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

Abstract

BackgroundPermethrin is a synthetic pyrethroid insecticide widely used in agriculture, in public health, and in many U.S. homes and gardens.ObjectiveIn this study we evaluated the incidence of cancer among pesticide applicators exposed to permethrin in the Agricultural Health Study (AHS).MethodsA total of 49,093 pesticide applicators were included in this analysis of the AHS, a prospective cohort study of licensed pesticide applicators in Iowa and North Carolina. Detailed information on pesticide exposure and lifestyle factors was obtained from self-administered questionnaires completed in 1993–1997. Average length of follow-up since applicator enrollment in the cohort was 9.14 years. We used two permethrin exposure metrics: a) lifetime days applicators personally mixed or applied permethrin and b) intensity-weighted lifetime days (lifetime days weighted by estimated intensity of exposure). We used Poisson regression analysis to estimate relative risks (RRs) and 95% confidence intervals (CIs) for malignancies by tertiles of exposure.ResultsWe found no associations between permethrin and all malignant neoplasms combined, or between permethrin and melanoma, non-Hodgkin lymphoma, leukemia, or cancers of the colon, rectum, lung, or prostate. We found elevated and statistically significant risks for multiple myeloma in the highest tertiles of both lifetime exposure-days (RR = 5.72; 95% CI, 2.76–11.87) and intensity-weighted lifetime exposure-days (RR = 5.01; 95% CI, 2.41–10.42), compared with applicators reporting they never used permethrin; these results are based on only 15 exposed cases. These findings were similar across a variety of alternative exposure metrics, exposure categories, and reference groups.ConclusionsThis study found no association with most cancers analyzed. Although the suggested association with multiple myeloma was based on a small number of cases, it warrants further evaluation.

A review of pesticide exposure and cancer incidence in the agricultural health study cohort

“…examined were associated with a significant increase in overall cancer incidence (alachlor, atrazine, captan, carbaryl, carbofuran, chlorothalonil, cyanazine, dicamba, dichlorvos, fonofos, glyphosate, heptachlor, imazethapyr, malathion, metolachlor, pendimethalin, permethrin, phorate, and tri-fluralin) (Bonner et al , 2007De Roos et al 2005a;Greenburg et al 2008;Hou et al 2006;Kang et al 2008;Koutros et al 2008Koutros et al , 2009Lee et al 2004b;Lynch et al 2006;Mahajan et al 2006aMahajan et al , 2006bMahajan et al , 2007Mozzachio et al 2008;Rusiecki et al 2004Rusiecki et al , 2006Rusiecki et al , 2009Samanic et al 2006). Lung cancer.…”

“…However, the most recent study of pendimethalin exposure did not observe a significant exposure-response trend for lung cancer . Fourteen other pesticides were examined but were not associated with increased lung cancer incidence in pesticide applicators (atrazine, captan, carbaryl, chlorothalonil, cyanazine, dichlorvos, EPTC, fonofos, glyphosate, imazethapyr, malathion, permethrin, phorate, and trifluralin) (Alavanja et al 2004;Bonner et al 2007;De Roos et al 2005a;Kang et al 2008;Greenburg et al 2008;Mahajan et al 2006aMahajan et al , 2006bMahajan et al , 2007Mozzachio et al 2008;Lynch et al 2006;Rusiecki et al 2004Rusiecki et al , 2009Samanic et al 2006;van Bemmel et al 2008).…”

Increased cancer burden among pesticide applicators and others due to pesticide exposure

“…21 The cause of this excess could not yet be explained, but a separate analysis of the AHS cohort observed a statistically significant risk of multiple myeloma among pesticide applicators in the highest exposure group for the insecticide permethrin (RR, 5.72; 95% CI, 2.76-11.87 [P value for trend ¼ .01]) compared with never-users. 156 A cautious interpretation of these results is warranted because the analysis was driven by only 10 exposed cases in the highest exposure group. Positive associations between the fungicide captan (OR, 2.35; 95% CI, 1.11-3.27) and the insecticide carbaryl (OR, 1.89; 95% CI, 0.98-3.67) and multiple myeloma were observed in a recent Canadian populationbased case-control study conducted among men in 6 Canadian provinces (ie, Quebec, Ontario, Manitoba, Saskatchewan, Alberta, and British Columbia).…”

Monoclonal Gammopathy of Undetermined Significance and Smoldering Myeloma: New Insights into Pathophysiology and Epidemiology

“…5,6 Chronic antigen stimulation [7][8][9][10][11] and pesticide exposure have also been associated with an excess risk of MGUS/MM. 12,13 Recently, a large population-based study found a 2-fold increased relative risk for MM among 37,838 first-degree relatives of 13,896 MM patients (compared with 151,068 first-degree relatives of 54,365 matched controls). 14 Similarly, a 3-fold-increased relative risk for both MGUS and MM was found among 14,621 first-degree relatives of 4458 MGUS patients (compared with 58,387 firstdegree relatives of 17,505 matched controls).…”