Document jNBzvnJVEKvBOJeVBjXpOeDK5

PLAINTIFF'S EXHIBIT Projections of Asbestos-Related Disease 1980-2009 Alexander M. Walker, M.D., D.P.H.; Jeanne E. Loughlin, M.5.; Emmy X. Friedlander, M.S.; Kenneth J. Rothman, D.P.H.; and Nancy A. Dreyer, Ph.D.. Approximately 19.000 cases of mesothelioma and 55.000 coses of lung cancer will arise in- US. men with histories of nontrmal occupational exposure to asbestos. There arc approximately 65.000 US. men now alive with clinicoily diagnosablc1 asbestosis. These estimates are based, m the cast of the cancer, on estimates of the effective number f asbestos-exposed workers required to produce the current national incidence of mesothelioma. The asbestosis estimates are based on a number of rough measures relatma thi prevalence of osbestos,s to the incidence of mesothelioma, the incidence of compensable asbestosis in other countries, the prevalence of and mortality from pneumoconioses general!), and the number of workers health exposed to asbestos. Overview The purpose of this report is to arrive at estimates of the number of case* of mesothelioma, lung cancer, and asbestosis which wilt arise in the United Sutes between the years j and 2009 This is a slightly different goal from that of other* who have made similar attempts, generally re stricted to cancers (e.g , Hogan and Hocl 1981 and a num ber of contributors to the ninth Banbury Report, 1981, edited b\ Pelo and Schncidcrman.) Whereas others have tried to estimate the extent of disease attributable to as bestos exposuic, we provide here estimates of the total amount of disease in persons with nontrivial exposure to asbestos VU chose this latter approach because the pro tections were undertaken out of a need to estimate the numbers of lawsuits which might arise from asbestosexposed, ill persons. Since attribution of the cause of an illness is difficult at best on an individual case basis, all ill persons m an exposed population represent potential litigants, and it is their number that we seek to estimate f ram the Department of tpidemiolofY. Harvard School of Pub lie Hejtih, Bovtun, (Dr* totikrr and Rothman), and ipi demiuiojtv Resources, lot , Brooklme, Mass, (Mss LoughJtn and f ncdUndt-r, and Qrs feaUcr, Rothman, and Dreyer), This report as suhmitied to attorneys for the Manville Corpora tion on Aujt 2, 19b2 The version presented here in incorporates a number of minor editorial changes mjde t>\ the authors Journal of Occupational MedicineA/ol. 25. No. S/May 1983 Projection of future cases of mesothelioma and lung cancer depend on a number of steps, all of them starting with the number of cases of mesothelioma occurring in the United Stales. We begin with the cases of asbestos-related mesothelioma occurring in the late 1970s and infer the size of the asbestos-exposed populations which would be required to produce that number of cases. Using actuarial techniques and Johns-Manville (J-M) case data to provide some details of exposure timing, we then back-calcuiate to estimate the size of the original exposed work force from the 1930s on whose remnants are now alive. Again using actuarial method* and drawling on known exposure-disease incidence curves, we then project the number of cases of mesothelioma and lung cancer which are likely to occur in the future in the exposed worker population. Since the clinical manifestations of mesothelioma vary according to the intensity of asbestos exposure, we can make a limited refinement of the procedure above by classifying the projected cases as deriving trom relatively heavy or relatively light exposures. This is achieved b\ comparing the distribution of sites of mesothelioma in known relatively heavily exposed cohorts, such as insula tion workers, in whom disease is peritoneal at least half tne time, with that observed in the United Sutes as a whole, in which peritoneal disease occurs only 10vo of the lime. Projection of the burden of asbestosis in the United States depends both on the rate of occurrence of new dis ease and on the prevalence of old disease, which may or may not yet have been medically diagnosed in any given individual. Accounting for prevalent but as yet undiagnosed cases of old disease is necessary for asbestosis but not for mesothelioma or lung cancer because the latter cancers arc either detected or lead to death (usually both) within a period less than two years after clinical onset of disease. Asbestosis sufferers, on the other hand, may live for many year* with diagnosablc (but undiagnosed) disease and reprevent a large pool of potential litigants who can "be have