Increased risks of soft tissue sarcoma, malignant lymphoma, and acute myeloid leukemia in abattoir workers

Association between occupational exposures and sarcoma incidence and mortality: systematic review and meta-analysis

BACKGROUND

Sarcomas are a rare and heterogeneous group of tumors originating from mesenchymal or connective tissue. They represent less than 1% of all adult cancers. The etiology and epidemiology of sarcomas remain understudied and poorly understood. The main objective of our study was to systematically assess the association between various occupational exposures and risk of sarcomas.

METHODS

We performed a systematic literature search using the PubMed, Scopus, EMBASE and Cochrane databases to identify relevant cohort and case-control studies. A meta-analysis method was applied on the incidence and mortality outcomes where the estimate with 95% confidence interval (CI) was obtained.

RESULTS

We included a total of 50 publications in our systematic review and 35 in meta-analysis. For exposures to phenoxy herbicides and chlorophenols, the pooled odds ratio (OR) for sarcoma was 1.85 (95% CI: 1.22, 2.82), based on 16 studies with 2254 participants, while the pooled standardized mortality ratio was 40.93 (95% CI 2.19, 765.90), based on 4 cohort studies with 59,289 participants. For exposure to vinyl chloride monomers the pooled risk ratios for angiosarcoma of the liver and other STS were 19.23 (95% CI 2.03, 182.46) and 2.23 (95 CI 1.55, 3.22) respectively based on 3 cohort studies with 12,816 participants. Exposure to dioxins was associated with an increased STS mortality; the pooled standardized mortality ratio was 2.56 (95% CI 1.60, 4.10) based on 4 cohort studies with 30,797 participants. Finally, woodworking occupation was associated with an increased risk of STS with the pooled OR of 2.16 (95% CI 1.39, 3.36).

CONCLUSIONS

Our findings suggest a positive association between higher exposure to dioxins and increased mortality from STS, between cumulative exposure to vinyl chloride monomers and increased mortality from angiosarcoma of the liver and STS, and between woodworking occupation and STS incidence. These findings were all statistically significant.

Research at the interface between human and veterinary health

Epidemiology is currently undergoing changes in its underlying philosophy and approach, as a result of the rapid global changes which are transforming the world in which epidemiologists live and work. This necessitates a multidisciplinary "population approach" involving "multilevel thinking" about the determinants of disease. These issues are of relevance to the interface between human and animal epidemiology, which has received considerable attention in recent years, particularly as a result of the arrival of H1N1 influenza, and the increasingly obvious need for coordinated systems of surveillance for human and animal infectious diseases. However, the need for coordination between human and veterinary epidemiology is broader than that, and there is no need to restrict the "one world one health" concept to communicable disease. In the current paper we will therefore consider the interface between human and animal health for the study of non-communicable disease, particularly those involving occupational and environmental risk factors. These issues are illustrated with two examples: one involving environmental health (asthma); and one involving occupational health (cancer). We will also discuss the potential to use animal health data as indicators for human environmental health risks.

Evaluation of the human host range of bovine and porcine viruses that may contaminate bovine serum and porcine trypsin used in the manufacture of biological products

Current U.S. requirements for testing cell substrates used in production of human biological products for contamination with bovine and porcine viruses are U.S. Department of Agriculture (USDA) 9CFR tests for bovine serum or porcine trypsin. 9CFR requires testing of bovine serum for seven specific viruses in six families (immunofluorescence) and at least 2 additional families non-specifically (cytopathicity and hemadsorption). 9CFR testing of porcine trypsin is for porcine parvovirus. Recent contaminations suggest these tests may not be sufficient. Assay sensitivity was not the issue for these contaminations that were caused by viruses/virus families not represented in the 9CFR screen. A detailed literature search was undertaken to determine which viruses that infect cattle or swine or bovine or porcine cells in culture also have human host range [ability to infect humans or human cells in culture] and to predict their detection by the currently used 9CFR procedures. There are more viruses of potential risk to biological products manufactured using bovine or porcine raw materials than are likely to be detected by 9CFR testing procedures; even within families, not all members would necessarily be detected. Testing gaps and alternative methodologies should be evaluated to continue to ensure safe, high quality human biologicals.

