Document ga6D0JyKNomnGYDwMo9Xqnr5V

773 Differences in occupational mortality from pleural cancer, peritoneal cancer, and asbestosis 4 David Coggon, Hazel Inritip, Paul Winter, Brian Pannett Abstract Objection To mmm whether the increased ritk of disease related to utuHM in occupations from thi eon- atruction and tnglneeilng industries applies equally to pleunl canew, peri toneal renew, and aab--toils, MtdaJwAailyila was baaed on death* among man aged 20*74 In and Wales during 197*40 and 19*2-90. (n - 1 *50 099). Information about couaa of death and thi last fell time occupation of dacedanta ma derived from death cartifi- eataa. Proportional mortality ratio* (PMR*) by occupation ware calculated for each ofpleural cancer, peritoneal cancer, and aahaatoala. flssuft* AllugeUier, 2*4* *** war* attributed to cancer of the pleura, 362 to cancer of the peritoneum, and 2B1 to aabaatoala. Whan occupations wars iwbd according to PMSi ftaan thaao ditoaaoa, striking dUfervncoe ware found. The cairgory of construction worhen which i*w*iwi**t laggwa bad the highest mortality from peritoneal anew (PMR 9*0,04 deaths), but a PMR ofonly 100 (77 deaths) for pleural cancer. In contrast, sevaml occupations with much higher mortality from pleural tumours had no eiccas of peritoneal cancer. PMRs hr aabastoala wliUi more eleealy to those fbr peritoneal than pleural cancer, CnrirfutiYtrir Thaae finding* almost that the sipnanrr rasponsa itiwkwi for di*- eases rnlatril to aabaatua are not all linear, and that risks of pleural mesothelioma may he undsrssHinaiail by simple entrap olation from ohmvatleni In cohorts with heavy exposure, - (Ot&ipRtptimM* 1W5j32:775-77T) One starting point is to identify the occupa tions associated with excess mortality from diseases related to asbestos. During the 1980s, a large proportion of male deaths from mesothelioma in England and Wale* were related to work in the construction and engi neering industries.1 It is unclear whether the increased risk in these job* applies to mesothe* lioma cl the pleura, peritoneum, or both. We have analysed data from the same period that bfcdhw** important differences in the relative frequency of pleural and peritoneal mesothe lioma by occupation, and which may have Implications for control strategy. Method Our analyst wia baaed on ill deaths among men aged 20-74 in Fngiemi and Wale* in 1979-gO and 1982*90. Data for 1981 were unreliable because of industrial action m that year by registrars ofdeaths. Information about die age, until dying cause of death, sod most recent full time occupation of decedents was from death certificates. Causes of death ware coded to the ninth revision of the international chsiifinrion of discam (ICD9), and occupation* were coded initially to the Office of Population Cdimes and Surveys (OPCS> 1980 Classification of occupation*.2 The occupational units defined in the OPCS claasifiratkm were then aggregated into 194 larger job group*.1 For each job group we calculated propor tional mnrtalhy ratioi (PMRs) for cancer of the pleura (ICD-9 * 163), cancer of the peri toneum (ICD-9 - 138-8 and 138*9), and aabeatosh (ICD-9 - 901), with five-year age specific proportions in ail occupations com bined a* th* standard. Confidence interval* (d) fbr FMRs were bated on the Poisson distribution. Kcywonk; ibcnoii atoroUty; mnothcfiomS Occupational exposure to aibcuo* It s major cause of mortality from asbestos*, mesothe lioma, snd bronchial carcinoma. In Britain, legal control* on exposure to asbestos wert first introduced in 1933, and since then have been progressively tighter-d Recent analysis indicate* that mortality from mesothelioma is rising in men at rant ago, and suggests that overall rates will continue to increase through to the next century,1 It h important to ettablish whether this trend result* from inadequate enforcement of statutory exposure Limit*, or whether the Limits themselves are not suffi ciently stringent. Results Over die 11 year period of study 1 656 096 dentil* were recorded in men with adequately described occupation*, including 2848 from cancer of the pleura, 362 from cancer of the peritoneum, and 281 from asbestosi*. The table Hats the job groups with significantly (F < 0*05) raised PMR* fbr *t lesst one of these diseases. The tanking of PMRs for cancer* of the pleura and peritoneum was quite different. For example, construction workers not else where (nec), a group which include* laggen, had the highest mortality from peri toneal cancer (PMR 990, 64 death*), but a I l 3 776 Ceffwt, Inkip, Wum, Jobfmupt wiik tifnificamfy (P<0-03) railed monalifyfrtm umurtftkttirmrV, CeHnrtftkt ptniautm, or aifriioiti JoSrwv Metal plate rnilui Vehicle bwb buildm Phmbm m bh 4n*n Uphchtom nai|Han f^s*^|si] And Qtp(itfi'm,l wfft,* 124-5, mi 12*3, !ll 134-1,139 101-4, 109 104-1, 109-1 I3Q-2, 121-2 120-3,131-4 024-3. OSS-1 >fW"fir "" 9*47 2254 16441 27*3 17429 20917 24S1 3712 *"|-|-- i'J-1----_ ____ _____ Quih pUR ftSKcy 75 TOO 954*4*2 24 440 414-94* 134 430 577-933 14 344 204-444 147 542 304-421 127 34* 2*1-413 14 501 149-90* 15 774 144*44* C_ w1.