111. Community Effects of Nonoccupational Environmental Asbestos Exposure
Total Page：16
File Type：pdf, Size：1020Kb
111. COMMUNITY EFFECTS OF NONOCCUPATIONAL ENVIRONMENTAL ASBESTOS EXPOSURE Irving J. Selikoff, M.D., F.A.P.H.A., and E. Cuyler Hammond, Sc.D., F.A.P.H.A. Introduction largely unidentified at present and of unstudied biological importance. THERE has long been curiosity concern- ing community exposure to pneumo- coniosis-producing dusts, partly because Environmental Asbestos Disease the assumed "spill-over" from primary It may be profitable to review studies industrial sources might be expected to of one pneumoconiotic dust, asbestos, in yield information concerning effects of the light of these suggestions. The pos- minimal exposure and partly because sibility of community asbestos disease community studies were needed to give has been known almost as long as base-line data against which to evaluate asbestosis itself. In 1927, shortly after findings in groups of miners living in republication of the case report which these communities.1' 2 Nevertheless, it gave the pneumoconiosis its name,8 Had- was not until the serious consequences dow9 reported finding asbestos bodies in of neighborhood beryllium disease were the lungs of a person living close by an clarified3'4 that the important potential asbestos factory. Other neighborhood of community exposure to pneumo- cases of asbestos disease have been re- coniotic dusts was widely recognized. ported since.10-12 Bobileva, et al.,13 re- In the recent past, there has been ported experiences suggesting impaired growing interest in this problem, rang- health in children living downwind of ing from the health effects on children an asbestos plant in the Soviet Union. of cement and similar industrial dusts The import of such scattered observa- in Rumania5 and neighborhood bys- tions was muffled, however, until the re- sinosis in Egypt,0 to environmental pneu- ports of three germinal studies, within moconiosis adjacent to the Rajasthan a short time of each other: Kiviluoto desert.7 We may anticipate that such (1960)14; Wagner, Sleggs, and March- interest will increase for a number of and (1960)15; and Thomson, Kaschula, reasons. First, because of growing con- and MacDonald (1963) .16 In each, a cern over air pollution in general and pathological "marker," considered al- particulate air pollution in particular; most pathognomonic for asbestos expo- second, because of the appreciation that sure, was unexpectedly found in groups the biological activity of known pneumo- in the general population not known to coniotic dusts is not limited to heavily be industrially exposed to asbestos. exposed workmen, but may affect others indirectly exposed in the community; Stigmata of Environmental Asbestos and, lastly, because study of community Exposure effects of pneumoconiotic dusts may sug- Pleural Calcification - Scattered in- gest methodology and technics suitable stances of calcification of the pleura, for the investigation of other environ- particularly the parietal pleura, were ob- mental factors, including inhaled dusts served in asbestos workers during the 1658 VOL. 58. NO. 9. A.J.P.H. NONOCCUPATIONAL ENVIRONMENTAL EXPOSURE 1930s and 1940s, but their significance another common pleural complication of as a roentgenologic sign of asbestos ex- asbestos exposure but, when diffuse, posure was not appreciated until the re- need not have the same diagnostic sig- port of Jacob and Bohlig in 1955, in nificance as calcification. However, such which such calcification was described fibrosis may occur in more or less dis- in approximately 5 per cent of 343 Dres- crete plaques, and Kiviluoto has called den asbestos workers.'7 Investigations attention to these as additional pleural since then have demonstrated the ex- stigmata of asbestos exposure.20 traordinary frequency of this finding Pleural Mesothelioma-Neoplasms of among asbestos workers and have em- the pleural surface in association with phasized a cardinal feature-that it is asbestosis have been known for over rarely seen in less than 20 years from 30 years. Weiss suggested an etiologic onset of exposure (Table 1) .18 relationship in 1953,21 but such pro- Kiviluoto discovered 499 instances of posals faced the difficulty of infrequency such calcification during a community of reported cases and the absence of epi- x-ray survey among 6,312 adults in the demiological studies to suggest that these Kuusjarvi commune in Finland. Struck were other than chance associations. by this, and the absence of any such cases Wagner's report changed this. He in- among 7,101 adults in the neighboring vestigated 33 cases of diffuse pleural Ilomantsi commune, he astutely ob- mesothelioma in the North Western Cape served that the first commune contained Province of South Africa (an asbestos- an asbestos mine and postulated that the producing area) and in 32 cases demon- people with calcification (farmers, strated at least suggestive evidence of housewives) had been subject to endemic