Leukaemia and occupation: a New Zealand Cancer Registry-based case-control Study

BACKGROUND

To examine the association between occupation and leukaemia.

METHODS

We interviewed 225 cases (aged 20-75 years) notified to the New Zealand Cancer Registry during 2003-04, and 471 controls randomly selected from the Electoral Roll collecting demographic details, information on potential confounders and a comprehensive employment history. Associations between occupation and leukaemia were analysed using logistic regression adjusted for gender, age, ethnicity and smoking.

RESULTS

Elevated odds ratios (ORs) were observed in agricultural sectors including horticulture/fruit growing (OR: 2.62, 95% confidence interval (CI): 1.51, 4.55), plant nurseries (OR: 7.51, 95% CI: 1.85, 30.38) and vegetable growing (OR: 3.14, 95% CI: 1.18, 8.40); and appeared greater in women (ORs: 4.71, 7.75 and 7.98, respectively). Elevated ORs were also observed in market farmers/crop growers (OR: 1.84, 95% CI: 1.12, 3.02), field crop/vegetable growers (OR: 3.98, 95% CI: 1.46, 10.85), market gardeners (OR: 5.50, 95% CI: 1.59, 19.02), and nursery growers/workers (OR: 4.23, 95% CI: 1.34, 13.35); also greater in women (ORs: 3.48, 7.62, 15.74 and 11.70, respectively). These elevated ORs were predominantly for chronic lymphocytic leukaemia (CLL). Several associations persisted after semi-Bayes adjustment. Elevated ORs were observed in rubber/plastics products machine operators (OR: 3.76, 95% CI: 1.08, 13.08), predominantly in plastic product manufacturing. CLL was also elevated in tailors and dressmakers (OR: 7.01, 95% CI: 1.78, 27.68), cleaners (OR: 2.04, 95% CI: 1.00, 4.14) and builder's labourers (OR: 4.03, 95% CI: 1.30, 12.53).

CONCLUSIONS

These findings suggest increased leukaemia risks associated with certain agricultural, manufacturing, construction and service occupations in New Zealand.

Unpasteurized milk consumption and subsequent risk of cancer

Concerns have been raised regarding the possible adverse health effects of consumption of unpasteurized milk and risk of cancer. We examined the association of self-reported intake of unpasteurized milk with subsequent risk of cancer in a large population-based cohort study. The Iowa Women's Health Study is a prospective cohort study of 55-69 year old women at baseline in 1986. Of the 41,836 women in the cohort at baseline, 22,808 cancer-free women completed the fourth follow-up questionnaire in 1997. Risk ratios (RR) and 95% confidence intervals (CI) were calculated using Cox proportional hazards regression analysis. Reported intake of unpasteurized milk was high: 59.2% consumed only as a child, 2.5% consumed only as an adult, and 16.5% consumed as a child and an adult. A total of 2,379 cancers were identified in the cohort at risk. Overall, the age-adjusted risk of cancer was lower among women who reported consumption of unpasteurized milk only as a child (RR = 0.90, 95% CI: 0.82-0.99) or as a child and an adult (RR = 0.85; 95% CI: 0.75-0.97). Adjustment for confounding factors attenuated these associations (RR = 0.92, 95% CI: 0.83-1.02 for consumption only as a child, and RR = 0.91; 95% CI: 0.79-1.04 for consumption as a child and an adult). These data suggest that consumption of unpasteurized milk does not increase risk of cancer.

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

The non-Hodgkin lymphomas (NHL) are a heterogeneous group of B-cell and T-cell neoplasms that arise primarily in the lymph nodes. NHL incidence rates in the US doubled between about 1970 and 1990, and stabilized during the 1990s. NHL accounts for approximately 3.4% of cancer deaths in the US. Although some of the observed patterns in NHL have been related to HIV/AIDS, these conditions cannot fully explain the magnitude of the changes; neither do changes in classification systems nor improved diagnostic capabilities. Studies of occupational and environmental exposures (e.g., pesticides, solvents) have produced no consistent pattern of significant positive associations. Inverse associations with ultraviolet radiation exposure and alcohol and fish intake, and positive associations with meat and saturated fat intake have been reported in several studies; additional studies are needed to confirm or refute these associations. Family history of NHL or other hematolympho-proliferative cancers and personal history of several autoimmune disorders are associated with increased risk of NHL, but are not likely to account for a large proportion of cases. HIV and other infectious agents, such as human herpesvirus 8 and Epstein-Barr, appear to be associated with differing types of NHL, such as some B-cell lymphomas. Future epidemiologic studies should evaluate associations by NHL type, enhance exposure information collected, and elucidate factors that may identify susceptible (or resistant) subpopulations because of genetic, immunologic or other characteristics. The extent to which the etiology of NHL types may differ is important to resolve in ongoing and future studies.

