Chlorothalonil exposure and cancer incidence among pesticide applicator participants in the agricultural health study.
BACKGROUND
Chlorothalonil is a broad spectrum, non-systemic fungicide widely used to control diseases affecting over 50 fruit, vegetable, and agricultural crops. Despite its extensive use for over 30 years, little is known about the potential human carcinogenicity associated with the routine application of chlorothalonil. Rodent studies have shown evidence of renal tubular carcinomas and adenomas. We explored cancer incidence with chlorothalonil exposure using data from the Agricultural Health Study, a prospective cohort of licensed pesticide applicators in Iowa and North Carolina.


METHODS
Licensed private and commercial pesticide applicators were recruited into this study from 1993 to 1997. Detailed information regarding pesticide use was obtained via self-administered questionnaires. Cancer incidence was followed through December 31, 2004. Chlorothalonil exposure was classified by lifetime exposure days and intensity-weighted lifetime exposure days, and then categorized into tertiles. The intensity-weighted lifetime exposure days metric was calculated based on a complex algorithm which includes pesticide application methods among other factors. This may increase or decrease exposure.


RESULTS
Of the 47,625 pesticide applicators included in this analysis, 3657 applicators reported using chlorothalonil with a median of 3.5 application days per year. Chlorothalonil was not associated with overall cancer incidence, nor did we find any association with colon, lung, and prostate cancers--the only cancers for which we had sufficient numbers to explore associations.


CONCLUSIONS
We did not find any strong evidence for an association between chlorothalonil and the cancers investigated. Although animal studies have suggested renal cancer may be associated with chlorothalonil, we had insufficient data to evaluate this cancer.
Mozzachio
Alicia M
AM
Department of Preventive Medicine and Biometrics, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4799, USA.
Rusiecki
Jennifer A
JA
Hoppin
Jane A
JA
Mahajan
Rajeev
R
Patel
Rahulkumar
R
Beane-Freeman
Laura
L
Alavanja
Michael C R
MC
D000383:Agriculture / Q000706:statistics & numerical data*; D015331:Cohort Studies; D005659:Fungicides, Industrial / Q000633:toxicity*; D006801:Humans; D009369:Neoplasms / Q000139:chemically induced* / Q000453:epidemiology*; D009570:Nitriles / Q000633:toxicity*; D009657:North Carolina / Q000453:epidemiology; D016273:Occupational Exposure / Q000032:analysis*; D011446:Prospective Studies
D005659:Fungicides, Industrial; D009570:Nitriles; C005806:tetrachloroisophthalonitrile
Epidemiology. 2002 Jan;13(1):94-9
11805592
Ann Occup Hyg. 2002 Mar;46(2):245-60
12074034
J Expo Anal Environ Epidemiol. 2002 Sep;12(5):313-8
12198579
Ann N Y Acad Sci. 2006 Sep;1076:366-77
17119216
Environ Health Perspect. 1996 Apr;104(4):362-9
8732939
Regul Toxicol Pharmacol. 1996 Aug;24(1 Pt 1):69-84
8921547
Cancer Invest. 2005;23(8):700-11
16377589
Scand J Work Environ Health. 1992 Aug;18(4):209-15
1411362