Airways Disease and Occupational Exposure to Nonfibrogenic Dust

Abstract

The objective of this workshop was to address the question implicit in its title: Are particulates not otherwise classified (PNOC) a cause of airways disease? This, the first presentation in the workshop, was aimed at providing a framework within which to review the evidence and provide recommendations. A historical perspective was used to emphasize the shift in focus in occupational lung disease over this century. Thus the largely agent-specific lung parenchymal dust diseases (in particular, the pneumoconioses) were responsible for most of the lung disease mortality and morbidity attributable to occupational exposures in the first half of the century. By the later decades of the century their place had been ceded to disease of the airways, acute and chronic, part of a midcentury epidemic in which tobacco usage was a major environmental cause. Airways disease was broadly defined and included asthma, chronic bronchitis, emphysema, and chronic obstructive pulmonary disease. The workshop focused on the ill health consequences of exposure to PNOC while recognizing that in many, if not most, workplaces, exposures are complex and include, in addition to PNOC, fumes, vapors, and/or chemicals, as well as fibrogenic dusts. The workshop will have fulfilled its mandate if (1) the work-related burden of airways disease is assessed; (2) an estimate is made of its public health burden and whether it is sufficient to merit public health intervention; and if so, (3) a determination is made of the key gaps in knowledge that should be addressed to direct prevention. Gaps in knowledge considered key are likely to vary with the background and expertise of the participants, and the workshop should be in a position to synthesize their views, if not achieve some consensus on their relative importance. An additional goal of the workshop was to formulate research questions capable of being addressed in a practical way and in real time to address these gaps in knowledge.