Flow-volume, spirometric parameters and chest X-ray examinations were obtained in 162 workers exposed to diatomaceous earth dust and in a group of 81 healthy subjects for comparison.
The dust contained from 66.5 to 74.1% of SiO2. Smokers were found in 74.5% of the workers and in 77.3% of the control subjects.
Pneumoconiosis were found in 18% (27 cases) of the workers by chest X-ray examinations. The grade of their pneumoconiosis were all mild (25 cases of PR1 and 2 cases of PR2).
Eight workers were obstructive (FEV1%<70%), one case was constrictive (%VC<80%) and one case showed mixed disorder in spirometry. The mean value of FEV1% in male workers of age-group 50-55 years was lower than that of the control subjects.
In flow-volume test, the mean values of V50 in male workers of age-group 50-55 years and in female of age-groups 30-39 and 40-49 years, were lower than those of the control subjects. Furthermore, the mean values of V25 in male and female workers of age-group 40-49 years, were lower than those of the control subjects. Those differences were statistically significant.
Nevertheless, mean values of ratios V50/V25 of workers were not different from those of the control subjects by each sex and by age-group.
Comparison of pneumoconiosis group (20 cases) and no-finding group (69 cases) in respiratory function tests were not different in male workers of age-group 40-55 years.
On the basis of our observations, we recommend the use of the flow-volume parameters (V50 and V25) in respiratory examinations in workers exposed to diatomaceous earth dust.