potential asbestos contact, usually non- environmental asbestos exposure.'4 His occupational, as, for example, residence countrymen, Laamanen, Noro and in an asbestos area.15 Since this report, Raunio, subsequently reported air diagnosis of pleural mesothelioma has studies showing asbestos dust at dist- been a signal to seek previous asbestos ances up to 50 km from the mines, in- exposure. cluding deposits ranging from 1.52 gm/ Asbestos Bodies in General Popula- 100 m2/month 4 km away to 34.6 gm/ tion-Asbestos fibers when in the lung, 100 m2/month at 0.5 km.19 have the capacity of becoming charac- Pleural Plaques-Pleural fibrosis is teristically coated; these fibers form Table 1-Time of onset of radiologically evident pleural calcification among 1,117 asbestos insulation workers Years from Chest roentgenogram onset of % calci- Grade of calcification exposure No. normal fication 1 2 3 40+ 121 42.1 57.9 37 20 13 30-39 194 65.4 34.5 46 15 6 20-29 77 89.6 10.4 8 0 0 10-19 379 98.9 1.1 5 0 0 0-9 346 100.0 0.0 0 0 0 Total 1,117 96 35 19 SEPTEMBER. 1968 1 659 asbestos bodies which, when seen, can studies of Newhouse and Thompson.28 hardly fail to attract attention. This was Investigating 76 mesotheliomas at Lon- so even before asbestos disease was don Hospital, they found 31 occurred known (Marchand, 1906).22 Thomson in asbestos workers. Of the remaining took advantage of this phenomenon to 45, 20 occurred in individuals living demonstrate the frequency of inhalation within half a mile of an asbestos fac- of asbestos by the general public. He tory or in the household of an asbestos examined smears of lung bases in 500 worker. Similar findings were reported consecutive autopsies in Cape Town, and by Elmes and Wade in Belfast.29 Thom- in 26.4 per cent found asbestos bodies.16 son's observations have also been con- While asbestos bodies do not have the firmed: 25 per cent to 50 per cent of same significance as calcification or adults coming to autopsy in Pittsburgh,30 mesothelioma (disease may be absent Finland,31 Miami,32 Montreal,33 New and no conclusion concerning time of in- York,34 and Belfast,35 are now found to halation can be drawn), Thomson's ob- have asbestos bodies in their lungs. servations have been very important in demonstrating the frequency of commu- nity exposure to asbestos at present in Table 2-Observed and expected number many areas of the world. Simultaneously of deaths among 370 asbestos insula- these observations raise the serious ques- tion workers during the 52-month tion whether inhalation of presumably period from January 1, 1963, through April 30, 1967. Expected numbers are small amounts carries a concomitant based upon United States mortality risk of widespread community asbestos data disregarding the smoking habits disease. of the subjects. Recent Epidemiological Observed Expected Investigations Cause of death deaths deaths Stimulated by the above observations, studies of environmental asbestos dis- Total, all causes 94 47.5 ease have been extended. First, the re- Total cancer (all sites) 49 8.6 lationship of mesothelioma to asbestos Cancer of lung, pleura, has been clarified. Peritoneal meso- bronchus, and trachea 27 2.3 thelioma has also been shown to be as- Bronchogenic sociated; Enticknap and Smither23 found carcinoma 24 * Pleural 9 such tumors in 52 consecutive autop- mesothelioma sies in one asbestos factory. Large col- 3 t lections of asbestos-associated meso- Peritoneal mesothelioma 7 t theliomas have been published.24-26 The Cancer of stomach 3 0.6 significant incidence of asbestos-related Cancer of colon mesothelioma has now been demon- and rectum 5 1.2 strated in our laboratory. In a prospec- Cancer of all other tive 52-month study of 370 experienced sites combined 7 4.5 asbestos insulation workers, from Jan- Asbestosis 15 0 uary 1, 1963, to April 30, 1967 (sur- Heart and circulatory vivors of a larger group of 632 fol- disease, including lowed 1943-1962), there were 94 deaths. stroke 22 28.5 Ten were due to mesothelioma, three to All other causes of death 8 10.4 pleural and seven to peritoneal27 * United States data not available, but figure should (Table 2). be only slightly less than 2.3. t United States data not available, but these are rare Perhaps more germane have been the causes of death in the general population. 7660 VOL. 58, NO. 9. A.J.P.H. NONOCCUPATIONAL ENVIRONMENTAL EXPOSURE Problems and Perspectives comitantly we are investigating occupa- tional and other characteristics. Prelim- The foregoing overview indicates that inary data suggest that unrecognized at least one pneumoconiotic dust, asbes- occupational sources may add to, and tos, may be widely disseminated into override, general community asbestos the general community from industry exposure (Table 3). sources or end-product use; that such 2. The existence of wide potential for dissemination may produce detectable direct or indirect occupational exposure disease; and that methods to study the has not been considered sufficient, question can be designed.