Cross-Sectional Study on Nonmalignant Respiratory Morbidity due to Exposure to Synthetic Amorphous Silica

Objectives: The aim of this study was to assess the health impact of chronic exposure to synthetic amorphous silica (SAS) on nonmalignant respiratory morbidity. Methods: We used multiple linear and logistic regression models and Monte Carlo multimodel analyses of two exposure scenarios to evaluate the effect of cumulative exposure to inhalable SAS dust on symptoms, spirometry, and chest films in 462 male workers from five German SAS-producing plants. Results: Exposure to SAS was associated with a reduction in forced vital capacity (FVC) in one of the two exposure scenarios but had no effect on forced expiratory volume in 1 second (FEV1) or FEV1/FVC in either exposure scenario. Monte Carlo analysis indicated a decline in FVC of -11mL per 10 mg/m(3)-years exposure (-6 to -0.4). Chest films showed no evidence of pneumoconiosis. Conclusion: This study provides limited evidence of minor dose-related effects of chronic exposure to SAS on lung function.