Subject(s)
Environmental Health , Environmental Pollution/adverse effects , Public Health , Chemical Industry/statistics & numerical data , Humans , Italy/epidemiology , Leukemia/chemically induced , Leukemia/epidemiology , Mesothelioma/chemically induced , Mesothelioma/epidemiology , Petroleum/adverse effects , Pleural Neoplasms/chemically induced , Pleural Neoplasms/epidemiology , Risk FactorsABSTRACT
BACKGROUND: Asbestos exposure has been definitively found to be associated with both mesothelioma and lung cancer. Nevertheless, in the overall population of oil refinery workers potentially exposed to asbestos, many studies clearly show a definitely increased risk of mesothelioma, but no proven excess of lung cancer after comparison to the general population. Through the presentation of new data and the re-appraisal of two recent and independent epidemiological studies conducted in Liguria, Italy, and Ontario, Canada, we attempt to shed light on this apparently paradoxical finding. METHODS: Lung cancer mortality was studied among maintenance workers exposed to asbestos, and among two other subgroups of refinery employees: blue collar and white collar workers. The comparison with blue collar workers was performed in order to take into account the role of healthy worker effect, smoking habit, and the socioeconomic level. The comparison with white collar workers was performed to control for other occupational lung carcinogens. RESULTS AND CONCLUSIONS: Results reveal a consistency between the two studies and show that 96-100% of the mesotheliomas and 42-49% of the lung tumors arising among maintenance workers were attributable to asbestos exposure. Our new analysis, estimating two cases of asbestos-related lung cancer for each case of mesothelioma, confirms published findings on the magnitude of asbestos-related tumors in oil refineries.
Subject(s)
Asbestos/adverse effects , Lung Neoplasms/chemically induced , Mesothelioma/chemically induced , Occupational Exposure , Petroleum/adverse effects , Data Interpretation, Statistical , Female , Humans , Italy/epidemiology , Lung Neoplasms/epidemiology , Male , Mesothelioma/epidemiology , Occupational Diseases/mortality , Pleural Neoplasms/chemically induced , Pleural Neoplasms/epidemiology , Smoking/adverse effectsABSTRACT
This retrospective study examines the mortality patterns of a relatively young cohort of 81,746 former and current petrochemical company employees. Standardized mortality ratios (SMR) for 1979 through 1992 are generally from about unity to well below unity for major causes and numerous specific causes of death studied by gender/race/job subgroups. Findings of note include a SMR (based on incidence rates) of 1.94 (95% confidence interval [CI], 1.04 to 3.33) for mesothelioma, and a SMR of 1.81 (95% CI, 0.90 to 3.24) for chronic lymphocytic leukemia, both among males hired before 1960. All male semiskilled operatives have a 1.6-fold increase (95% CI, 1.07 to 2.29) in motor vehicle accident deaths, with declining rates since the mid-1980s. The overall SMR for acquired immunodeficiency syndrome (AIDS) is at unity (69 deaths), with excesses in technician and office worker subgroups. Four decedents with lymphoma (code 202.8 in 9th revision ICD) had AIDS as a secondary cause of death, suggesting the need to examine secondary causes when studying lymphopoietic conditions. This routine surveillance activity provides leads regarding the presence or absence of excess mortality risk.
Subject(s)
Cause of Death , Chemical Industry , Occupational Diseases/mortality , Petroleum , Accidents, Occupational/mortality , Acquired Immunodeficiency Syndrome/mortality , Adult , Cohort Studies , Female , Follow-Up Studies , Humans , Leukemia, Lymphocytic, Chronic, B-Cell/chemically induced , Leukemia, Lymphocytic, Chronic, B-Cell/mortality , Male , Mesothelioma/chemically induced , Mesothelioma/mortality , Middle Aged , Occupational Diseases/chemically induced , Petroleum/adverse effects , Pleural Neoplasms/chemically induced , Pleural Neoplasms/mortality , Retrospective Studies , Survival Analysis , United States/epidemiologyABSTRACT
Ascorbic acid administered with drinking water, in a concentration of 2.5%, together with sucrose (1%) was found to significantly inhibit the development of mesothelial and pleural tumors induced in Wistar rats by asbestos treatment. Said agents, however, failed to influence spontaneous carcinogenesis.