Occupation and the risk of non-Hodgkin lymphoma

Although thus far no occupational agents have been classified as established causes of non-Hodgkin lymphoma (NHL), employment as a farmer, teacher, dry cleaner, meat worker, printer, or wood worker has been associated with elevated risk in the peer-reviewed literature. We conducted several meta-analyses to assess risk in these occupations and industries from articles published in MEDLINE up to August 1, 2006. The summary risk estimates suggest a homogeneous excess risk for NHL among workers in the printing industry [relative risk (RR), 1.86; 95% confidence interval (95% CI), 1.37-2.52] and wood workers (RR, 1.15; 95% CI, 1.00-1.31). Considerable heterogeneity but elevated risks were found for farmers (RR, 1.11; 95% CI, 1.05-1.17), especially in animal husbandry (RR, 1.31; 95% CI, 1.08-1.60), and teaching (RR, 1.47; 95% CI, 1.34-1.61). An increased risk was absent for employment in the meat processing industry (RR, 0.99; 95% CI, 0.77-1.29). These results suggest that although excess risk is found for employment in the printing industry, wood processing industry, teaching, and farming, it is unlikely that occupation represents a major risk factor for NHL in most populations. At present, no conclusive evidence of causal relations between occupations and increased NHL risk exists; this can be ascribed to methodologic problems in studying the link between NHL risk and occupation, including heterogeneity of disease and exposure circumstances and low statistical power. Implementing state-of-the-art exposure assessment technologies, including biomarker-based assessment, and aiming to identify susceptible subgroups can increase the statistical power enough to analyze etiologically relevant NHL subtypes and provide clues on possible causal agents in future studies. These goals can be best attained within the framework of large-scale, international collaborative projects.

Occupational exposure to meat and risk of lymphoma: A multicenter case-control study from Europe

Several studies have suggested an increased risk of lymphoma among workers exposed to meat, without conclusive evidence. We conducted a multicenter case-control study during 1998-2004 in the Czech Republic, France, Germany, Ireland, Italy and Spain, including 2,007 cases of non-Hodgkin lymphoma, 339 cases of Hodgkin lymphoma and 2,462 controls. We collected detailed information on occupational history and assessed exposure to meat in general and several types of meat via expert assessment of the questionnaires. The odds ratio (OR) of non-Hodgkin lymphoma for ever occupational exposure to meat was 1.18 (95% confidence interval [CI] 0.95-1.46), that for exposure to beef meat was 1.22 (95% CI 0.90-1.67), and that for exposure to chicken meat was 1.19 (95% CI 0.91-1.55). The ORs were higher among workers with longer duration of exposure. An increased risk among workers exposed to beef meat was mainly apparent for diffuse large B-cell lymphoma (OR 1.49, 95%CI 0.96-2.33), chronic lymphocytic leukemia (OR 1.35, 95% CI 0.78-2.34) and multiple myeloma (OR 1.40, 95%CI 0.67-2.94). The latter 2 types were also associated with exposure to chicken meat (OR 1.55, 95% CI 1.01-2.37, and OR 2.05, 95%CI 1.14-3.69). Follicular lymphoma and T-cell lymphoma, as well as Hodgkin lymphoma did not show any increase in risk. Occupational exposure to meat does not appear to represent an important risk factor of lymphoma, although an increased risk of specific types of non-Hodgkin lymphoma cannot be excluded.

Cancer mortality among butchers: a 24-state death certificate study

OBJECTIVE

The objective of this study was to document cancer mortality among American butchers.

METHODS

Death certificates collected in 24 American states were used to calculate mortality odds ratios (ORs) and their confidence intervals (CIs) for 18,639 butchers.

