Prospective study of airway obstruction in a population with small airway disease.

In this paper, we discuss results showing an increase of bronchial obstruction due to exposure in an iron foundry. The research has been conducted in two steps: in the first, we selected a sample of 100 subjects, all working in the iron foundry, who were affected only by small airway obstruction. In a second step, 30 months later, 99 of these subjects were re-examined and the present airway condition determined. In 43 subjects we found abnormal results of the tests indicating total airway obstruction after the 30 months. After properly accounting for ageing, we found that even in the subsample of non-smokers a deterioration had occurred, showing an effective contribution of environmental pollution. The use of RV, MMEF, CV, DLCO for detecting small airway obstruction is evaluated. The combination of RV, MMEF and CV is the most efficient mosaic of tests for the selection of subjects with small airway obstruction (89%) and with high probability of developing total airway obstruction (44%).