Monitoring of peak expiratory flow rates in cork workers' occupational asthma

Suberosis is an occupational lung disorder of cork industry workers usually presenting as an extrinsic allergic alveolitis, but airway involvement in some cases makes the diagnostic approach complex. We assessed peak expiratory flow rates (PEF) in 17 cork workers with asthma symptoms that worsened at work, comparing three methods of PEF graph analysis. Complete agreement (three observers) was found in 12 of 17 cases (70.6%) with the visual inspection of mean daily values and in 11 of 17 cases (64.7%) with the minimum, maximum, and mean daily values (without any consensus in two cases). According to the mean PEF graph, there were eight positive readings (47%), five negative readings (29%), and four dubious readings (24%); with the other graphic analysis, two of the dubious cases were reclassified as negative. When we analyzed daily variability >20%, we found only three positive results, one of which was in absolute disagreement with the visual analysis. Our results suggest that it is possible to demonstrate occupational asthma in cork work exposure. The visual inspection of PEF monitoring shows a greater number of positive results than the index of daily variability; however, the latter may help to sort out dubious cases.