RESULTS

Butchers experienced an increased mortality of cancer of the oral cavity (OR, 1.40; 95% CI = 1.09-1.81), esophagus (OR, 1.19; 95% CI = 1.01-1.40), pharynx (OR, 1.22; 95% CI = 0.91-1.64), and larynx (OR, 1.19; 95% CI = 0.92-1.54), as well as a reduced mortality from melanoma (OR, 0.70; 95% CI = 0.52-0.94), non-Hodgkin lymphoma (OR, 0.82; 95% CI = 0.69-0.97), and breast cancer (OR, 0.76; 95% CI = 0.58-0.99).

CONCLUSIONS

It is likely that occupational exposures experienced by butchers have contributed to the increased risk of cancers of the oral cavity and esophagus.

Virus target cell conditioning model to explain some epidemiologic characteristics of childhood leukemias and lymphomas

Frequent infections in early childhood, whole-day care and a socially unprivileged environment have been reported as protective factors for childhood leukemias and lymphomas. Conversely, a protected social environment, higher level of education and growing up in families with a low number of children are considered as risk factors. Additional risk factors involve agricultural occupation of the parents and exposure to several other occupational factors. These data led to a number of hypotheses that attempted to explain the epidemiologic observations; however, a number of questions are still open. Here we propose a new concept that could explain most of the epidemiologic characteristics. This concept is based on the assumption that persistent infections with TT virus-like agents increase the risk for specific chromosomal translocations. This risk should correlate with the viral load. Interferon induction by intermittent infections should reduce the viral load and thus decrease the risk for chromosomal modifications. Some virologic observations in support of this model are presented.

Mortality and cancer incidence in New Zealand meat workers

AIMS

To ascertain whether there is an increased risk of cancers of the lung and lymphohaematopoietic tissue in workers employed in the New Zealand meat processing industry, and to identify exposures associated with any increased risks.

METHODS

A cohort of 6647 individuals assembled from personnel records from three plants was followed from 1988 until 2000. The observed number of deaths and cancer registrations was compared with expected numbers using five year age and gender specific rates for the New Zealand population. Subgroup analyses evaluated the effect of duration of exposure to selected agents, based on job titles and departments.

RESULTS

Vital status was determined for 84% of the cohort, and 92% of the total possible person-years. Mortality from all causes and all cancers was increased, and there was a significant excess of lung cancer. There were significant trends of increasing risk of lung and lymphohaematopoietic cancer with increasing duration of exposure to biological material.

CONCLUSIONS

Excess risks were observed for mortality from all causes, all cancers, and lung cancer. Although the increased risk of lung cancer may be partly due to confounding by smoking, it is unlikely to be entirely due to this cause. Furthermore, the dose-response relation observed for lung cancer suggests the effect is related to exposure to biological material contained in animal urine, faeces, and blood. Although numbers were small, the risk of lymphohaematopoietic cancer was also associated with increasing duration and level of exposure to biological material.

Agricultural risk factors for t(14;18) subtypes of non-Hodgkin's lymphoma

The t(14;18) translocation is a common somatic mutation in non-Hodgkin's lymphoma (NHL) that is associated with bcl-2 activation and inhibition of apoptosis. We hypothesized that some risk factors might act specifically along t(14;18)-dependent pathways, leading to stronger associations with t(14;18)-positive than t(14;18)-negative non-Hodgkin's lymphoma. Archival biopsies from 182 non-Hodgkin's lymphoma cases included in a case-control study of men in Iowa and Minnesota (the Factors Affecting Rural Men, or FARM study) were assayed for t(14;18) using polymerase chain reaction amplification; 68 (37%) were t(14;18)-positive. We estimated adjusted odds ratios (OR) and 95% confidence intervals (CI) for various agricultural risk factors and t(14;18)-positive and -negative cases of non-Hodgkin's lymphoma, based on polytomous logistic regression models fit using the expectation-maximization (EM) algorithm. T(14;18)-positive non-Hodgkin's lymphoma was associated with farming (OR 1.4, 95% CI = 0.9-2.3), dieldrin (OR 3.7, 95% CI = 1.9-7.0), toxaphene (OR 3.0, 95% CI = 1.5-6.1), lindane (OR 2.3, 95% CI = 1.3-3.9), atrazine (OR 1.7, 95% CI = 1.0-2.8), and fungicides (OR 1.8, 95% CI = 0.9-3.6), in marked contrast to null or negative associations for the same self-reported exposures and t(14;18)-negative non-Hodgkin's lymphoma. Causal relations between agricultural exposures and t(14;18)-positive non-Hodgkin's lymphoma are plausible, but associations should be confirmed in a larger study. Results suggest that non-Hodgkin's lymphoma classification based on the t(14;18) translocation is of value in etiologic research.

