LONGITUDINAL DECLINE IN LUNG-FUNCTION IN PATIENTS WITH OCCUPATIONAL ASTHMA DUE TO WESTERN RED CEDAR

Background - There are few reports about longitudinal changes in lung function in asthmatic patients. Patients with asthma had a greater los s of lung function than normal healthy adults. To date, there have bee n no studies about the longitudinal changes in lung function in patien ts with occupational asthma. Methods - 280 male patients with red ceda r asthma (RCA) who were followed up for at least one year were the stu dy group. The exposed controls consisted of 399 male sawmill workers. Forced expiratory volume in one second (FEV(1)) was measured with a Co llins water spirometer. Changes in FEV, over time (FEV(1) slope) were calculated by a two point method for each subject. Atopy was considere d to be present if the subjects showed at least one positive response to three allergens by skin prick test. Results - Multiple regression a nalysis was carried out to examine factors that might affect longitudi nal decline in FEV(1). Patients with RCA who were still exposed had a greater decline in FEV(1) slope (-26 ml/y) than sawmill workers. Smoke rs also showed a greater rate of decline in FEV(1) (-43 ml/y) than non -smokers. Conclusions - Patients with RCA who continued to be exposed had a greater rate of decline in FEV(1) than sawmill workers. Early di agnosis of occupational asthma and removal of these patients from a sp ecific sensitiser is important in the prevention of further deteriorat ion of lung function and respiratory symptoms.