Exposure to Solvents and Risk of Non-Hodgkin Lymphoma: Clues on Putative Mechanisms

Abstract Malignant lymphomas are a group of diseases of uncertain etiology. Both environmental factors and genetic susceptibility have been reported as risk factors. We have conducted a population-based case-control study in Italy: all newly diagnosed cases of malignant lymphoma, in males and females ages 20 to 74 years in the 1991 to 1993 period, were identified; the control group was comprised of a random sample of the general population resident in each of the areas under study, stratified by sex and 5-year age groups. Overall, 1,428 non–Hodgkin lymphoma (NHL) cases and 1,530 controls were interviewed. Experts from each geographic area examined questionnaire data and assigned a level of probability and intensity of exposure to a range of chemical groups and individual chemicals. For those in the medium/high level of exposure, there was an increased risk of NHL for exposure to benzene, xylene, and toluene. We have examined the hypothesis that the effect of solvents is related to their immunotoxicity by analyzing the interaction with a previous history of autoimmune disease. We have found an apparent, though not statistically significant, increased risk of NHL in those with both exposure to benzene and a history of autoimmune disease (odds ratio, 16.3; 95% confidence interval, 0.8-321). In addition, an odds ratio of 29.8 (95% confidence interval, 1.4-650.2, based on nine exposed cases) was associated with high-level exposure to benzene in those with a positive family history of malignant hematologic neoplasms. Both hypotheses (i.e., the interaction with autoimmune diseases and with familial predisposition) indirectly suggest that an immunologic mechanism could be involved in lymphomagenesis from solvents. (Cancer Epidemiol Biomarkers Prev 2007;16(3):381–4

Immunotoxic effects of chemicals: A matrix for occupational and environmental epidemiological studies.

BACKGROUND: Many biological and chemical agents have the capacity to alter the way the immune system functions in human and animals. This study evaluates the immunotoxicity of 20 substances used widely in work environments. METHODS: A systematic literature search on the immunotoxicity of 20 chemicals was performed. The first step was to review literature on immunotoxicity testing and testing schemes adopted for establishing immunotoxicity in humans. The second step consisted of providing a documentation on immunotoxicity of substances that are widely used in work environment, by building tables for each chemical of interest (benzene, trichloroethylene, PAHs, crystalline silica, diesel exhausts, welding fumes, asbestos, styrene, formaldehyde, toluene, vinyl chloride monomer, tetrachloroethylene, chlorophenols, 1,3-butadiene, mineral oils, P-dichlorobenzene, dichloromethane, xylene, 1,1,1-trichloroethane, ethylene oxide). The third step was the classification of substances; an index (strong, intermediate, weak, nil) was assigned on the basis of the evidence of toxicity and type of immunotoxic effects (immunosuppression, autoimmunity, hypersensitivity) on the basis of the immune responses. Finally substances were assigned a score of immunotoxic power. RESULTS: Tables have been produced that include information for the 20 substances of interest, based on 227 animal studies and 94 human studies. Each substance was assigned an index of immunotoxic evidence, a score of immunotoxic power and type of immunotoxic effect. CONCLUSIONS: This matrix can represent a tool to identify chemicals with similar properties concerning the toxicity for the immune system, and to interpret epidemiological studies on immune-related diseases

Epidemiology, Public Health, and the Rhetoric of False Positives

BACKGROUND: As an observational science, epidemiology is regarded by some researchers as inherently flawed and open to false results. In a recent paper, Boffetta et al. [Boffetta P, McLaughlin JK, LaVecchia C, Tarone RE, Lipworth L, Blot WJ. False-positive results in cancer epidemiology: a plea for epistemological modesty. J Natl Cancer Inst 100:988-995 (2008)] argued that "epidemiology is particularly prone to the generation of false-positive results." They also said "the tendency to emphasize and over-interpret what appear to be new findings is commonplace, perhaps in part because of a belief that the findings provide information that may ultimately improve public health" and that "this tendency to hype new findings increases the likelihood of downplaying inconsistencies within the data or any lack of concordance with other sources of evidence." The authors supported these serious charges against epidemiology and epidemiologists with few examples. Although we acknowledge that false positives do occur, we view the position of Boffetta and colleagues on false positives as unbalanced and potentially harmful to public health. OBJECTIVE: We aim to provide a more balanced evaluation of epidemiology and its contribution to public health discourse. DISCUSSION: Boffetta and colleagues ignore the fact that false negatives may arise from the very processes that they tout as generating false-positive results. We further disagree with their proposition that false-positive results from a single study will lead to faulty decision making in matters of public health importance. In practice, such public health evaluations are based on all the data available from all relevant disciplines and never to our knowledge on a single study. CONCLUSIONS: The lack of balance by Boffetta and colleagues in their evaluation of the impact of false-positive findings on epidemiology, the charge that "methodological vigilance is often absent" in epidemiologists' interpretation of their own results, and the false characterization of how epidemiologic findings are used in societal decision making all undermine a major source of information regarding disease risks. We reaffirm the importance of epidemiologic evidence as a critical component of the foundation of public health protection

Leukaemia incidence among workers in the shoe and boot manufacturing industry: a case-control study

BACKGROUND: Previous reports have indicated an excess of leukaemia in Broome County, New York, particularly in the Town of Union. Surveillance of cancer incidence data indicates that a large proportion of these cases occurred among males ages 65 and older. Shoe and boot manufacturing has been the largest single industry in this area throughout much of the past century. Occupational studies from Europe suggest a link between leukaemia and employment in the shoe and boot manufacturing industry. However, researchers have not found a positive association between leukaemia and employment in the shoe industry among workers in the United States. METHODS: A matched case-control study was conducted to investigate the association between leukaemia incidence among males 65 and older and employment in the shoe and boot manufacturing industry. Thirty-six cases of leukaemia occurring between 1981–1990; among males age 65 and older; residing in the town of Union met the study case criteria. Death certificates were obtained for each of the cases. These were matched to death certificates of 144 controls on date of death and date of birth +/- 1 year. Death certificates were then examined to determine the employer and occupation of each study subject. Conditional logistic regression was used to determine the risk of leukaemia among those working in the industry. RESULTS: The risk of both leukaemia (OR = 1.47; 95% CI 0.70, 3.09) and acute myeloid leukaemia (OR = 1.19; 95% CI 0.33, 4.28) were elevated among those employed in the shoe and boot manufacturing industry, however neither was statistically significant. CONCLUSION: The results, though suggestive of an association between leukaemia and employment in the shoe and boot manufacturing industry, were not statistically conclusive due mainly to limited study power. Several additional limitations may also have prevented the observance of more conclusive findings. Better exposure assessment, information on length of exposure and types of job held, control of confounding factors and information on chemicals used by this company would strengthen any future investigation

Prato: The Social Construction of an Industrial City Facing Processes of Cultural Hybridization

This chapter deals with a widely studied case, that is, Prato, a middle-sized city with rooted industrial traditions, in the Centre of Italy. Prato is a textile industrial district embedded in the so-called Third Italy—an area characterized by the presence of small firms spread throughout the territory, linked together in supply and subcontracting relationships—which, in the last twenty years, has undergone a profound transformation as a consequence of the crisis of textile and immigration, leading to the formation of a large Chinese community. The related changes brought with them problems of social cohesion and sustainable development. The authors address these issues by analyzing both academic and public discourses on Prato. Their basic idea is that common stereotypes act as drivers of a public discourse that prevents the city to re-negotiate its identity. The analysis concludes that different forms of hybridization—particularly cultural hybridization—are occurring, which would need further investigations