Non‐Hodgkin's lymphoma among asthmatics exposed to pesticides

Abstract

We conducted a pooled analysis of population-based casecontrol studies in Iowa, Minnesota and Nebraska to investigate whether asthma modifies risk of non-Hodgkin's lymphoma (NHL) associated with pesticide exposures. Cases (n ‫؍‬ 872) diagnosed with NHL from 1980 to 1986 and frequency-matched controls (n ‫؍‬ 2,381) randomly selected from the same geographic areas as the cases were included. Information on use of pesticides and history of asthma was based on interviews. Unconditional logistic regression was used to calculate ORs, adjusted for age, state and vital status. Of all subjects, 177 (45 cases, 132 controls) reported having been told by their doctor that they had asthma. Subjects with an asthma history had a nonsignificantly lower risk of NHL than nonasthmatics (OR ‫؍‬ 0.6, 95% CI 0.3-1.4), and there was no main effect of pesticide exposure (OR ‫؍‬ 1.0, 95% CI 0.8 -1.2). However, asthmatics tended to have larger ORs associated with exposure to pesticides than nonasthmatics. The OR among asthmatics was 1.8 (95% CI 1.1-3.2) for everuse of crop insecticides, 2.7 (95% CI 1.0 -7.2) for chlordane, 2.4 (95% CI 1.0 -5.7) for lindane and 3.7 (95% CI 1.3-10.9) for fonofos. Among nonasthmatics, ORs were 1.1 (0.9 -1.3), 1. Incidence and mortality rates for non-Hodgkin's lymphoma (NHL) have been increasing worldwide over the past several decades. 1 Although the reasons for this increase are not fully understood, NHL is known to be associated with a compromised immune system, particularly acquired or genetic immunodeficiencies. 2,3 Medical conditions related to more subtle immune alteration, such as asthma and other allergic conditions, have also been studied as potential risk factors for NHL. 4 -10 These reports have described a decreased risk for NHL among persons with a history of asthma or allergies, 4,5 no association 6 -8 or an increase in risk. 9,10 Exposure to pesticides has also been suggested as a possible risk factor for NHL. [11][12][13][14][15] Pesticides may increase cancer risk by altering the immune system. 16 -19 Because both asthma and pesticide exposure may change the risk of NHL by immunologic alterations, we investigated the relation between pesticide exposure, asthma and risk of NHL. MATERIAL AND METHODS Study populationWe pooled data from 2 population-based case-control studies of NHL in 3 midwestern states in the United States, which have been described in detail previously. 20,21 In Iowa and Minnesota, all newly diagnosed cases of NHL among white men aged Ն30 were ascertained from records of the Iowa State Health Registry and a special surveillance system of Minnesota hospitals and pathology laboratories from 1980 to 1983 (n ϭ 530). In Nebraska, all cases of NHL diagnosed between July 1983 and June 1986 among white men and women aged Ն21 in 45 eastern counties were identified through the Nebraska Lymphoma Study Group and area hospitals (n ϭ 346). All cases were reviewed by pathologists, and only histologically confirmed cases were included in this analysis. Controls were randomly selected from ...

Plasma polychlorobiphenyl and organochlorine pesticide level and risk of major lymphoma subtypes

“…Immunotoxicity, enzyme induction, dioxin-like effects and endocrine disrupting effects might be relevant in this regard. An interaction with viruses, such as the Epstein-Barr virus,5 7 or allergic diseases, such as asthma,33 has been suggested, but uncertainties persist as negative findings have also been published 6 12…”

Fonofos Exposure and Cancer Incidence in the Agricultural Health Study

“…Organophosphates have been associated with leukemia and other immunologically related cancers in the epidemiologic literature (Brown et al 1990; Cantor et al 1992; Clavel et al 1996; De Roos et al 2003; Lee et al 2004; Waddell et al 2001; Zahm et al 1993). The leukemogenic effects of organophosphates may be related to immune function perturbation.…”

“…Later, to evaluate specific pesticides as risk factors for NHL, Waddell et al (2001) and De Roos et al (2003) pooled three population-based case–control studies conducted in the midwestern United States and found odds ratios (ORs) for fonofos exposure of 1.7 [95% confidence interval (CI), 1.1–2.6] and 1.8 (95% CI, 0.9–3.5), respectively. Further, because NHL is associated with a compromised immune system, Lee et al (2004) pooled two of the studies to evaluate risk from pesticide exposure and asthma, a marker of immune alteration, and observed an elevated main effect for fonofos use (OR = 1.6; 95% CI, 1.0–2.4) as well as an elevated joint effect of fonofos use and asthma (OR = 3.7; 95% CI, 1.3–10.9).…”

The non-Hodgkin lymphomas: A review of the epidemiologic literature

“…44 A significantly increased risk of extranodal NHL was reported for malathion (OR 5 3.52, 95% CI: 1.24-10.0), however. 44 Lee et al 51 reported non-significantly increased relative risks of NHL in association with several individual pesticide exposures among asthmatics compared to non-asthmatics.…”