The Relative Importance of Clinical, Radiological and Pulmonary Function Variables in Evaluating Asbestosis and Chronic Obstructive Airway Disease in Asbestos Workers

Abstract

I. The relative power of sixteen clinical, radiological and pulmonary function variables for evaluating asbestosis and chronic osbtructive airway disease has been assessed by principal component analysis of the data from a survey of 201 asbestos workers.2. A decrease in the transfer factor (diffusing capacity) for carbon monoxide followed by a decrease in the vital capacity had the greatest power to measure the severity of both types of disease but had little ability to distinguish between the two.3. In decreasing order of potency, the best indicators for distinguishing between asbestosis and obstructive airway disease were forced expiratory volume as a proportion of vital capacity, phlegm, radiological pleural thickening, cough and finger clubbing. Low values in FEV/VC and high values in phlegm and cough indicated obstructive airway disease: high values of pleural thickening and finger clubbing indicated asbestosis in the present context. 4. The analysis also provided numerical scores for each individual that could be plotted on a two-dimensional diagram. Orientation along one axis showed the degree of involvement of individuals by lung disease, whereas separation along the other axis depended on the nature of the disease process, asbestosis and obstructive airway disease in this instance.Although advanced asbestosis is readily recognized, there is wide disagreement about the order of appearance and relative importance of the initial manifestations.

Railroad workers with pleural plaques: I. Spirometric and nitrogen washout investigation on smoking and nonsmoking asbestos‐exposed workers

“…Our results show that VC is the most sensitive indicator for asbestos-induced lung function change. This is in accordance with earlier observations [Regan et al, 1971;Fournier-Massey and Becklake, 1975;Jarvholm and SandCn, 19861. We could not demonstrate any influence of smoking on VC, which suggests that smoking does not increase the tendency for lung restriction in subjects with asbestos-induced pleural plaques without radiographic pulmonary fibrosis.…”

Radiographic and physiological findings in patients with asbestosis.

“…The abnormalities of pulmonary function in patients with asbestosis have already been described well (17,21). Bader et al (1) concluded that the most sensitive index of progression of the disease is the change in vital capacity, which correlates well with radiographic changes.…”

“…Opinions differ, however, concerning the value of the gas transfer factor in the diagnosis of asbestosis (14,22). The correlations between the radiographic findings and lung function of asbestos workers have varied (1,2,14,17,21,22). Asbestosis is regarded as a difficult disease to diagnose.…”

Pulmonary Asbestosis — An Example of Industrial Diffuse Lung Disease

“…31, 34 Inter-observer variation is high unless the hyponychial angle is There also appears to be some interaction with cigarette ~moking. '~…”