Glass bottle workers exposed to low-dose irritant fumes cough but do not wheeze

Workers exposed to irritant fumes experience symptoms both during the acute episode and afterwards. High-dose irritant exposure can result in permanent asthma, but the effects of chronic low-dose irritant exposure are not known. Glass bottle workers are exposed to irritant fumes, and have previously been reported to have an excess of symptoms. We designed a study to compare irritant-exposed glass bottle workers with hospital workers matched for socioeconomic group, area of residence, age, sex, smoking habit, and allergic history. Symptoms reported, spirometry, flow cytometric indices of lymphocyte activation, and past medical and employment histories were compared. We also investigated the prevalence of bronchial hyperresponsiveness to inhaled methacholine and the cough response after inhalation of citric acid and capsaicin. Glass bottle workers showed an excess of upper respiratory tract symptoms, cough, and shortness of breath compared with matched hospital control workers. There was a significant excess of cough induced by citric acid and capsaicin in the bottle workers. However, wheeze, baseline spirometry, flow cytometry, and methacholine challenge were not significantly different between the two groups. These findings suggest that chronic irritant exposure produces an excess of symptoms and increased cough sensitivity but not asthma.