Pathological aspects of asbestosis.

WIDESPREAD recognition of asbestosis dates from the work of Merewether and Price in 1930. They investigated 363 asbestos workers and concluded that there was a pneumoconiosis resulting from asbestos inhalation, that this condition shortened life, and that measures to diminish the atmospheric concentration of asbestos dust would reduce the incidence of the disease. In 1931 asbestosis was accepted as a compensatable disease in Great Britain and steps were taken to reduce the risk in the asbestos industry. 18 years later Wyers (1949) found that the age at death in this disorder had increased and that finger-clubbing had become more common. He suggested that these changes were due to a more chronic form of the disease resulting from improved dust control in the industry following the legislation of 1931. Currently however, the number of new cases of asbestosis in Great Britain is increasing, their frequency suggesting an incidence rate of at least five per thousand of those occupationally exposed (McVittie, 1965). Though earlier reports indicated that tuberculosis was common in asbestosis (Wyers, 1949; Gloyne, 1951; Bonser, Foulds and Stewart, 1955) it appears to be a rare complication at the present time (Buchanan, 1965). Within the past few years it has become increasingly apparent that exposure to asbestos is associated with a further hazard. This is the development of malignant disease in the lung and serosal membranes and possibly the gastrointestinal tract. These neoplastic complications have given rise to much concern in view of the widespread use of asbestos in industry, its almost ubiquitous distribution in the modern urban community and the fact that current information does not permit the definition of safe levels of exposure. Pathological studies have made an important contribution to knowledge of the effects of asbestos exposure and are reviewed in this paper.