Pulmonary dysfunction in silica-exposed workers: A relationship to radiographic signs of silicosis and emphysema
✍ Scribed by Xiaorong Wang; Eiji Yano
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 126 KB
- Volume
- 36
- Category
- Article
- ISSN
- 0271-3586
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✦ Synopsis
Background It has been established that occupational exposure to silica dust may cause signi®cant impairment of pulmonary function. To compare the contribution of silicosis and emphysema to pulmonary dysfunction, radiographic signs of silicosis and emphysema in silica exposed workers were analyzed. Methods Two hundred and twenty workers exposed to silica working in a Chinese refractory plant were selected as study subjects. Their ®ndings of silicosis and emphysematous changes on radiograph were classi®ed and evaluated. A questionnaire on respiratory symptoms, smoking, and occupational history was administered. All the workers performed measurements of spirometry and CO single-breath diffusing capacity. Results Radiographic hyperin¯ation was detected in 9% of the workers without silicosis and in 33% of the workers with silicosis. Silicosis was signi®cantly associated with hyperin¯ation after adjusting for exposure duration, age, and smoking. Respiratory symptoms were more frequent in the more severe cases of silicosis. Regression analysis showed that silicosis was signi®cantly associated with decreases in the parameters of pulmonary function, but the signi®cance disappeared when the hyperin¯ation term was added to the models. Radiographic hyperin¯ation was strongly associated with decreases in FEV 1 and FEV 1 /FVC while relevant factors were controlled. Comparison between workers with and without hyperin¯ation showed that the former had signi®cantly lower pulmonary function values. Conclusion The results suggest that emphysema associated with silicosis is likely to be responsible for pulmonary obstruction and decreased diffusing capacity occurring in silica-exposed workers. Am.