Mortality among male licensed pesticide users and their wives

BACKGROUND

We evaluated the mortality pattern of male licensed pesticide users and their wives in central Italy.

METHODS

The cohort consisted of 2978 male farmers licensed for buying and handling toxic pesticides during the period 1971-1973 and 2586 farmers' wives. The Standardized Mortality Ratio (SMRs) and their 95% Confidence Intervals (95% CI) were computed on the basis of regional death rates.

RESULTS

We found a lower than expected overall and cancer mortality. Non-Hodgkin's lymphoma was increased among women (SMR = 2.29, 0.62-5.86) but not in male farmers (SMR = 0.90, 0.24-2.30), while both sexes were characterized by an increased risk of leukemia (men: SMR = 1.44, 0.69-2.64; women: SMR = 2.41, 1.04-4.76), mainly due to myeloid leukemia (men: SMR = 2.43, 0.98-5.00; women: SMR = 3.14, 1.02-7.33).

CONCLUSIONS

Men and women tend to share the same mortality profile. The statistically significant increase of leukemia with a threefold increased risk of the myeloid subtype only among women suggests that different pattern of exposure or biological differences between genders should be considered in evaluating health risks in agricultural settings.

Occupational exposures, animal exposure and smoking as risk factors for hairy cell leukaemia evaluated in a case-control study

To evaluate occupational exposures as risk factors for hairy cell leukaemia (HCL), a population-based case-control study on 121 male HCL patients and 484 controls matched for age and sex was conducted. Elevated odds ratio (OR) was found for exposure to farm animals in general: OR 2.0, 95% confidence interval (CI) 1.2-3.2. The ORs were elevated for exposure to cattle, horse, hog, poultry and sheep. Exposure to herbicides (OR 2.9, CI 1.4-5.9), insecticides (OR 2.0, CI 1.1-3.5), fungicides (OR 3.8, CI 1.4-9.9) and impregnating agents (OR 2.4, CI 1.3-4.6) also showed increased risk. Certain findings suggested that recall bias may have affected the results for farm animals, herbicides and insecticides. Exposure to organic solvents yielded elevated risk (OR 1.5, CI 0.99-2.3), as did exposure to exhaust fumes (OR 2.1, CI 1.3-3.3). In an additional multivariate model, the ORs remained elevated for all these exposures with the exception of insecticides. We found a reduced risk for smokers with OR 0.6 (CI 0.4-1.1) because of an effect among non-farmers.

Chronic lymphocytic leukaemias and non-Hodgkin's lymphomas by histological type in farming-animal breeding workers: a population case-control study based on a priori exposure matrices

OBJECTIVES

A population based case-control study was conducted in a highly agricultural area in Italy to investigate the association between chronic lymphocytic leukaemias (CLLs) and non-Hodgkin's lymphomas (NHLs), and subtypes, and exposure to pesticides in farming-animal breeding workers.

METHODS

187 cases of CLLs and NHLs and 977 population controls were interviewed on medical, residential, family, and occupational history. Detailed information was collected about cultivated crops and animals bred from subjects who worked in farming and animal breeding. Information on crop diseases and pesticides used (and their quantity and duration) was also obtained. A priori job-exposure matrices were applied when a crop disease was reported, estimating the most probable pesticide and, when possible, an estimate of the cumulative dose. Odds ratios (ORs) were calculated by unconditional logistic analysis with adjustment for relevant confounders in farmers who bred animals and in farmers alone, for the main crops, types of animals, and pesticides categories. First recall and then the matrices were used for defining exposure, as it affected CLLs and NHLs and then separately on CLLs and low grade NHLs. Finally, the dose-response was investigated for those pesticides which had shown some association.

