抄録
The purpose of this study was to define respiratory function abnormalities in workers exposed to diatomaceous earth dust.
Flow-volume and spirometric tests were performed on 89 workers exposed to the dust and 40 healthy farmers who were used as a control group. All subjects were males ranging in age from 40 to 55 years.
The dust contained 66.5 to 74.1% Silicondioxide (SiO2).
Workers were divided into two groups; one group included 20 workers with pneumoconiosis and 69 workers without as had been diagnosed by chest roentgenographic examination.
No significant differences in the mean values of age, height or weight were observed between the three groups.
The mean working years exposed to the dust of workers with pneumoconiosis was 25.5 years and that of workers without pneumoconiosis was 22.5 years.
There were no significant differences in smoking habits between the three groups.
The following results were obtained:
1. Significant differences were not observed in rates of coughing, expectorating sputum, wheezing or of shortness of breath among the three groups.
2. For the ten respiratory function indicators FVC, %VC, FEV1, FEV1%, PFR, V50, V50/ht, V25, V25/ht and V50/V25 differences were not significant between those workers with and those without pneumoconiosis.
3. Of the above ten indicators, mean values for V50, V50/ht, V25 and V25/ht for workers with pneumoconiosis were significantly lower than those for the control group.
4. Of the above ten indicators, mean values for FEV1%, V25 and V25/ht for workers without pneumoconiosis were significantly lower than those for the control group. The mean value of V50/V25 was significantly higher for workers without pneumoconiosis than for the control group.
5. A comparison of the ten indicators between workers exposed to the dust and the control group, suggested that V25/ht was the most useful in predicting respiratory function abnormalities.
6. To examine both workers and control groups, the most appropriate screening level of V25/ht was 0.82L/sec/m.
These results demonstrated that workers with a long exposure to diatomaceous earth dust showed significant respiratory function abnormalities even though they had not been diagnosed as pneumoconiosis patients as such by chest roentgenographic examination.
