The prevention of occupational asthma.

There is sufficient understanding of the causation of occupational asthma for preventive action to be appropriate. To date, attempts appear to have been largely unsuccessful and this appears to be largely due to nonscientific/technical obstacles. These include the fragmented nature of the disease, its low public and industrial profile, and its comparative rarity in single workplaces. Nonetheless the disease has high individual and societal costs. Prevention strategies should be concentrated on workplace-exposure controls, accompanied by intense educational and managerial improvements. Methods of secondary prevention appear to be successful but require considerable refinement. Screening (out) of potential new employees is inefficient and likely to remain so; and in any case is beset by difficult ethical and legal issues. There are only a handful of published studies reporting evaluations of preventive programmes. None is entirely rigorous but each suggests that primary and secondary prevention are both feasible and highly effective. The evaluation of preventive strategies is difficult, not only because of the low incidence of the disease in individual workplaces but also because of the failure of many epidemiologists to engage in this work. Considerably more cooperation between scientists in the field, regulatory authorities and industry is required.