THE MINERAL DUST DISEASES

The mineral dust diseases, also called the pneumoconioses, comprise a wide spectrum of conditions ranging from diseases characterized by diffuse collagenous pulmonary reactions to relatively small lung burdens of bioactive dusts (e.g. silicosis, asbestosis) to diseases characterized by largely non-collagenous reactions in the face of heavy lung dust burdens (e.g. coal workers pneumoconiosis). According to information submitted to the International Labour Office, which is however incomplete, substantial numbers of individuals are still at risk for the mineral dust diseases in the workplaces of the world. An overview of their epidemiology in industrialized and industrializing countries reveals more commonalities than contrasts. Commonalities include the major determinants of disease (including exposure level, intensity and particle size distribution), their clinical manifestations and, probably, secular trends towards less clinically severe disease, at least in the larger, better controlled workplaces. Still a risk however, in both industrializing as well as industrialized countries, are the small, uncontrolled workplaces, often the source of mini-epidemics. Contrasts relate to the incidence and/or prevalence rates of tuberculosis amongst workforces at risk for the mineral dust diseases. Rates, which are invariably higher in industrializing than in industrialized economies, usually reflect the background tuberculosis rates in the populations which furnish the industrial workforces and they should be the target for control measures. Research in the industrialized countries should focus on disease mechanisms and on the bioactivity of workplace contaminants, old and new, and in the industrializing countries on the distribution and determinants of mineral dust diseases in their workplaces. All information gathered, whether by governments, unions or industry should be in the public domain, to maximize the potential benefit to be derived from exchanging experiences.