Abstract

Introduction
A group of hard-metal dust exposed workers suffer from cough and chest thightness without any signs of respiratory disease found in common occupational screening programs.

The aim of the study was to detect an early adverse effect of chronic inhalative molybdenum and hard-metal dust exposure in those workers.

Patients
43 employees of a hard metal plant, chronically exposed to hard-metal and molybdenum dusts and 23 healthy individuals without inhalative exposure were examined.

Among the workers, 33 were suffering from cough and chest thightness whereas 10 were not symptomatic.

Methods
Chest X-rays were seen by two independent pulmologists. Spirometry was performed on a Jaeger spirometer. Bronchoalveolar Lavage cells were spun into slices and stained May-Gruenwald-Giemsa

Inhalative exposure was confirmed by electron mycroscopy of BAL fluid. A higher percentage count of macrophages correlated with a decrease of carbon monoxyde transfer coefficient (KCO) (r=0.58, p<0.01). None of the investigated individuals showed firm radiological signs of interstitial lung disease

Conclusion
Chronic hard-metal and molybdenum dust exposure causes respiratory symptoms and a relative increase in inflammatory BAL cells in a subgroup of employees with no functional and radiological signs of respiratory disease.

The cellular patterns we found in BAL in the group of symptomatic workers are similar to those found in patients suffering from interstitial lung disease, but of a more moderate extent.

Respiratory symptoms in "healthy" workers are related to a change of BAL cellular patterns and therefore have to be considered as an indicator for an early adverse effect.

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