The principles of predicting the individual risk of silicosis and silicotuberculosis.

A series of investigations conducted in different "silicosis-risk" industries using a methodology based on the mathematical theory of pattern recognition has shown that in the given conditions of dust exposure, the probability of contracting pneumoconiosis depends for each individual on a complex influence of many factors, both environmental and intrinsic for the individual. Genetic predisposition was one of the most important factors and while the direction in which a factor influences predisposition was the same in every industry, its relative contribution to predisposition to simple silicosis was different in the studied working populations. So a reliable prediction of the high probability of this form of pneumoconiosis on the basis of such a multifactorial analysis is possible only with respect to specific conditions of a particular industry. The complex of factors determining predisposition to silicotuberculosis is more general: this complex comprises both factors influencing susceptibility to silica dust and specially those influencing susceptibility to tuberculosis. Despite the low prevalence of genetic resistance to pneumoconiosis in working populations, the risk of contracting the disease in modern industrial conditions of relatively low dust exposure is high only for a proportion of workers for whom the genotype of predisposition to silicosis or to silicotuberculosis coincides with a most unfavourable combination of non-genetic factors enhancing this predisposition. In the opinion of the authors, the task of screening off those applicants for a "silicosis-risk" employment for whom the risk may be estimated as high on the basis of the developed methodology, is quite feasible.