[Increase of nonspecific bronchial reactivity after occupational exposure to vanadium]

A study was conducted to evaluate the level of bronchial responsiveness among workers recently exposed to vanadium pentoxide during periodical removal of ashes and clinker from the boilers of an oil-fired power station. A total of 11 male workers were examined 40-60 hours after the last exposure; male subjects, comparable as to age and smoking habits and not exposed to vanadium, were randomly chosen among the employees of the same power station as a control group. None of the subjects in the two groups had symptoms of bronchial inflammation or significant airways obstruction. However, bronchial responsiveness, investigated using a methacholine challenge test, was significantly higher in the exposed group. It is suggested that exposure to vanadium increases bronchial responsiveness even without clinical appearance of bronchial symptoms. The role of such increased level of airways responsiveness as a risk factor for chronic obstructive lung disease is speculated.