Occupational exposure and asthma control.

In this issue of the European Respiratory Journal, DUMAS et al. [1] describe associations between occupational disinfectant exposure and asthma control in US nurses. Asthma control was defined by using the Asthma Control Test (ACT) and based on responses to five questions on activity limitations, frequency of symptoms and frequency of use of quick-relief medication in the past 4 weeks (β-agonist inhaler, e.g. albuterol, for symptom control). This instrument is not commonly considered an end-point in studies on occupational exposures and asthma, while asthma control is of particular relevance for asthma patients at work. Thus, the use of asthma control using the ACT is of particular interest [2]. According to the Global Initiative for Asthma Statement, asthma control is the extent to which manifestations of asthma can be observed, or have been reduced or removed by treatment. Asthma control has two dimensions; treatment of symptoms and future risk of adverse outcomes. Variables that can determine future adverse outcomes are lung function, exposure to allergens and non-specific stimuli (smoking, indoor and outdoor air quality), socio-economic and psychological problems, comorbidities and eosinophilia. These variables also determine future outcomes of occupational asthma. The ACT includes a limited set of these, in particular variables associated with treatment of symptoms.