Document g2ND6p8687kaaqDp8N59G2Jjq

\\ IIU>NMLV*! AL HLWCAMCIl 5, S i0--210 (1972) Provalence of Pleura! Calcification in Persons Exposed to Asbestos Dust, and in the General Population in the Same District : - M. NaVXUTII. ANI) F. Twite Institute of Hygiene mid Epidemiology, Dci>ortmcnt of Industrial Hygiene and Occuttational Discotcs, Srobdrova 48, Prague 10; end District Ihsjntal, Department of Lung Diseases, Symburk, Czechoslovakia Received November 17, 1971 * It is of interest wlicthcr pleural calcification w primarily the result of long years of exposure to asbestos dust or whether there are /actors other than ex* posvtrc to dust. Wo havo Investigated persons working for a long period in a plant processing aOwslos products (chryxotiie), persons without occupational exposure to dust hut living in the vicinity of the plant, and consanguineous relations of patients with pleura] calcifications. We have also studied a large population above the age of 40, in lltc district in which tl*c plant is situated. Con.parison of the groups disclosed that prcvali-nco cif pleural culcificalions was closely related to opportunity for expis- sure to avifcstos dust either occupationally or by family or neighborhood contact, as contrasted with theTimejeposod population. Tho prevalence In the grotip with direct or indirect asbestos exposure wuf 5.3, 5.8, "3.55; whereas In tlio unexposed population it was 0.345. These results indicate that asliesito* is primarily responsible for pleural findings, hut tlutt su::.u pleural disousc may bt the result of tire other factors, still not known. The identification of other causes is hampered by the long period which need elapse from the onset of Use,.prooeas..to the radiological .appearance'of the pleural;6hange.v- ''X: " 6 V-* ' Soon after die demonstration of thefibrogenic properties ol asbestos clinical evidence appeared demonstrating pleural changes in persons with long work...; exposure in asbestos mines or factories. The unusual finding of pleural calcifica- tion was attributed, in the fifties, solely to the effect of asbestos [Cartier. (4),' % Lynch and Cannon (12)]. Later, when unexplained fiudings of the same char acter were made in the populations not known to be exposed to -asbestos, the etiology seemed less certain [Jacob and Boblig (9); Anspach (1); Anspach, Roitzsch, and Clauswitecr (2); BohIig (3)]. ` Epidemiological studies of populations designed to investigate possible ex- . posures to asbestos dust led in the sixties and later to sharp differentiation of both points of view. In the first instance, are Finnish, Canadian, American and other investigators who believe.that occupational or^nonoccupational ^exposure. jX^asbestoc proyide/.the^baekgr^'^^^pl^?fl ffe^|ng^KjvUuof^t30,'T1) T v; Raunlo''(16); Cartit? (5); Sclikoif (19j;,'2ol6v, Bourilkov, and Babaljov (21); Itubirto, Condna, and Scansctti (18)]. In the second group are authors who describe regional concentrations of pleural calcification with no evident contact . _ with asbestos and who, for this reason, reject an asbestos etiology. Prominent ss iaj.ivShi thtt^socond group are Czechoslovak workers (Hroniek (8); Marsovj (Id;; 1872 !>y Academic Press, Lie. .Hf'SX: &b00 SCF-FA-6655 Ml PRODUCED BY FORD