Respirable crystalline silica exposure-response evaluation of silicosis morbidity and lung cancer mortality in the German porcelain industry cohort.

OBJECTIVE: To quantify silicosis and lung cancer risks among porcelain workers occupationally exposed to respirable crystalline silica. METHODS: We reread historical radiographs to identify silicosis and estimated exposure on the basis of detailed work history and about 8000 industrial hygiene measurements. Cox proportional hazards models estimated risks by cumulative and average exposure. RESULTS: Adjusted silicosis hazards ratios were 5.3 (95% confidence interval [CI], 1.6 to 17.3); 7.3 (95% CI, 2.6 to 20.8); and 6.8 (95% CI, 3.0 to 15.3) for cumulative exposures >4 to 5; >5 to 6; and >6 mg/m-years, and 3.3 (95% CI, 0.8 to 14.7), 13.6 (95% CI, 4.2 to 44.4) and 23.2 (95% CI, 8.2 to 65.8) for average exposures >0.1 to 0.15; >0.15 to 0.2 and >0.2 mg/m, respectively. Exposure was not associated with any cause of death including lung cancer. CONCLUSIONS: Respirable crystalline silica exposure more than 4 mg/m-years (cumulative) or more than 0.15 mg/m (average) were strongly associated with silicosis, but unrelated to lung cancer risks.

Esophageal pressure method and impulse oscillometry to assess mechanical properties of the respiratory system in healthy men.

BACKGROUND: Lung elasticity can be assessed by pulmonary compliance using the esophageal pressure method, but this technique is invasive and time-consuming. Impulse oscillometry has been established as a non-invasive method to describe mechanical properties of the respiratory system and preliminary data suggest that it may be used as a marker of lung elasticity. Therefore we compared impulse oscillometry and pulmonary compliance in healthy subjects. MATERIAL/METHODS: In 31 healthy male volunteers aged 20 to 25 years we performed pulmonary function tests including spirometry, bodyplethysmography and pulmonary compliance by the esophageal pressure method. Impulse oscillometry (IOS) was used to determine capacitance (X 5 Hz) and resistance (R 5 Hz and R 20 Hz). RESULTS: Mean dynamic pulmonary compliance was 2.53+/-0.58 l/kPa and mean static pulmonary compliance was 2.82+/-0.85 l/kPa. R 5 Hz and R 20 Hz were between 0.14 and 0.49 kPa/(l/s), while mean X 5 Hz was -0.08+/-0.02 kPa/(l/s). There was demonstrated a highly significant correlation between impulse oscillometric capacitance X 5 Hz and pulmonary compliance parameters. CONCLUSIONS: The results of the present study suggest that impulse oscillometry may be used as an alternative for the invasive esophageal pressure method in determining pulmonary elasticity.