The continuing challenge to reduce the burden of occupational asthma.

W ith the reduction in the disease burden from the pneumoconioses in recent years, especially in developed countries, occupational asthma has emerged as the occupational lung disease of greatest importance. It is usually the most common respiratory condition reported in occupational disease surveillance programmes and makes a substantial contribution to the burden of asthma in the community, with an estimated population attributable risk of 15% and estimated annual cost to the USA of $US1.6 billion. Therefore, the introduction of prevention strategies to reduce the impact of occupational asthma, should be strongly supported. The editorial by Snashall in this issue describes the latest proposal by the Health and Safety Commission (HSC) to reduce the incidence of occupational asthma in the United Kingdom. This article acknowledges the limited success of past HSC prevention programmes. The proposed Strategy has five components corresponding to the key programmes in Securing health together, the HSC’s 10 year occupational health strategy, released in 2000. These components include the introduction of an Approved Code of Practice (ACoP), more targeted enforcement, better management systems, improved education, and more research. The primary stated aim of the new strategy is to reduce the incidence of occupational asthma, but in fact many of the proposed actions are appropriately aimed at other aspects of disease burden reduction, such as early detection and more effective case management, not just measures to reduce incidence. Snashall’s article indicates that the Strategy will also include action on asthma made worse by work; an inclusion made after a public consultation phase. While this is undoubtedly a worthwhile aim in terms of good occupational health practice, it is debatable whether it should be part of this particular Strategy. The aggravation of pre-existing asthma is usually due to non-specific triggers, rather than asthmagenic agents, so preventive measures will need to be different from those used to control asthmagens and will apply to a greater number of workplaces. Also, unlike occupational asthma, we have no surveillance data for aggravated asthma, which will make it difficult to monitor the success of the Strategy in the prevention of this problem. Finally, including action on asthma aggravation in the Strategy may dilute the prevention effort which can be directed towards reducing the impact of true occupational asthma. The target set for occupational asthma reduction in the Strategy is 30%, which is considerably higher than the HSC’s overall 20% reduction target for occupational disease by 2010. While this higher target is a laudable aim, it will require considerably more resources than those required to achieve a 20% reduction. A major problems with such targets is that the surveillance data on which they rely can take many years to show the effectiveness of prevention measures. As the usual period between exposure and disease for occupational asthma is quite short, this should be less of a problem for occupational asthma than for many other occupational diseases of longer latency. One note of caution relates to the proposal in the Strategy to extend and improve SWORD. It will be important to ensure that such changes do not, in themselves, lead to changes in the incidence data over time, for example by changes in case ascertainment, definitions, or reporting processes. Any future trends in the SWORD data should reflect real changes in the occurrence of occupational asthma in UK workplaces. Other measures will need to be developed to evaluate improvements in early detection and management of cases.