#^^nKM_M_____ Dtrim PMR (9S%CQ 1 7* 2-432 4 B77 250-2246 11 2S5 141-506 0 0 0-688 6 102 57*221 4 S3 33-313 0 0 0-643 0 0 0-9*7 Wkttm filtcstetl easUHtt (lodoaiibed) Praducaua fiimi Sbcfl atial woriwt Ririfatm mkI Imwlpiaa PnlniitMla|WaMt Cowtfvetiefl wwfctn a*c AnMaUi and mvycil DockaiaadMxUp4(Hta f-|miainl PrttMIMlbN pWCIIICfl gijslfrlm --i MsdWe Wot CVWWWI 124-0.12S QJJ-1.W5-3 I94'*. 1*1-1 tat-9 12447 7404 6312 7050 114-4,117 lJ9-J, 140-J 92304 3104 124-2, 134-1 7941 134-9, 140-9, 140-4 22433 035,030-1,036-2,02*-3, I77B0 030-3,03S-4,0SS-4 (34-12. 143-1. 143-2, 26686 144-2 031-1.031-2.031-3 7463 194-2, 194-3.197-3,197-3 13*03 0CS. 004.190-2,140-3 144*0 0*4-1,04M 42 1M-3,104-3 111-4,1124 2770 90094 54 247 116*330 52 240 144-340 24 340 199-357 51 227 194-323 1*3 2M 109*040 11 ao7 123-327 39 19* 130-274 45 144 12S-313 55 143 121-312 77 140 126-200 21. 140 44-245 34 194 104-214 N 144 105-10* 2 159 17-501 4 133 4*-3* 116 132 104-19* *Ai dctacd n die O^CS 19*0 *--t*--t-- <fMeifufaua. we HttlmtaH ih*^*jjt 1 33 1-114 4 54* 13^790 2 171 21-61* 1 98 1-329 12 105 93-174 3 269 99-773 4 235 64*403 9 9* 32-334 2 44 4-164 44 000 743-1245 1 58 1-134 7 343 47-54Q 9 144 47-541 0 0 0-3049 3 561 114-163* 19 134 76-324 i,,UM. Iv_ DttdH PMR <45* Co 3 2*2 60-S 5 130Z 429-lose 15 457 345-702 00 4 144 40-122 1 30 1-164 1 0 211 0 s-nui o-*u 9 142 34-419 1 77 3-*3* 4 9*4 IOO-4J7 1 74 2-410 17 1*0 110-5*3 0 0 0-431 4 500 63-761 0 0 0-4S 0 0 0-120 71 1503 1345-200* 0 0 0-2*7 4 170 44-499 9 1*0 41-441 3 1314 194-1799 0 0 0-769 11 11* 65-22* PMR of only 160 (77 deaths) for pleural c*- cor. In contrast, several of the occupations with the bihest mortality from cancer of the pleura--metal place workers (PMR 709, 73 deaths), upbolsterea (PMR 366, 16 deaths), carpenters (PMR 362,167 deaths) and electri cians (PMR 349, 127 deaths) had no excess ofperitoneal cancer. , Mortality from asbestoaia was more closely related to that from peritoneal than pleural cancer, with the highest PMR again in con struction workers nec (PMR 1392,71 deaths). The Speannan rank correlation across the 24 Job gronps in the table was 0-43 for asbestosis with cancer of the peritoneum and 0*15 for asbestosis with cancer of the pleura. Discussion In this analysis we restricted attention to the three causes of death that are related most specifically to asbestos. Asbestos also causes bronchial carcinoma, but the effect is Leu discamibla in analyses of occupational mentality because the relative dak is smaller and because associations art confounded by difiermces in smoking and exposure to other lung carcfctogenl in tbc workplace. The analysis was limited by inaccuracies that are known to occur m information obtained from death certificates. Nor all deaths ascribed to cancers of the pleura or peritoneum are mesotheliomas,' and some mesothelioma deaths are classified as cancers of other or unspecified sites.4 Also, some deaths may be incorrectly attributed to atbesioais on die bash of pleunl thickening or plaques, when no fibrosis is protent. Moreover, data were only available on the most recent foil rime fob of deoedems, and some subjects win have beat apoted to asbeitoi m earlier employment about which we had no information. In general, however. the effect ofsuch errors should be to attenuate occupational assodirions, and they would not be expected to have a differential effect on the renting of occupations by mortality from dif ferent diseases related to asbestos. The uk of periodic medical atmuurions or an unusually high rate of necropsies in certain occupation! might boost the demotion of peritoneal men than pleural tumours, but it would not explain audi large discrepancies in the relative fre quencies of these diseases as were found. Nor would it account for die high frequency of deaths from asbestosis in some occupations with relatively low