Subject(s)
Ascorbic Acid/therapeutic use , Pleural Neoplasms/prevention & control , Administration, Oral , Animals , Asbestos , Ascorbic Acid/administration & dosage , Female , Male , Mammary Neoplasms, Animal/prevention & control , Neoplasms, Mesothelial/prevention & control , Pleural Neoplasms/chemically induced , Rats , Rats, Wistar , WaterABSTRACT
Pathological effects of asbestos are probably dependent on the size and surface properties of the fibers. Surface-modified chrysotile fibers were injected into the pleural cavity of rats to investigate the potency of the fiber to induce mesothelioma. Chrysotile fibers were modified by a phosphorylation process, resulting in the presence of phosphorus at the fiber surface. Phosphorylated samples were characterized by enhanced durability and reduced affinity for biological macromolecules. Five samples were tested: 1 untreated and 4 phosphorylated. ChrP1, ChrP2 and ChrP3 corresponded to phosphorylated samples obtained by first, second and third passages through an Alpine classifier; Pm was defibrillated ChrP1. The number of fibers per microgram and the size distribution were determined by transmission electron microscopy and classified in 4 size groups. Groups of 35 rats were inoculated with 20 mg of fibers suspended in 0.9% NaCl solution. No mesothelioma was found in the saline controls. All fiber samples were proficient in producing mesothelioma; the percentages were different between groups and untreated chrysotile but not significantly so. The differences may be explained on the basis of the number of fibers injected which were greater than 8 microns in length and less than 0.25 microns in diameter. The findings of a proficiency of long fibers to produce mesothelioma, previously reported by others for glass fibers, could be applied to chrysotile.
Subject(s)
Asbestos/toxicity , Carcinogens/toxicity , Mesothelioma/chemically induced , Phosphorus/toxicity , Pleural Neoplasms/chemically induced , Animals , Asbestos, Serpentine , Male , Mesothelioma/pathology , Phosphorylation , Pleural Neoplasms/pathology , Rats , Rats, Inbred StrainsABSTRACT
Groups of rats, 24 male and 24 female, approximately 8 weeks old, were dosed by a single intrapleural injection with a saline suspension of refractory alumina fibres (Saffil fibres ICI plc) either as manufactured or after extensive thermal ageing; or one of two aluminosilicate ('ceramic') fibres with different diameter distributions. Similar groups were dosed with a suspension of UICC chrysotile A asbestos or saline solution to serve as positive and negative controls respectively. Rats were maintained to 85% mortality and all decedents and terminal sacrifices were closely examined for the presence of mesothelioma. Malignant mesothelioma was diagnosed in ten rats, seven dosed with asbestos and three dosed with aluminosilicate fibre B. No mesothelioma was detected in any rat dosed with Saffil fibres or aluminosilicate fibre A or in negative controls. The results support the predicted inert nature of Saffil alumina fibres and provide further evidence for the importance of fibre dimension in the induction of mesothelioma. The implication of the results for inhalation exposures is discussed.
Subject(s)
Aluminum Oxide/toxicity , Aluminum Silicates/toxicity , Pleural Neoplasms/chemically induced , Animals , Asbestos/toxicity , Female , Hot Temperature , Male , Mesothelioma/chemically induced , Peritoneal Neoplasms/chemically induced , Pleural Neoplasms/etiology , Rats , Rats, Inbred StrainsABSTRACT
Sodium selenite given in drinking water in a 4 ppm solution during the whole experiment was found to significantly inhibit pleural carcinogenesis induced in Wistar rats by intrapleural injection of chrysotile-asbestos powder (20 mg three times, monthly, in 0.5 ml of physiologic saline). Mesothelioma of the pleura was induced in 20.5%. However, chrysotile alone induced tumor in 43.8%. Sodium selenite failed to influence carcinogenesis in other sites. Possible mechanisms of sodium selenite action are discussed.
Subject(s)
Asbestos, Serpentine/toxicity , Pleural Neoplasms/chemically induced , Pleural Neoplasms/prevention & control , Sodium Selenite/administration & dosage , Animals , Asbestos, Serpentine/administration & dosage , Chi-Square Distribution , Drug Evaluation, Preclinical , Dust/adverse effects , Female , Male , Pleural Neoplasms/mortality , Rats , Rats, WistarABSTRACT
This review presents background information and literature documentation to supplement the "Recommended Procedures for Sampling and Counting Asbestos Fibers: Procedures for the Evaluation of Occupational Exposure to Airborne Asbestos" prepared by the joint ACGIH-AIHA Aerosol Hazards Evaluation Committee. It reviews the nature of the inhalation hazard associated with asbesots fibers, the sampling and analytic methods which have been used, and a rationale for the selection of the membrane filter sampling-optical phase microscope identification and assay methodology which is recommended.