RESULTS

No variable under study was associated with work in farming alone. In farming and animal breeding, no crop or animal showed an association with CLLs and NHLs when adjusted by exposure during childhood to farming and animal breeding (an indicator of life in a farming and animal breeding environment before the age of 13, which behaved as an independent risk variable). A non-significant association was found with stannates, arsenates, phosphates, and dichloro-diphenyl-trichloroethane (DDT) based on recall, and for stannates, arsenates, and DDT after the application of the matrices. When CLLs together with low grade NHLs were considered, the association with insecticides in general, carbamates, and phosphates became significant according to personal recall (ORs and 95% confidence intervals (95% CIs) 2.46, 1.07-5.63; 3.08, 1.05-9.00; 2.97, 1.28-6.91, respectively). The application of the matrices also showed a risk of borderline significance for stannates and dithiocarbamates. A significant dose-response effect was found for phosphates (for logarithmic unit increase, OR 1.17, 95% CI 1.00-1.57); a strong trend for stannates and carbamates did not reach significance.

CONCLUSION

The association of CLLs and NHLs with work in farming-animal breeding is partially explained by exposure to pesticides-namely insecticides (carbamates, phosphates, and DDT) and stannates-possibly related to their use in animal breeding. The association is limited to cases of CLL and low grade NHL. The independent effect of the variable exposure during childhood suggests that early exposures, including possible contact with animals, may play a part in the pathogenic process of these neoplasms.

United States non-Hodgkin's lymphoma surveillance by occupation 1984-1989: a twenty-four state death certificate study

Death certificates from 23,890 male and female non-Hodgkin's lymphoma (NHL) cases and 119,450 noncancer controls from 24 states for the period 1984-1989 were used to generate hypotheses regarding occupational associations. Cases were frequency matched by age, race, and gender with five controls per case. Odds ratios were calculated for 231 industries and 509 occupations. Significant associations were observed for a variety of white-collar professionals (i.e., real estate agents, secretaries, bookkeepers, teachers, postal employees, business agents, engineers, chemists, and medical professionals) and blue-collar occupations (i.e., firefighters, farm managers, aircraft mechanics, electronic repairers, mining machine operators, and crane and tower operators).

Chronic lymphocytic leukaemias and non-Hodgkin's lymphomas by histological type in farming-animal breeding workers: a population case-control study based on job titles

OBJECTIVES

A population based case-control study was conducted in a highly agricultural area in the north east of Italy to evaluate the association between farming and animal breeding and the risk of developing non-Hodgkin's lymphoma (NHL) and chronic lymphocytic leukaemia (CLL).

METHODS

Occupational histories and other data were collected by personal interview on 164 NHLs, 23 CLLs, diagnosed in 1988-90, and on 977 controls. This paper only reports the results of the analysis relative to the coding of job titles through the modified International Labour Office (ILO) classification. Estimates of odds ratios (ORs) for occupational variables were calculated, after adjustment for sex, age, altitude of municipality, first degree familiarity, and previous Herpes zoster infection.

RESULTS

From the analysis of the most frequent occupational categories, no occupation showed a significantly high risk. When the two job titles farmers only and farmer-breeders who are also involved in animal breeding are classified within the extremely varied occupation of agriculture or animal-breeding or fishing, a high risk for NHLs and CLLs is seen in the farmer-breeders (OR 1.79, 95% CI 1.22 - 2.63). Analyses according to histological type show that the risks are concentrated in CLLs and in low grade NHLs. No effect or trend by period at work or duration of employment in farming and animal breeding was found.

CONCLUSION

Subjects working in agriculture associated with animal breeding are at high risk of NHL/CLLs, particularly CLLs and low grade NHLs. This finding could be related to the use of chemicals in agriculture or to exposure to animal transmitted diseases or specific chemicals used in animal breeding.

Antimicrobial antibodies in Danish slaughterhouse workers and greenhouse workers

As a consequence of contact with animals and animal products slaughterhouse workers might be at risk of infection with pathogenic microorganisms. This hypothesis has been supported by some earlier studies. In this study 217 slaughtermen and a control group of 113 greenhouse workers were investigated for the prevalence of serum antibodies to Toxoplasma gondii, Campylobacter jejuni (IgA and IgG), Yersinia enterocolitica types 3 and 9, Yersinia pseudotuberculosis types I, II, III, IV, and V, Salmonella typhi, Salmonella paratyphi, Salmonella enteritidis, Salmonella typhimurium, and Borrelia burgdorferi. No significant differences were found concerning either frequency of positive tests or magnitude of titers. The prevalence of toxoplasma antibodies was remarkably high in both groups.

