Cancer Incidence Among Pesticide Applicators Exposed to Atrazine in the Agricultural Health Study

Authors

Jennifer A. Rusiecki, Department of Health and Human Services, Rockville, MD
Anneclaire De Roos, University of Washington, Seattle
Won Jin Lee, Department of Health and Human Services, Rockville, MD
Mustafa Dosemeci, Department of Health and Human Services, Rockville, MD
Jay H. Lubin, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC
Jane A. Hoppin, Department of Health and Human Services, Rockville, MD
Aaron Blair, Department of Health and Human Services, Rockville, MD
Michael C. R. Alavanja, Department of Health and Human Services, Rockville, MD

Date of this Version

9-15-2004

Comments

Published in Journal of the National Cancer Institute, Vol. 96, No. 18, September 15, 2004.

Abstract

Background: Atrazine is the most heavily applied agricultural pesticide for crop production in the United States. Both animal and human studies have suggested that atrazine is possibly carcinogenic, but results have been mixed. We evaluated cancer incidence in atrazine-exposed pesticide applicators among 53 943 participants in the Agricultural Health Study, a prospective cohort study of licensed pesticide applicators in Iowa and North Carolina.
Methods: We obtained detailed pesticide exposure information using a self-administered questionnaire completed at the time of enrollment (1993–1997). Cancer incidence was followed through December 31, 2001. We used adjusted Poisson regression to calculate rate ratios (RRs) and 95% confidence intervals (CIs) of multiple types of cancer among atrazine exposed applicators. P_trend values were calculated using atrazine exposure as a continuous variable, and all statistical tests were two-sided. Two exposure metrics were used: quartiles of lifetime days of exposure and quartiles of intensity-weighted lifetime days of exposure.
Results: 36 513 (68%) applicators reported ever using atrazine; exposure was not associated with overall cancer incidence. Comparisons of cancer incidence in applicators with the highest atrazine exposure and those with the lowest exposure, assessed by lifetime days (RR_LD) and intensity-weighted lifetime days (RR_IWLD) of exposure yielded the following results: prostate cancer, RR_LD = 0.88, 95% CI = 0.63 to 1.23, P_trend = .26, and RR_IWLD = 0.89, 95% CI = 0.63 to 1.25, P_trend = .35; lung cancer, RR_LD = 1.91, 95% CI = 0.93 to 3.94, P_trend = .08, and RR_IWLD = 1.37, 95% CI = 0.65 to 2.86, P_trend = .19; bladder cancer, RR_LD = 3.06, 95% CI = 0.86 to 10.81, P_trend =.18, and RR_IWLD = 0.85, 95% CI = 0.24 to 2.94, P_trend = .71; non-Hodgkin lymphoma, RR_LD = 1.61, 95% CI = 0.62 to 4.16, P_trend = .35, and RR_IWLD = 1.75, 95% CI = 0.73 to 4.20, P_trend = .14; and multiple myeloma, RR_LD = 1.60, 95% CI = 0.37 to 7.01, P_trend = .41, and RR_IWLD = 2.17, 95% CI = 0.45 to 10.32, P_trend = .21.
Conclusions: Our analyses did not find any clear associations between atrazine exposure and any cancer analyzed. However, further studies are warranted for tumor types in which there was a suggestion of trend (lung, bladder, non-Hodgkin lymphoma, and multiple myeloma).