Lung Cancer Risk in Workers in the Meat and Poultry Industries – A Review

Abstract

Laboratory and in vivo studies in primates, and serological evidence in humans, indicate that food animal oncogenic viruses show potential for causing cancer in humans. However, until fairly recently, supporting analytic epidemiologic studies have been lacking and have concentrated on lung cancer. We conducted an extensive Medline search and reviewed 60 studies investigating lung cancer risk in highly exposed workers in the meat and poultry industries. The overwhelming majority of studies of different designs (including all the cohort mortality and cancer incidence studies) indicate at least a 30% excess risk of lung cancer in meat and poultry plant workers, even after controlling for smoking. Evidence points to food animal oncogenic microorganisms as one of the main causes. This has important public health implications because the general population is also widely exposed. Studies carried out thus far have not had sufficient statistical power to investigate other potentially carcinogenic exposures within the industries. Thus, large studies that can adequately control for occupational and non-occupational confounding factors are needed, so that the possible role of food animal oncogenic viruses in the occurrence of human lung cancer can be clearly defined.

Occupational exposure to endotoxins and lung cancer risk: results of the ICARE Study

“…The sector of plant cultivation was generally included in crop farming in the above-mentioned articles. Most epidemiological studies of lung cancer in meat workers provide evidence of a positive association between exposure to meat aerosols and lung cancer, as suggested by our data 29. Association between the wood industry and lung cancer is still a source of debate, and a recent meta-analysis was inconclusive 30.…”

Lack of Evidence That Avian Oncogenic Viruses Are Infectious for Humans: A Review

“…Johnson and Choi (69) chose not to run formal meta-analysis and gave several reasons. Some of the reasons imply that Johnson and Choi (69) do not accept the role meta-analysis can play in formally identifying and quantifying sources of heterogeneity or the manners in which alternative designs or studies of different perceived validity can be incorporated (20).…”

“…in a single meta-analysis; this was another reason given to avoid meta-analysis. Nevertheless, one can still run meta-analyses stratified on the more common effect measurements, and Johnson and Choi (69) included at least 42 studies in their review, so they could have run a meta-analysis on those. Also, one can sometimes go to the original papers and find enough data to allow calculation of alternative effect measures.…”

“…Also, one can sometimes go to the original papers and find enough data to allow calculation of alternative effect measures. No mention was made in Johnson and Choi (69) of whether this was attempted or how many studies might have had the same type of effect measure.…”

“…In a recent review paper, Tischer and Osterrieder (140) also concluded that there is no formal proof or even likelihood of infection of humans with MDV. However, based on recent epidemiological studies, concerns have once more been raised that MDV and avian retroviruses can cause cancer in humans (33,48,69,72) and that MDV or the closely related herpes virus of turkeys (HVT), one of the MDV vaccine strains, may be the cause of multiple sclerosis (MS) (21, 88,89,90,92,93). In this paper we will first analyze examples of the epidemiological evidence that these viruses are causative agents for human cancer, followed by description of the relevant key characteristics of ALV, REV, and MDV.…”