Residual fibre lung burden among patients with pleural mesothelioma who have been occupationally exposed to asbestos.
To evaluate the lungs asbestos fibres concentration in participants with malignant pleural mesothelioma (MPM) who have been occupationally exposed.



The lung samples were obtained from pleuropneumonectomies or autopsies of 271 male MPMs. The lung samples were examined through scanning electron microscopy. Retrospective assessment was used to assess for asbestos exposure. This study includes 248 MPMs with an occupational exposure defined as either 'definite' or 'probable' or 'possible'.



The participants had finished working in asbestos exposure conditions more than 20 years ago (on average 26.1±11.0 years). The fibre burden resulted with a geometric mean equal to 2.0 (95% CI 1.6 to 2.4) million fibres per gram of dry lung tissue. The burden was higher among participants employed in asbestos textiles industry and in shipyards with insulation material, if compared with construction workers or non-asbestos textile workers or participants working in chemicals or as auto mechanics. 91.3% of MPMs had a detectable amount of amphibole fibres. A strong lung clearance capability was evident among workers exposed to chrysotile fibres. Owing to that, the 1997 Helsinki Criteria for occupational exposure were reached in <35% of cases among participant working in construction, in metallurgical industry, in chemical or textile industry and among those performing brake repair activities.



The MPM cases are now occurring in Italy in participants who ceased occupational asbestos exposure decades before the analysis. A large majority still shows a residual content of amphibole fibres, but given the lung clearance capability, attribution to occupational exposure cannot rely only on fibres detection.
Venetian Mesothelioma Registry, Occupational Health Unit, Local Health Authority of Padua, Padua, Italy.
Enzo
E
Merler
Centre of Electronic Microscopy, Lombardy Environmental Protection Agency (ARPA), Milan, Italy.
Anna
A
Somigliana
Venetian Mesothelioma Registry, Occupational Health Unit, Local Health Authority of Padua, Padua, Italy.|Epidemiological Department, Veneto Region (SER), Padua, Italy.
Paolo
P
Girardi
Mesothelioma Registry, Occupational Health Unit, Local Health Authority of Brescia, Brescia, Italy.
Pietro Gino
PG
Barbieri
D000368:Aged; D000369:Aged, 80 and over; D001194:Asbestos / Q000009:adverse effects* / Q000302:isolation & purification*; D005260:Female; D006801:Humans; D007407:Interviews as Topic; D007558:Italy; D008168:Lung / Q000473:pathology*; D008175:Lung Neoplasms / Q000139:chemically induced / Q000473:pathology*; D008297:Male; D008654:Mesothelioma / Q000139:chemically induced / Q000473:pathology*; D000086002:Mesothelioma, Malignant; D008875:Middle Aged; D019016:Mineral Fibers; D009784:Occupational Diseases / Q000139:chemically induced / Q000473:pathology*; D016273:Occupational Exposure / Q000009:adverse effects* / Q000032:analysis
D019016:Mineral Fibers; D001194:Asbestos