Asbestos-related diseases of the lungs and pleura: uses, trends and management over the last century.

Asbestos is a descriptive term for a group of naturally occurring minerals known to mankind since ancient times. The main types of asbestos (chrysotile, and the amphiboles crocidolite and amosite) differ in chemical structure, biopersistence in human tissue and toxicity. Commercial exploitation, with little thought for environmental controls, increased over the twentieth century, particularly after World War II, to accommodate globalisation and the demands of the world's burgeoning cities. As its ill-health effects, both non-malignant (fibrosis of the lungs or asbestosis; pleural effusion, plaques and thickening) and malignant (mesothelioma, lung and other cancers), became evident, public pressure rose to control its use. The last decades of the last century saw decreases in exposure and rates of asbestosis in industrialised and in some less-industrialised countries, where pleural plaques and malignant mesothelioma are currently the most frequent manifestations of asbestos exposure. Longer follow-up of asbestos-exposed cohorts in mining and manufacturing has also strengthened the evidence of a fibre gradient in toxicity, with chrysotile exhibiting lower toxicity than the amphiboles, and amosite lower toxicity than crocidolite. The last decades of the twentieth century saw stabilisation and/or declines in mesothelioma rates in several industrialised countries. In less-industrialised countries, data on disease are sparse, exposure generally high and rates may peak in the future. Management of asbestos-related disease in the workplace requires collaboration between workers and unions (responsible for monitoring workplace dust levels, to which they must have access) and companies (responsible for engineering controls), reinforced by appropriate government regulations and by community support.