Case control study on pulmonary dysfunction caused by silicosis

169 male silicosis patients were selected as case group and 96 healthy male miners exposed to silica dust were selected as the controls.All the subjects were invited to perform a questionnaire and lung function examination at the same time.The pulmonary dysfunction was classified according to the ratios of tested and predicted values.Results showed that all parameters of lung function declined significantly in case group compared with the control group,the ratios of FEV_(1.0),FEV_(1.0)/FVC and MEF_(75%) showed obvious difference between category Ⅰ and category Ⅱ + Ⅲ of the silicosis patients in case group.The main types of pulmonary dysfunction were restrictive and mixed ventilation disorders in silicosis patients.The unconditional Logistic regression model suggested that the main risk factors of pulmonary dysfunction were various category of silicosis,medium or heavy smoking,long-term exposure to silica(30 years)and pulmonary tuberculosis.It is suggested that the incidence of pulmonary dysfunction would be increased with the progress of silicosis,in addition,the risk factors of pulmonary dysfunction also involve smoking,long duration exposure to silica,and complications of silicosis etc.