Document 3Noon7GRMMGe54vNO12Kzeqj0

98 Morris Greenberg and T. A. Lloyd Dories Number of cetev Other Jinrholpoiin Number of cotes small proportion of subjects. Of the 50 subjects with `definite mesotheliomas', where the types of asbestos to which they were exposed were known, 45 had been exposed to crocidolite. Of the group of 12 subjects diagnosed as `definitely not mesothelioma' in which types of asbestoi to which they had been exposed'were known, eight had been exposed to crocidolite. There is no significant difference between these two groups. In four cases of definite mesothelioma no exposure was known other than to chrysotile. A history of exposure to talc was obtained in seven subjects with definite mesotheliomas, but six of them had also been exposed to asbestos. It was not possible to identify the nature of the talc to which they had been exposed. no. 4. Definite pleural mesothelioma: duration of occupational exposure to asbestos. survival after first exposure in the two groups (mean age: UICC, 37-4 years; other pathologists, 38-4 years). The interval between last handling asbestos' and death was under one year in about 40% cases but varied up to 52 years (one case). The duration of exposure was more widely spread, ranging from three weeks to over 50 years. Twelve per cent ofcases had been exposed for under five years. The man with only three weeks' exposure died over half a century later. Table 7 summarises information regarding the type of asbestos, but this could be obtained in only a Other evidence of asbestos exposure It is apparent that.a history of occupational exposure to asbestos is frequently associated with the presence or asbestosis, asbestos fibre bodies, asbestos fibres or pleural plaques observed at necropsy or radiologically (Table 8). Ashcroft and Heppleston (1973) stress the importance of phase contrast microscopy and electron microscopy in searching for asbestos in tissues. The presence of pleural plaques does not always indicate asbestos exposure (Rous and Studeny, 1970). It is not possible, however, to observe a significant difference of asbestos exposure between subjects with definite pleural mesotheliomas and those subsequently categorized as definitely no! pleural mesothelioma. In four `definite pleural mesotheliomas' corrobora tive evidence of asbestos exposure was found in the absence of occupational exposure histories. Of those subjected to 'hobby' or 'domestic' exposure (six cases) none showed corroborative features. Of those with 'neighbourhood' exposure (eight cases), two had nsbeslos bodies. TABLE 8 Corroborative Evidence or Asbestos Exposure1 related to Occupational Exposure History and Notifications to Mesothelioma- Register (Pleural Tumours only) Occupational asbestos exposure history Definite Possible Nooe uccminsble ,. Definite pleural mesothelioma Corroborative evidence No corroborative evidence Not reported 100 (9%) % (JOTO 4 (I3T0 24 0*50 4 (2JTO 18 <j;o 22 (UTO 4 (2JTO 10 (31 *0 Definitely not pleural mesothelioma Corroborative evidence No corroborative evidence Not reported 19 (73 TO 0 (-) 0 < --) 3 (UTO 3 (o;o 6 (33JO 4 (UTO 2 (40 TO 12 (50 ' 'Aibcitotii, atbestos bodies, asbestos fibres or pleural plaques Geographical dl Tables 9a and million per yea diagnoses in E. The Registrar employed for EDunbanonshirt Hamilton, and no mrans reU western Engta' thousands, had 2-97 cases/mill' population of histories of occ remainder of population, pit only four had: asbestos (a rs Assuming that: twin that numb, year. Geographical Greater London Rest of SE Engli SE Lancashire ci Merseyside conn Rest of NW Eng Tyneside .. Rett of N Ensle W Yorkshire eoi Rest of Yorks A N Wales SE Wales.. E Anglia .. Clydeside1 Rest of Scotland SW England E Midlands W Midlands cot Rest of W Midi. England, Wales Standard regiu. Dunhannnthirt 'One subject nh