Death rates of miners and ex-miners with and without coalworkers' pneumoconiosis in South Wales

Abstract

At present the only practical method by which a diagnosis of coalworkers' pneumoconiosis can be made in life is by means of chest radiographs. Such a diagnosis, however, merely signifies the presence of radiological abnormalities due to exposure to coal dust. Of itself, it can tell us little about pulmonary disability or future loss of expectation of life. It is thus unfortunate that the radiograph has become practically of such importance, both in relation to dust suppression and to industrial compensation, before the necessary correlations have been established, i.e., between dust concentration , time of exposure, and rate of appearance of radiological abnormality on the one hand, and the radiological category of coalworkers' pneumo-coniosis, age, pulmonary disability, and loss of expectation of life on the other. Roach (1953) has shown that a relationship exists between dust concentration, time, and the appearance of the first radiological abnormalities. and Carpenter (1956) discuss the relationship between age, radiological category, and pulmonary disability. This paper attempts the third of these correlations-the relationship between age, radiological category, and expectation of life. The problermi has been much misunderstood in the past amongst both doctors and laymen. The radiological changes in coalworkers' pneumoconiosis are particularly striking, and some doctors who tend to judge these changes by comparing them with tuberculosis, with which they are better acquainted, have sometimes given too gloomy a prognosis. Moreover, people have an understandable difficulty in differentiating between figures relating to those suffering from coalworkers' pneumoconiosis who die and figures relating to those who die from pneumoconiosis. The publicity given to the former figures and the lack of information about the latter have probably given an exaggerated picture of the seriousness of the disease from the point of view of mortality. The literature on the effect of pneumoconiosis on mortality is somewhat limited. Fletcher (1948) pointed out that the standardized death rates of coal-miners in England and Wales for all respiratory diseases except tuberculosis, when compared with those rates for all occupied and retired males, showed a marked excess for the four periods He also pointed out that it was the coal-miners over the age of 55 in whom this excess of deaths was seen and suggested that this excess of deaths might be due to deaths from coalworkers' pneumoconiosis. The only detailed study of death rates associated with coalworkers' pneumoconiosis is that of Stewart, Davies, Dowsett, Morrell, and Pierce (1948). They followed …