Article

Cancer Incidence among Pesticide Applicators Exposed to Dicamba in the Agricultural Health Study

Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland 20852, USA.
Environmental Health Perspectives (Impact Factor: 7.98). 11/2006; 114(10):1521-6. DOI: 10.1289/ehp.9204
Source: PubMed

ABSTRACT Dicamba is an herbicide commonly applied to crops in the United States and abroad. We evaluated cancer incidence among pesticide applicators exposed to dicamba in the Agricultural Health Study, a prospective cohort of licensed pesticide applicators in North Carolina and Iowa.
Detailed pesticide exposure information was obtained through a self-administered questionnaire completed from 1993 to 1997. Cancer incidence was followed through 31 December 2002 by linkage to state cancer registries. We used Poisson regression to estimate rate ratios and 95% confidence intervals for cancer subtypes by tertiles of dicamba exposure. Two dicamba exposure metrics were used: lifetime exposure days and intensity-weighted lifetime exposure days (lifetime days x intensity score).
A total of 41,969 applicators were included in the analysis, and 22,036 (52.5%) reported ever using dicamba. Exposure was not associated with overall cancer incidence nor were there strong associations with any specific type of cancer. When the reference group comprised low-exposed applicators, we observed a positive trend in risk between lifetime exposure days and lung cancer (p = 0.02), but none of the individual point estimates was significantly elevated. We also observed significant trends of increasing risk for colon cancer for both lifetime exposure days and intensity-weighted lifetime days, although these results are largely due to elevated risk at the highest exposure level. There was no apparent risk for non-Hodgkin lymphoma.
Although associations between exposure and lung and colon cancer were observed, we did not find clear evidence for an association between dicamba exposure and cancer risk.

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    • "Findings for pesticides and other agricultural exposures and cancer include several aspects of prostate cancer (family history, aggressive prostate cancer, genetic polymorphisms) [Alavanja et al., 2003; Koutros et al., 2011, 2013], contact with farm animals [Beane et al., 2012], monoclonal gammopathy of undetermined significance [Landgren et al., 2009], telomere length [Hou et al., 2013], and childhood cancer among children of pesticide applicators [Flower et al., 2004]. Many individual pesticides have been evaluated for cancer risk in human studies, some for the first time in the AHS, including atrazine [Beane et al., 2011], glyphosate [De Roos et al., 2005], diazinon [Beane et al., 2005], pendimethalin [Hou et al., 2006], metolachlor [Rusiecki et al., 2006], dicamba [Samanic et al., 2006], fonofos [Mahajan et al., 2006], organochlorine pesticides [Purdue et al., 2007], malathion [Bonner et al., 2007], dichlorvos [Koutros et al., 2008], permethrin [Rusiecki et al., 2009], metribuzin [Delancey et al., 2009], coumaphos [Christensen et al., 2010], and terbufos [Bonner et al., 2010]. "
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    ABSTRACT: Prospective cohorts have played a major role in understanding the contribution of diet, physical activity, medical conditions, and genes to the development of many diseases, but have not been widely used for occupational exposures. Studies in agriculture are an exception. We draw upon our experience using this design to study agricultural workers to identify conditions that might foster use of prospective cohorts to study other occupational settings. Prospective cohort studies are perceived by many as the strongest epidemiologic design. It allows updating of information on exposure and other factors, collection of biologic samples before disease diagnosis for biomarker studies, assessment of effect modification by genes, lifestyle, and other occupational exposures, and evaluation of a wide range of health outcomes. Increased use of prospective cohorts would be beneficial in identifying hazardous exposures in the workplace. Occupational epidemiologists should seek opportunities to initiate prospective cohorts to investigate high priority, occupational exposures. Am. J. Ind. Med. 58:113–122, 2015.
    American Journal of Industrial Medicine 02/2015; 58(2):113-122. DOI:10.1002/ajim.22403 · 1.59 Impact Factor
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    • "Exposure to Phenoxy herbicides or contaminants of phenoxy herbicides furans, dioxin, pendimethlin and metolachlor excess lung cancer death were observed in a cohort of employees from four manufacturing plants in Germany (Becher et al., 1996; Hou et al., 2006; Rusiecki et al., 2006). An association was also observed for dicamba, dieldrin and carbofuran exposure and occurrence of lung cancer (Samanic et al., 2006; Purdue et al., 2007; Bonner et al., 2005). "
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    • "Pesticide Type Cancer type(s) with exposure–response in the AHS cohort Organization U.S. EPA PMRA IARC Alachlor (Lee et al. 2004b) Herbicide All LH Likely (high doses) / not likely (low doses) Not registered in Canada Not evaluated Aldicarb (Lee et al. 2007a) Insecticide Colon Group E a Not registered in Canada Group 3 b Carbaryl (Mahajan et al. 2007) Insecticide Melanoma Likely Under re-evaluation (positive) c Group 3 b Chlorpyrifos (Lee et al. 2004a, 2007b) Insecticide Lung, rectum Group E a Negative d Not evaluated Diazinon (Alavanja et al. 2004; Beane Freeman et al. 2005) Insecticide All cancers, all LH, leukemia, lung Not likely Negative d Not evaluated Dicamba (Alavanja et al. 2004; Samanic et al. 2006) Herbicide Colon, lung Not likely Negative d Not evaluated EPTC (Andreotti et al. 2009; van Bemmel et al. 2008) Herbicide All cancers, colon, leukemia, pancreas Not likely Negative d Not evaluated Imazethapyr (Koutros et al. 2009) Herbicide Bladder, colon Not likely Under re-evaluation (negative) d Not evaluated Metolachlor (Alavanja et al. 2004) Herbicide Lung Group C e Not registered in Canada Not evaluated Pendimethalin (Alavanja et al. 2004; Andreotti et al. 2009; Hou et al. 2006) Herbicide Lung, rectum, pancreas Group C e Positive c Not evaluated Permethrin (Rusiecki et al. 2006, 2009 "
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