like" new- eases at ac.y time, simply by being made aware of the nature and probable origin of their disease. We have inferred the number of prevalent asbestosis cases in the late 1970s by two principal methods. In the first, we estimate what proportion of mesothelioma cases have diagnosablc asbestosis, and we compare this figure to 409 006211 the rate at which people with asbestosis develop mesothe lioma. Knowing the approximate number of mesothelioma casei with asbestosis and the rate at which mesothelioma occurs in asbestotics, we can calculate about how many 'asbestosis sufferers there must be in order to account for the observed number of mesothelioma eases occurring among them, in the second method we have drawn on another, independent aspect of the asbcstosis-mesolhelioma relationship. In studies of groups occupationally exposed to asbestos, the death rates from mesothelioma and asbestosis have been found to be nearly identical. Thus, projections of mesothelioma deaths in persons exposed to asbestos can oe expected to give an approximation of th* number of asbestosis deaths. Several studies have provided data o 1 the mortality rate in asbestotics and on what proportion of the mortality is due to asbestos. The number of asbestotics can be inferred from the number of asbestosis deaths and the mortality rales in persons with asbestosis. At this point the asbestosis projections depend on a scientific judgment whi;h has to be made on the basis of very' little directly relevant data. The question is: "Do new cases of asbestosis continue to appear many years after the cessation of exposure or, after a certain lag period, does the occurrence of new cases stop?" Put another way: "Does cleaning up the workplace diminish the risk of those work ers who have already been heavily exposed to asbestos buL as vet, have no disease?"^PrcITmTriafy j-M*data suggest thati t cleaning up the work environment does reduce the risk of i j those already exposed, although not immediately to zero. 1 Asbestosis prevalence projections have been made on the assumption that new cases actually occur through 1984 and that from 1985 on any apparent new cases represent new diagnoses of existent disease. Several other "quick and dirty" asbestosis projection methods are available. These depend on drawing analogies between the United Kingdom anc. the United States on use cf relative mortality figures, and on the extrapolation of data from x-ray surveys of exposed workers. j-M data on women are too scanty to allow any direct estimation of the number of cases in women of asbestosrelated disease. {Less than S% of suits derive from women.) Estimating female disease has to be based on deriving approximate proportionality constants: based on the probable historical timing of female workers exposed to asbestos, the current 5% figure can be expected to decline to nearly zero over the next two decades. The tasks and subtasks which are involved in disease projection are as follows: 1. Determine the effective number of past asbestos workers. a. Determine the number of cases of mesothelioma in the United States, 1975-1979. b. Calculate the fraction of mesothelioma cases with a documentable history of asbestos exposure and what fraction of the exposed are likely to have been heavily exposed. c Estimate the timing of the exposure history for U S cases. d Calculate the number of workers now alive and exposed at different times in the past which would be required to account for the current observed mesothelioma incidence. e. Using actuarial techniques, calculate the sire of the originally exposed worker population which would yield the estimated numbers of currently living, previously exposed workers. f. For exposure in the more recent past {which would give rise to no current disease), estimate ^ exposure which could give rise to future disease. i. Use survey data to estimate exposure histories. ii. Use information on changing workp.ace envi ronments to adjust crude exposure estimates. lii. Adjust all original estimates of the numper of exposed workers so that the total number of cases of mesothelioma being observed is consis tent with tou! estimates of the exposed work force (distant past plus recent past) 2. Project mesothelioma incidence. a. Actuarialiy adjust the size of the exposed popula tion to account fc' future mortality and calculate the incidence of new cases in the reduced exposed populations. b. Examine sensitivity of projections to component assumptions. 