mortality from pleursl cancer, Another limitation was the use of propor tional mortality rather than true death rates. Although PMRs may have been somewhat depressed or inflated by different** in the overall death rates of job groups, the affect should be similar for each ofthe three diseases examined, and again would not explain the contrasting ranking of fobs by PMR. The occupation* with significantly raised PMRs us our analysis were largely the same as those found previously to have high mortality from mesothetiama overall.1 AH entail poten tial exposure to asbestos although in some cases the exposure is related to work in specific industries rather than a general foaturo of die occupation. For example, tb* excess mortality among welders occurred mainly m centres of shipbuilding.* Marry of the high risk occupa* dons are in the construction industry where exposure has occurred from the use of asbestos m lagging *"^ other building materi als. The high PMR for cancer of the pleura in carpenter* Compared with many other build ing trade* may be related to work with asbestos board, Notable for in absence ofsir nificam risk are motor mechanics, (PMR 46, 12 deaths from pleural cancer, PMR 88, thi* deaths from peritoneal cancer; PMR 80, two deaths from asbestosis) about whom concerns hive been nixed because of the presence of asbestos to brake faints. It icons that this exposure has no important effect on mortality from mesothelioma or asbestosis, perhaps because-the asbestos fibres arc modified by heat. The difference in the ranking of occupa tions by mortality from pleural and peritoneal cancer and asbestosis is striking and cannot realistically be ascribed to chance. Nor i> it likely to be explained simply by differences in the types of asbestos to which occupations sit exposed. Ciocidolite and amoshe are more potent causes of mesothelioma than chrysotile,' and all of the occupations with high PMRs from peritoneal cancer could have involved exposure to cTOddollte. But welders, who had a higher PMJt than construction workers nec from pleural cancer, are also Ukely to have had exposure to croddolite (especially those employed in shipbuilding), and yet had a deficit ofperitoneal cancers. A more plausible explanation is tint the exposure-response relations for mesothelioma and isbettoris are non-linear, with the risk of pleural mesothelioma inaeasing relatively more steeply at low exposure* but leas steeply|( high exposures. Where an occupation entails low exposure to asbestos, excess pleural cancer occurs but there is linle effect on peritoneal cancer or asbestosis. With high exposures, the risk of pleural cancer i* increased further, but that of peritoneal cancer and asbestosis goes up much more and becomes dominant. Also, the effect on occupational mortality is diluted according to the proportion of men in the job group who are exposed. For sample, con* ttruenon workers nec include not only laggen with very high ocposuie to asbestos, but alio other occupations such as fioor layers with minims! exposure. As a consequence, the PMRs of the group are reduced fez diseases related to atbesto*. In the case of peritoneal cancer and asbestosis, the risk in laggers is so high that the PMR of the job group u whole remains highest in the ranking. The PMR for pleural cancer is lower and diluted to a level beknV that in occupations such ai carpenters where a larger proportion of men arc exposed, but atlower level. This hypothesis is consistent with findings on the ratio of pleural to peritoneal mesothe liomas in cohort studies of asbestos workers, where peritoneal tumours have tended to be relatively more common in cohorts with longer and heavier exposures,*7 although with occa sional exceptions.1 It alio accord) with the finding of higher fibre contents in the lungs of patients dying from peritoneal compared with pleura] cancer.* It is an indication for caution when extrapolating risk estimates for mesothe lioma at low exposures to crocidoUte and imosite from observations in cohorts with heavy exposure. In particular, the risks of pleural mesothelioma may be underestimated if a linear exposure-response is assumed. This should be taken into account when control limits are reviewed. Wt dunk As OAes tadnua Ccniiun nd Swin far anvidtac as wSA At amnliQr dsn, and Dr Canada MsnuAl w kit kupMI cmmob ea At Amh. Tk* nitjw was n^poml br a pufart a HrtlA rtdSafay EiueaA-t. 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