Reference

BOHRF Original Authors' Main Conclusions

The original authors' main conclusions are taken from Abstract, Results and Discussion. They are decided upon by the authors of the BOHRF occupational asthma guidelines and form part of the guidelines.

Subjects with Toluene di-isocyanate (TDI) -induced asthma were studied over an average follow-up period of 48 months. At least 1 year after diagnosis, a specific bronchial responsiveness test with TDI was repeated. A significant positive correlation between months of follow-up and provocative dose inducing a 20 percent fall in FEV1 (PD20FEV1) methacholine was observed in 5/16 subjects. In most subjects, non-specific bronchial hyper-responsiveness did not change. 9/16 became non-responsive to TDI at follow-up examination, but only 3 of these showed a significant increase in PD20FEV1 methacholine. 7/16 were still responsive to TDI. Study confirms long-term persistence of asthmatic symptoms and which non-specific bronchial hyper-responsiveness in asthma due to TDI after cessation of occupational exposure. Recovery from TDI-induced asthma can occur and only after long-term work cessation. Non-specific bronchial hyper-responsiveness to methacholine can persist even in absence of bronchial hyper-responsiveness to TDI, suggesting permanent chronic damage to mechanisms controlling airway tone.

BOHRF Associated Evidence Statements

The BOHRF occupational asthma guidelines state that this reference is associated with the following evidence statements