Risk of lymphatic or haematopoietic cancer mortality with occupational exposure to animals or the public

Abstract

Background: Occupational exposure to animals or the public could result in exposure to infectious agents, which may play a role in the aetiology of lymphohaematopoietic (LH) cancers. Aims: To conduct a population based, case-control study of death certificate data from 1984 to 1998 in 24 US states in order to evaluate the risk of mortality from LH neoplasms associated with occupational exposure to animals or the public. Methods: Cases were selected as those with an underlying cause of death of non-Hodgkin's lymphoma (NHL, n = 72 589), Hodgkin's disease (HD, n = 5479), multiple myeloma (n = 35 857), or leukaemia (n = 68 598); 912 615 controls were randomly selected from all remaining deaths, frequency matched on age, sex, race, and geographic region. Results: Occupational exposure to animals was associated with modest increased risks of mortality from all four LH cancers; these associations varied by region. Occupational exposure to the public was associated with only negligible increased risk with LH cancer outcomes. Occupations involving animal exposure were predominantly agricultural, and the risks associated with employment in the livestock industry exceeded the corresponding risks associated with the crop industry for all outcomes except HD. Conclusions: Increased risks of NHL, HD, multiple myeloma, and leukaemia were associated with occupations that involved animal exposure. Regional differences in risk imply that the risks may be associated with exposure to specific livestock or farming practices. However, these associations may be confounded by other farming related exposures, such as pesticides. Because the use of death certificates to classify occupation may result in misclassification during aetiologically relevant time periods, these hypotheses should be further explored in studies with detailed information on lifetime occupation.

Occupation and the Risk of Non-Hodgkin Lymphoma

“…Four studies reported an association with NHL; seven reported no association; and none reported an inverse association. Results for employment in farming of specific crops and livestock breeding were analyzed separately: four risk estimates for crop farming (5,(26)(27)(28) and six (4,5,23,(26)(27)(28) for animal breeding (Supplementary Table S3). Only one of the studies on crop farming reported an association with NHL, whereas four of six studies on animal breeding reported an association with NHL.…”

“…Five studies (5,6,17,19,28) of school teachers published after the meta-analysis were identified (Supplementary Table S4), of which three reported an association with NHL. These five new studies were analyzed together with the 13 studies included in the meta-analysis (Table 1).…”

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

“…Occupational exposure to beef cattle was associated significantly with NHL (OR 5 1.8, 95% CI: 1.1-2.9), but no association was observed for dairy cattle (OR 5 0.9, 95% CI: 0.5-1.6). 633 Svec et al 264 reported a significant positive association between NHL and animal exposure among farming occupations (OR 5 1.25, 95% CI: 1.19-1.31) in a case-control study of death certificate data in 24 US states.…”

Multiple myeloma: A review of the epidemiologic literature

“…A significant positive association was found for farming occupations with animal exposure (OR 5 1.24, 95% CI: 1.17-1.32) in a case-control study of death certificate data from 24 US states. 85 Semenciw et al 71 evaluated farming practices in the prairie provinces of Canada in a retrospective cohort study and found no evidence of an exposure-response relationship based on the size of poultry or cattle farms; the relative risk estimates for each quartile were 1.0. Similar findings were observed in 2 recently published Canadian population-based case-control studies.…”