title: Heterocyclic aromatic amine pesticide use and human cancer risk: results from the U.S. Agricultural Health Study.
abstract: Imazethapyr, a heterocyclic aromatic amine, is a widely used crop herbicide first registered for use in the United States in 1989. We evaluated cancer incidence among imazethapyr-exposed pesticide applicators enrolled in the Agricultural Health Study (AHS). The AHS is a prospective cohort of 57,311 licensed pesticide applicators in the U.S., enrolled from 1993-1997. Among the 49,398 licensed pesticide applicators eligible for analysis, 20,646 applicators reported use of imazethapyr and 2,907 incident cancers developed through 2004. Imazethapyr exposure was classified by intensity-weighted lifetime exposure days calculated as [years of use x days per year x intensity level]. Poisson regression analysis was used to evaluate the relationship between imazethapyr exposure and cancer incidence. We found significant trends in risk with increasing lifetime exposure for bladder cancer (p for trend 0.01) and colon cancer (p for trend 0.02). Rate ratios (RRs) were increased by 137% for bladder cancer and 78% for colon cancer when the highest exposed were compared to the nonexposed. The excess risk for colon cancer was limited to proximal cancers, (RR = 2.73, 95% confidence intervals 1.42, 5.25, p for trend 0.001). No association was observed for prostate, lung, rectum, kidney, oral, pancreas, lymphohematopoietic cancers or melanoma. These findings provide new evidence that exposure to aromatic amine pesticides may be an overlooked exposure in the etiology of bladder and colon cancer. The use of imazethapyr and other imidazolinone compounds should continue to be evaluated for potential risk to humans.
authors.affiliation: Occupational and Environmental Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Rockville, MD 20852, USA. KoutrosS@mail.nih.gov
authors.forename: Stella
authors.initials: S
authors.lastname: Koutros
authors.forename: Charles F
authors.initials: CF
authors.lastname: Lynch
authors.forename: Xiaomei
authors.initials: X
authors.lastname: Ma
authors.forename: Won Jin
authors.initials: WJ
authors.lastname: Lee
authors.forename: Jane A
authors.initials: JA
authors.lastname: Hoppin
authors.forename: Carol H
authors.initials: CH
authors.lastname: Christensen
authors.forename: Gabriella
authors.initials: G
authors.lastname: Andreotti
authors.forename: Laura Beane
authors.initials: LB
authors.lastname: Freeman
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Rusiecki
authors.forename: Lifang
authors.initials: L
authors.lastname: Hou
authors.forename: Dale P
authors.initials: DP
authors.lastname: Sandler
authors.forename: Michael C R
authors.initials: MC
authors.lastname: Alavanja
mesh_terms: D000328:Adult; D000368:Aged; D000382:Agricultural Workers' Diseases / Q000139:chemically induced*; D003110:Colonic Neoplasms / Q000139:chemically induced*; D005260:Female; D006540:Herbicides / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009539:Nicotinic Acids / Q000009:adverse effects*; D016273:Occupational Exposure / Q000009:adverse effects*; D012307:Risk Factors; D001749:Urinary Bladder Neoplasms / Q000139:chemically induced*
chemical_list: D006540:Herbicides; D009539:Nicotinic Acids; C093630:imazethapyr