thyroid cancer, there was a statistically significant risk in the second and fourth quartiles of intensity-weighted lifetime days. There was a similar pattern for lifetime days, but neither the risk estimates nor the trend were statistically significant and for neither metric was the trend monotonic.
  
  
  CONCLUSIONS
  Overall, there was no consistent evidence of an association between atrazine use and any cancer site. There was a suggestion of increased risk of thyroid cancer, but these results are based on relatively small numbers and minimal supporting evidence.
authors.affiliation: Division of Cancer, Epidemiology, and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland, USA. freemala@mail.nih.gov
authors.forename: Laura E Beane
authors.initials: LE
authors.lastname: Freeman
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Rusiecki
authors.forename: Jane A
authors.initials: JA
authors.lastname: Hoppin
authors.forename: Jay H
authors.initials: JH
authors.lastname: Lubin
authors.forename: Stella
authors.initials: S
authors.lastname: Koutros
authors.forename: Gabriella
authors.initials: G
authors.lastname: Andreotti
authors.forename: Shelia Hoar
authors.initials: SH
authors.lastname: Zahm
authors.forename: Cynthia J
authors.initials: CJ
authors.lastname: Hines
authors.forename: Joseph B
authors.initials: JB
authors.lastname: Coble
authors.forename: Francesco
authors.initials: F
authors.lastname: Barone-Adesi
authors.forename: Jennifer
authors.initials: J
authors.lastname: Sloan
authors.forename: Dale P
authors.initials: DP
authors.lastname: Sandler
authors.forename: Aaron
authors.initials: A
authors.lastname: Blair
authors.forename: Michael C R
authors.initials: MC
authors.lastname: Alavanja
mesh_terms: D000328:Adult; D000368:Aged; D000382:Agricultural Workers' Diseases / Q000139:chemically induced* / Q000453:epidemiology*; D001280:Atrazine / Q000633:toxicity*; D002273:Carcinogens / Q000633:toxicity*; D015331:Cohort Studies; D016001:Confidence Intervals; D005260:Female; D006540:Herbicides / Q000009:adverse effects; D006801:Humans; D007484:Iowa / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000139:chemically induced* / Q000453:epidemiology*; D009657:North Carolina / Q000453:epidemiology; D016017:Odds Ratio; D016012:Poisson Distribution; D011446:Prospective Studies; D011795:Surveys and Questionnaires; D013964:Thyroid Neoplasms / Q000139:chemically induced / Q000453:epidemiology
chemical_list: D002273:Carcinogens; D006540:Herbicides; D001280:Atrazine