Cancer incidence among pesticide applicators exposed to atrazine in the Agricultural Health Study.
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).
Rusiecki
Jennifer A
JA
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 20892-7240, USA.
De Roos
Anneclaire
A
Lee
Won Jin
WJ
Dosemeci
Mustafa
M
Lubin
Jay H
JH
Hoppin
Jane A
JA
Blair
Aaron
A
Alavanja
Michael C R
MC
D000328:Adult; D000368:Aged; D000382:Agricultural Workers' Diseases / Q000139:chemically induced* / Q000453:epidemiology*; D001280:Atrazine / Q000009:adverse effects*; D002273:Carcinogens / Q000009:adverse effects*; 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; D012107:Research Design; D011795:Surveys and Questionnaires
D002273:Carcinogens; D006540:Herbicides; D001280:Atrazine