Contribution of host factors and workplace exposure to the outcome of occupational asthma.

The outcome of occupational asthma after diagnosis is often poor. The identification of factors associated with a worse outcome may help in the management of the disease, determining its prognosis and assessing the permanent impairment attributable to occupational exposure. The aim of this systematic review was to provide the available evidence from the medical literature to answer the question: "What is the contribution of host factors and workplace exposure to the risk of a bad outcome of occupational asthma?" A systematic literature search was conducted in March 2010. We retrieved 177 abstracts. Of these, 67 were assessed as potentially relevant. After full text evaluation, 35 articles that were actually relevant for the question were included in the analysis. The information obtained was sufficient to establish that older age, high-molecular-weight agents, impaired lung function and longer duration of exposure to the offending agent at the time of diagnosis had a negative role on the outcome of occupational asthma. Atopy and smoking at diagnosis did not seem to influence the outcome of occupational asthma. A limited number of studies considered sex and the pattern of asthmatic reaction on specific inhalation challenge and their findings were contradictory.