Mortality and incidence of cancer among a cohort of self employed butchers from Geneva and their wives

To investigate whether specific cancers are associated with the occupation of butcher, as has been reported from other countries, a historical prospective cohort study was undertaken. The cohort consisted of all self employed butchers (n = 552) and pork butchers (n = 310) born since 1880 who set up a shop in the canton of Geneva from 1901 to 1969, and of their wives (n = 887). The study group was followed up from 1901 to 1990 for general mortality, from 1942 to 1990 for cause specific mortality, and from 1970 to 1989 for incidence of cancer. There was no trace of 45 men (5%) and 52 women (6%). Compared with the general population of the canton of Geneva, butchers and pork butchers experienced a significant increase, taking into account 15 years of latency, in mortality from all causes (observed deaths (Obs) 540, expected deaths (Exp) 445.5, standardised mortality ratio (SMR) 121, 90% confidence interval (90% Cl) 113-130). There were significant excesses in incidence and mortality from colorectal cancer, cancer of the prostate, and all malignant neoplasms, and in incidence of cancer of the liver. The risk of lung cancer was significantly increased among pork butchers (SMR 176, 90% Cl 114-262; standardised incidence ratio (SIR) 231, 90% Cl 137-368) but not among butchers (SMR 92, 90% Cl 59-138; SIR 113, 90% Cl 67-179). There was also a significant increase in mortality from cancer of the larynx among butchers. For non-malignant causes of death significant excesses were found among all men for ischaemic heart disease, motor vehicle accidents, and cirrhosis of the liver. Analysis of subgroups showed a cluster of deaths from leukaemia among older butchers born between 1880 and 1899 (Obs 5, Exp 0.6, p < 0.0001). Exposure of pork butchers to polycyclic aromatic hydrocarbons during meat smoking, which was assessed in a contemporary study, might have contributed to their increased risk of lung cancer. The possible role of other factors, especially cigarette smoking, nitrosamines, and oncogenic viruses was discussed. Moreover, there was evidence from another contemporary study that butchers and pork butchers ate more animal fat, and probably more animal protein, than the average male population of Geneva. These results suggest that dietary factors could be implicated in the excesses of colorectal cancer, cancer of the prostate, and ischaemic heart disease. An increased risk for alcohol abuse might explain the excesses of liver cirrhosis, cancer of the liver, cancer of the larynx and motor vehicle accidents. Among all wives overall mortality was similar to that expected (SMR 100, 90% Cl 93-108) and there was no significant excess risk for any specific cancer nor for any non-malignant cause of death. Results for cancer of the cervix uteri, especially among subgroups, suggest an increased risk consistent with previous findings from other countries.

Some occupational exposures as risk factors for malignant lymphomas

BACKGROUND

Malignant lymphomas (Hodgkin disease [HD] and non-Hodgkin lymphoma [NHL]) have been subject to several epidemiologic studies and found to be associated with various environmental exposures, especially solvents, wood, and phenoxy herbicides.

METHODS

Various determinants for HD and NHL were evaluated in a case-referent study encompassing 31 cases of HD, 93 cases of NHL, and 204 referents, all alive. Information on these determinants, mainly occupational exposures, was obtained by mailed questionnaires.

RESULTS

Crude odds ratios were increased for various occupational exposures, i.e., exposures to solvents, pesticides, metal fumes, welding, and fresh wood, and nursing. Further analyses based on logistic regression indicated exposure to phenoxy herbicides and fresh wood among sawmill workers, lumberjacks, and paper pulp workers to be significant risk factors for HD. Welding, working as a lumberjack, nursing, and ex-smoking were associated with a significantly increased risk for NHL. Radiographic examinations were negatively associated with HD, as was office work for NHL.

