[Respiratory disease caused by MMVF fibers and yarn]

The non-carcinogenic effects of vitreous fibres on the human respiratory apparatus have been the subjects of numerous studies on large exposed populations. No evidence seems to have been produced of the existence of a fibrogenic effect. However, no definite and agreed opinion has yet been expressed by the main Agencies and Institutions working in the field of prevention. As a contribution to the discussion, the paper presents the experience of the Clinica del Lavoro of Milano involving 1000 subjects who underwent broncho-alveolar lavage during assessment and checking for suspected occupational respiratory disease. A group of 23 cases was selected who were exposed to vitreous fibres without other significant exposures to factors considered hazardous for the respiratory apparatus, especially asbestos. We observed 7 cases of alveolitis; 6 cases with pleural thickening; 2 cases of interstitial disease. On the basis of the nature of exposure (duration, latency from beginning and from the end of hazardous occupation), of the data obtained from the examination of the bronchial lavage liquid (presence of vitreous fibres, siderocytes, cellularity), and of the clinical and laboratory data (X-ray, PFR), the view expressed is tendentially reassuring concerning the possible effects of vitreous fibres on the respiratory apparatus. Although the existence of an irritative type of lesion that manifests in the form of alveolitis and localised pleural thickening seems possible, albeit in a limited number of cases, it does however appear much more difficult to admit the existence of a fibrogenic effect.