Poultry and livestock exposure and cancer risk among farmers in the agricultural health study

Abstract

Purpose The purpose of this study is to evaluate cancer risk associated with raising animals as commodities, which is associated with a variety of exposures, such as infectious agents and endotoxins. Methods Information was available for 49,884 male farmers in the Agricultural Health Study, who reported livestock and poultry production at enrollment (1993–1997). Cancer incidence data were obtained through annual linkage to state registries. Using Poisson regression analyses, we evaluated whether the number and type of animals raised on the farm impacted cancer risk. Results Overall, 31,848 (63.8%) male farmers reported raising any animals. Lung cancer risk decreased with increasing number of livestock on the farm (p-trend=0.04) and with raising poultry (Relative Risk (RR)= 0.6; 95% Confidence Interval (CI): 0.4–0.97). Raising poultry was associated with an increased risk of colon cancer (RR=1.4; 95% CI: 0.99–2.0) with further increased with larger flocks (p-trend=0.02). Risk of non-Hodgkin lymphoma was also elevated in those who raised poultry (RR=1.6; 95% CI: 1.0–2.4), but there was no evidence of increased risk with larger flocks (p-trend=0.5). Raising sheep was associated with a significantly increased risk of multiple myeloma (RR=4.9; 95% CI: 2.4–12.0). Performing veterinary services increased the risk of Hodgkin lymphoma (RR=12.2; 95% CI: 1.6–96.3). Conclusions We observed an inverse association between raising poultry and livestock and lung cancer risk and some evidence of increased risk of specific lymphohematopoietic malignancies with specific types of animals and performing veterinary services. Further research into associations between raising animals and cancer risk should focus on identification of etiologic agents.

Non-Hodgkin Lymphoma and Occupational Exposure to Agricultural Pesticide Chemical Groups and Active Ingredients: A Systematic Review and Meta-Analysis

“…Farmers experience low overall mortality but high rates of some cancers; this suggests that some or several agricultural exposures may be key determinants [5,6]. Indeed, positive associations between NHL and farm related exposures, including pesticides, fertilizers, chemicals, animals, viruses, and endotoxin, have been observed previously [3,5,7]. However, the wide variety of chemical and microbial exposures that occur simultaneously in agricultural production makes disentangling the effects of these factors challenging.…”

Acute myeloid leukemia risk by industry and occupation

“…This is consistent with a previous study by Beth-waite et al ., which found an increased risk for AML among workers employed in an abattoir [33], but not among butchers or meat packers who worked in retail or wholesale, nor among cattle, dairy or sheep farmers [33]. Furthermore, the Agricultural Health Study (AHS) did not find an elevated leukemia risk among farmers who worked with various types of livestock; however, findings specific for AML were not reported [41]. It should be noted that laboratory studies have found little evidence that animal viruses infect human cells [33,42].…”

Farm residence and lymphohematopoietic cancers in the Iowa Women׳s Health Study

“…The increased AML risk observed among women on farms, the 2-fold elevated risk among women in rural residences that were not farms, and the lack of association with crop acreage suggest that farm exposures other than crop pesticides may be important AML risk factors. For example, links between animal husbandry and increased leukemia risk have been reported in the AHS (Beane Freeman et al, 2012) and by others (Svec et al, 2005), though AML was not specifically examined. The etiologic pathway for animal exposures in the development of these cancers has not been clearly elucidated, but is hypothesized to involve infectious agents (Svec et al, 2005).…”