CONCLUSIONS

The results were mainly in agreement with the findings of earlier studies, but diverging associations also appeared.

non-Hodgkin's lymphoma and occupation in Sweden: a registry based analysis

Incidence of non-Hodgkin's lymphoma in different employment categories was evaluated from the Swedish Cancer-Environment Registry, which links cancer incidence during 1961 to 1979 with occupational information from the 1960 census. New associations were found for men employed in shoemaking and shoe repair, porcelain and earthenware industries, education, and other white collar occupations. Several findings supported associations found in other countries, including excesses among woodworkers, furniture makers, electric power plant workers, farmers, dairy workers, lorry drivers, and other land transport workers. Risks were not increased among chemists, chemical or rubber manufacturing workers, or petrochemical refinery workers. Caution must be used in drawing causal inferences from these linked registry data because information on exposure and duration of employment is not available. Nevertheless, this study has suggested new clues to possible occupational determinants of non-Hodgkin's lymphoma.

Occupation and soft-tissue sarcoma in northeastern Italy

The influence of occupation and exposure to different agents on the risk of developing soft-tissue sarcoma (STS) was assessed in a case-control study based on 93 cases of STS (53 men and 40 women) and 721 controls (371 men and 350 women), conducted in northeastern Italy. No risk elevation was found in subjects employed in agriculture (odds ratio [OR] for greater than 10 years = 0.8, 95 percent confidence interval [CI] = 0.4-1.5), nor in those who reported exposure to pesticides or herbicides (OR = 0.4, CI = 0.1-1.2). Similarly, neither occupation in the furniture, upholstery, and mechanics industries, nor exposure to livestock or meat processing, wood dust, metal dust, and dyes or paints were associated with STS risk. Workers who reported exposure to chemical agents or to benzene or other solvents for more than 10 years had, respectively, a 1.8-fold (CI = 0.7-4.4) and a 2.2-fold (CI = 0.9-5.5) higher risk of developing STS. Although the small number of STS cases limits the interpretation of the study results, these findings weigh against the hypothesis that pesticides, herbicides, or other exposures related to agriculture, play an important role in the etiology of STS. The direct associations with exposure to chemical agents and benzene or other solvents, albiet not statistically significant, may provide a useful hint for future investigations.

Occupation and risk of Hodgkin's disease in north-east Italy

The relationship between occupation and exposure to several occupational agents and Hodgkin's disease (HD) was investigated in a case-control study of 152 cases and 613 controls with acute diseases admitted to all hospitals in Pordenone province, north-east Italy. Among cases, there was a significant excess of individuals occupied in agriculture (odds ratio, OR for greater than 10 years = 2.2, 95% confidence interval, CI:1.3-3.7), who were exposed to livestock and meat processing (OR = 3.4, 95% CI:1.7-6.6), herbicides and pesticides (OR = 3.2, 95% CI:1.6-6.5). When the relationship between agriculture and specific exposures was assessed, it appeared that contact with some still unidentified animal-related agent involved in livestock farming and meat processing may be at least as important in determining HD risk as exposure to herbicides and pesticides and, probably, more important than occupation in agriculture per se.

Epidemiologic studies of cancer in agricultural workers

The incidence of cancer in agricultural workers is generally low, in part due to the low prevalence of cigarette smoking in this group. However, agricultural workers have elevated risks for several specific cancer types including leukemia, Hodgkin's disease, non-Hodgkin's lymphoma, multiple myeloma, and cancers of the lip, stomach, prostate, brain, and connective tissue. Two major groups of risk factors have been proposed as causes of hematologic malignancies in agricultural workers. The first group includes various agricultural chemicals. In particular, several studies have found increased risks of malignant lymphoma and soft tissue sarcoma in persons exposed to phenoxy herbicides. However, the evidence is inconsistent and there is a wide variation in relative risk estimates. The second group of risk factors includes various animal viruses. There is currently little evidence concerning the zoonotic nature or human carcinogenicity of these viruses. However, leads have been suggested by recent evidence of increased risks of hematologic malignancies in abattoir workers, veterinarians, and meat inspectors. A third hypothesis, for which little evidence is currently available, is that agricultural work may involve prolonged antigenic stimulus leading to lymphoproliferation. The factors responsible for the increased risks for cancers other than hematologic malignancies are not well understood but may also involve exposure to chemicals or viruses.