perlite and Pneumoconiosis

A review of chest films from 152 workers who had been employed five or more years in perlite mining or processing showed none with small opacities of profusion 1/0 or higher. There were 14 films with doubtful changes (0/1), but these showed no correlation with type or duration of employment. Pulmonary function was measured in 122 current employees from the same plants. Multiple regression analysis showed no significant association between years of employment in perlite and either forced vital capacity (FVC) or forced expiratory volume (FEV1). There was a significant association between pack-years of cigarettes and both measurements. In 66 workers tested in 1975 and again in 1983, there was an average annual decrease in FVC of 32 mL, with 26 mL predicted by the Knudson formula, which is based on nonsmokers. The average annual decrease in FEV1 was 24 mL with 26 mL predicted. Comparison of groups with differing smoking patterns showed that the decreases in both FVC and FEV1 were associated with smoking. The 28 men who had added four or more pack-years in the interval between tests showed decreases in FVC and FEV1 of 44 mL/year and 31 mL/year, respectively, with 26 mL/year predicted for both groups. Those with less than four added pack-years (which included 26 nonsmokers) had decreases in FVC and FEV1 of 23 mL/year and 19 mL/year with 26 mL/year and 27 mL/year predicted.

Topics: Adult; Aluminum Oxide; Animals; Female; Forced Expiratory Volume; Guinea Pigs; Humans; Male; Middle Aged; Occupational Diseases; Pneumoconiosis; Radiography; Rats; Regression Analysis; Respiratory Function Tests; Respiratory System; Risk; Silicon Dioxide; Smoking; Vital Capacity

Chest roentgenograms of 240 perlite workers employed for 1 to 23 years in the industry, showed no evidence of pneumoconiosis associated with perlite exposures. One individual, found to have simple pneumoconiosis, and one found to have complicated pneumoconiosis, had formerly been diatomaceous earth workers. Since only 28 of the men had been in the industry over 15 years and only seven for 20 years or more, continued surveillance is essential to make sure that there are no effects with more prolonged exposures. Studies of pulmonary function of the individuals who have had relatively long exposures are needed to supplement radiographic evidence.

Topics: Aluminum; Aluminum Oxide; Dust; Environmental Exposure; Humans; Male; Maximum Allowable Concentration; Pneumoconiosis; Radiography; Silicon Dioxide; Time Factors; United States