[Correlations between chest X-rays, clinical data, and lung function tests (flow-volume curve) in asbestos workers...

This study concern 61 asbestos workers, exposed to very dusty conditions, but exposure is stopped for 4 years. Flow-volume curve shows a decrease in flow, at low-volume, particularly in old subjects, with a great dust index. In 13 subjects (21%), with normal chest radiographs, we observe a decrease in flow. This is interpreted as an airway obstruction, and it is an early effect of asbestos exposure. This obstruction concerns the small airways because the Vmax is density independent in the last portion of the VC. Flow-volume curve breathing helium oxygen mixture is not more sensitive, than breathing air. So, this test seems sufficient, to monitor the exposed workers, in epidemiological studies, and prevent repeated chest X-ray examinations which may be dangerous.