Hodgkin Lymphoma and Pesticides Exposure in Men: A Canadian Case-Control Study

Abstract

The objective of this study was to investigate the putative associations of specific pesticides with Hodgkin lymphoma. A population-based, case-control study of Hodgkin lymphoma was conducted among males in six regions of Canada. Data were collected by a mailed questionnaire followed by a telephone interview to obtain detailed exposures data for those reporting ≥ 10 hours per year of pesticide exposure. Conditional logistic regression was used to fit statistical models. Comparisons of 316 Hodgkin lymphoma cases and 1506 controls identified several factors as predictors for increased Hodgkin lymphoma risk: family history of cancer, exposure to the insecticide chlorpyrifos [OR (95% CI) = 1.19 (1.03, 1.37)], and previous diagnosis of acne or shingles. The increased risk of developing Hodgkin lymphoma detected among Canadian men who used chlorpyrifos must be interpreted cautiously; however the strength of its association indicates that it requires investigation in other populations.

Common infection-related conditions and risk of lymphoid malignancies in older individuals

“…Because of limited sample size, we were unable to investigate infection claims in a longer time frame preceding lymphoma diagnosis, but it has been suggested that lymphoma risk is restricted to the first 10 years since infection onset (Tavani et al , 2000). We observed similar associations between herpes zoster and DLBCL and FL, supporting previous reports in some (Karunanayake et al , 2012; Liu et al , 2012) but not all studies (Cartwright et al , 1988; Becker et al , 2012). Given the timing of these associations, it is possible that herpes zoster infection is a marker of an immunocompromised state many years before diagnosis or that it instigates a decline in cell-mediated immunity (Liu et al , 2012).…”

“…Exposure status was not limited by recall bias inherent in case–control studies (Cartwright et al , 1988; La Vecchia et al , 1992; Tavani et al , 2000; Chang et al , 2005; Becker et al , 2012; Karunanayake et al , 2012; Liu et al , 2012), although the use of claims data, instead of diagnostically confirmed infections, means that misclassification of exposure status is possible. This misclassification would be unlikely to be differential in nature, especially for claims many years before lymphoma diagnosis; however, overdiagnosis of infections, such as cellulitis, is possible.…”

“…This misclassification would be unlikely to be differential in nature, especially for claims many years before lymphoma diagnosis; however, overdiagnosis of infections, such as cellulitis, is possible. As both inpatient and outpatient claims were incorporated into the study, we were able to investigate a broader range of common infection-related conditions than previous studies (Cartwright et al , 1988; Doody et al , 1992; La Vecchia et al , 1992; Tavani et al , 2000; Chang et al , 2005; Koshiol et al , 2011; Karunanayake et al , 2012; Liu et al , 2012). Despite this strength, infections requiring few physician visits, such as the common cold, are likely to be underestimated.…”

“…Genetic variation of genes involved in the innate immune response, including tumour necrosis factor receptor-associated factor, receptor-interacting serine-threonine kinase 3, BAT2, Toll-like receptor 6 (Cerhan et al , 2007) and Beta-Defensin 126 (Hu et al , 2013), have been associated with an increased risk of NHL and have a role in infection recognition and control. Chronic antigenic stimulation has been postulated as a potential mechanism for lymphomagenesis (Hjalgrim and Engels, 2008), with acute, community-acquired infections potentially playing a role (Cartwright et al , 1988; La Vecchia et al , 1992; Tavani et al , 2000; Engels et al , 2004; Chang et al , 2005; Koshiol et al , 2011; Becker et al , 2012; Karunanayake et al , 2012; Liu et al , 2012). …”

Chlorpyrifos: pollution and remediation

“…Children exposed to higher chlorpyrifos levels are significantly more likely to experience psychomotor development index and mental development index delays, attention problems, attention deficit or hyperactivity disorder, and pervasive developmental disorder problems (Rauh et al 2006). The carcinogenicity of chlorpyrifos is not confirmed in human; yet, there are a considerable number of epidemiological studies indicating increased risk of various cancers in pesticide applicators, especially colorectal (Lee et al 2007), prostate (Alavanja et al 2003), breast (Engel et al 2005), lymphoma (Karunanayake et al 2012), hematopoietic, leukemia, and brain cancers (Lee et al 2004). There is evidence of immune toxicity, including the effects on lymphocytes (Blakley et al 1999), thymocytes (Prakash et al 2009), T cells (Thrasher et al (Rowsey and Gordon 1999), and autoimmunity.…”