VENTILATORY FUNCTION OF FACTORY-WORKERS EXPOSED TO TEA DUST

A cross-sectional study was conducted in order to determine the preval ence of respiratory symptoms and the effect on ventilatory capacity in workers exposed to tea dust for at least live years during the siftin g process of tea manufacture compared to a control group oi field work ers who were not exposed to tea dust previously. Fifty-three subjects each in the study and control groups were matched for age, sex, ethnic group and height. Prevalence oi chronic respiratory symptoms was obta ined by questionnaire. Spirometric measurements included forced vital capacity (NC), forced expiratory volume in the first second (FEV(1.0)) and forced mid-expiratory Row rate (FEF(25-75%)). The study group had a chest radiograph. The odds ratio for any chronic respiratory sympto m was 11.6 (95% confidence interval [CI] = 3.7-39.4) in the study grou p. Mean values for the spirometric tests were lower in the study group ; the differences in FEV(1.0) and FEF(25-75%) were significant. Tuberc ulosis was not found in the study group, while one subject (2.4%) had radiological evidence of bronchiectasis. It may therefore be concluded that chronic tea dust exposure causes increased prevalence of respira tory symptoms and a significant degree of small airways obstruction.