Mesotelioma pleural y exposición ambiental al amianto
Asbestos is a generic term applied to a group of fibrous silicates. There are three commercially important forms: chrysotile, crocidolite, and amosite. All of them are carcinogenic, capable of causing mesothelioma and lung cancer. Malignant mesothelioma is a rare tumour mainly located in the pleura. Most mesotheliomas are fatal within 12-24 months of diagnosis, and have a latency period of 20-50 years. There is strong evidence supporting the causal association between mesothelioma and occupational exposure to asbestos. Nevertheless, with the virtual cessation of high-dose occupational exposure to asbestos, public health attention has turned to the risks of exposure at lower doses arising from non-occupational sources. Domestic exposure results from asbestos fibres brought home by workers exposed in the workplace. Environmental exposure may result from residence in the vicinity of a single well-identified source of asbestos pollution. However, further studies are needed to investigate whether the industrial and domestic use of asbestos may produce sufficient environmental pollution to cause mesothelioma.
A population-based case control study was carried out in six areas from Italy, Spain and Switzerland, including 215 new histologically confirmed cases of pleural mesothelioma and 448 controls. A panel of industrial hygienists assessed the probability and intensity of asbestos exposure separately for occupational, domestic and environmental sources. Each occupational period was classified based on the information collected in the occupational history. Classification of domestic and environmental exposure of each residence was based on the presence and use of asbestos at home, asbestos industrial activities in the surrounding area and their distance from the dwelling.
Among 53 cases and 232 controls without evidence of occupational exposure to asbestos, handling asbestos material or presence of asbestos material at home susceptible to damage, as well as living within 2000 m of asbestos industries was associated with increased risk of mesothelioma. Typically these circumstances entail exposure to concentrations ranging from 0.1 to 5 f/l, about 1000 times lower than those measured in occupational settings. Among the 132 cases and 257 controls in the Spanish centres the main occupations with increased risk of mesothelioma were manufacture of asbestos cement, launderers, cleaners and pressers, electrical fitters, plumbers, and drivers of material-handling and related equipment. Almost 88% of mesotheliomas were attributable to asbestos exposure, 62% due to occupation and 26% from non-occupational origin.
Utilisation of asbestos has almost completely ended in most developed countries as the result of government bans. Nevertheless, asbestos manufacture continues in parts of the developing world. Even countries that have banned the material still have to devise strategies to cope with the asbestos that remains in place, monitoring potential effects of fibres used as asbestos substitutes, and surveillance of former asbestos workers and exposed populations in order to provide them with access to compensation.
Advisor:González, Carlos A.; Moreno, Víctor
School:Universitat Autónoma de Barcelona
Source Type:Master's Thesis
Keywords:418 departament de pediatria obstetricia i ginecologia
Date of Publication:12/01/2003