Chronic Respiratory Symptoms and Ventilatory Function in Workers Exposed to Tea Dust: Effect of Duration of Exposure and Smoking

Many studies reviewed show that both workplace exposure to organic dust and smoking may cause chronic respiratory symptoms and airflow limitation in susceptible subjects. We performed a case-control study including 63 tea workers (36 male and 27 female, aged 36-55, duration of employment 3–30 years) and an equal number of office workers, matched by sex and age. Chronic respiratory symptoms (chronic cough, phlegm, dyspnea gr. 3-4, wheezing, wheezing with dyspnea, and chest tightness) were recorded by questionnaire. Skin prick tests and spirometric measurements were carried out. Environmental measurements were performed on site during the work shifts. Prevalence of chronic respiratory symptoms in exposed workers was insignificantly higher (44.8% vs. 33.6%). Significantly higher prevalence of individual chronic respiratory symptoms was found for phlegm (P<0.05) and dyspnea gr. 3-4 (P<0.05). Chronic respiratory symptoms in exposed workers were significantly associated with duration of exposure (P<0.05) and current smoking (P<0.05, P=0.011), whereas relation of chronic respiratory symptoms and current smoking in controls just missed the significance (P=0.056). Values of FVC, FEV1, FEV1/FVC% and small airways indices in exposed workers were significantly lower. Small airways changes in exposed workers were strongly linked to duration of exposure (P<0.05) and current smoking (P<0.01), whereas relation of small airways changes and current smoking in controls was not significant. Our data suggest interactive influence of workplace exposure to tea dust and current smoking in development of chronic respiratory symptoms and airflow limitation with predominantly smaller airways affecting.