3. Project lung cancer incidence. a. As above, adjust the size of the at-risk populations to account for future mortality. Calculate the future incidence of lung cancer as a ftmetion of future age, future elapsed time from firs: expo sure, and the future size of the population at risk, b Compare projected and observed lung cancer figures. 4. Estimate current and future asbestosis prevalence. a. Asbestosis prevalence using mesothelioma mor tality in asbestotics. i Mesothelioma incidence as in (la!, i: Proportion of mesothelioma with asbestosis. iii. Estimate frequency of occurrence of mesotheli oma in asbestotics. iv. Infer prevalence of asbestotics. v. Age the 1980-1984 prevalence group using actuarial techniques. b. Estimate current and future asbestovs prevalence based on the equivalence of mesothelioma and asbestosis mortality. I. Derive expected number of asbestosis deaths from projerted mesothelioma deaths. ii. Compare asbestosis deaths to death rates in asbestotics to derive an estimate of the num ber of asbestotics. iii. Age the current prevalence pool as in (4a!. c. "Quick and dirty" projections i. U.K7U.S. equivalence. ii. Relative mortality data. iii. Extrapolation from x-ray surveys d. Derive a general methodology for predici.ng law suits given propensity to sue and disease pre valence 5. Estimate the amount of asbestos-related disease likely to occur in women. 410 Asbestos-Related Disease/Walker et el 006212' Task la: Determine the number of cases of meso thelioma in the United States. 1975-1979. The National Cancer institute (NCI) has sponsored two major cancer incidence surveillance programs since 1969 The first, covering the period 1969*1971, coordinated existing regional tumor registries and supported the estab lishment of new registries, permitting a direct assessment of cancer incidence for about 7% of the U.S. population; this was the third National Cancer Survey (TNCS). In 1973, the NCI reconstituted the administrative structure of the TNCS to provide fo' an ongoing system of monitoring cancer incidence This new program, named the Surveil lance, Epidemiology and End Results program (SEER) has been in operation continuously since then. SEER reporting regions are Hawaii. Seattle. San Francisco-Oakland. New Mcvco, New Orleans. Utah. Connecticut, Atlanta. Detroit, and Iowa Collectively these represent about 10% of the population of the United Slates. In 19S0, the NCI (Con nells 1980) released a detailed report of trends in meso thelioma incidence based on TNCS 11969-1971) and the firs! siv vears of SEER (1973-1978). The annual agespecific mesothelioma incidence for males in SEER is given in Tabic !, which also provides an estimate of the total numocr of men developing mesothelioma in the United States in 1977 The age-specific estimated counts were obtained b\ multiply rng the SEER incidence rates times the Census Bureau's 1977 estimates of the U S male popula ti in m the various aec categories The implied tola' of about 85*1 new cases of mesolhe(io-.. m L S men in 1977 is probably inaccurate for a numpc' ot reason, and should be adjusted accordingly 1 Compd' s"r of the TNCS (1969-19711 and SEER ; 1973 197S- agr-sianouid./ed male incidence figures shows an overjti rise lrom 0 51 lo 0 88 cases per 100.000 men pe>yea*, app'oximatch a 10 annual increase ftom the midpomi of the TNCS to the midpoint of the reported SEER vea-s M 97 5 7 2 To obtain a 1977 incidence figure, a furtne* 15;. inflation ovc: the SEER incidence would be appr..p*ulc (The 10 annual increase is virtually identical Table 1 - Annual Aft-Specific Mesothelioma Incidence for Metes Aft Group Incident Cites per 100,800 Men per Veer kapfied U.S. Tetei 1977 0 19 *0 24 25 29 30 34 35 39 4044 4549 50 54 55-59 60 64 65 69 70 74 75 79 0 002 0 07 0.20 0 17 0 37 1.05 1.59 2 09 3.37 3.84 5 72 6 34 0 2.0 6.1 15.2 10.2 20.2 58.9 90.8 110 1 147.6 143 6 148.5 100 7 IS3.9 Journal oi Occupational Medicine/Vol. 25, No. 5/May 1983 to the rate of increase in mesothelioma incidence pre dicted by the incidence models constructed for task 2. Tnat model predicts annual increases of 11.2% in 1970, declining steadily to 8.4% in T97S.) 2. Since the SEER regions contain proportionately more shipbuilding areas than the United States as a whole, the 'yfr incidence rales are overstated to lhe extent that mesotheli oma occurs more commonly in shipbuilding areas. SEER data suggest that this it indeed the case. The age-standard- i/ed white male rates for Seattle and San Francisco arc 1,42 and 1.36 cases per 100,000 men annually, while those fo? Utah and iewa are 0.82 and 0.54 cases per 100.000 pci year. A reasonable estimate as to the overstatement of mesothelioma due to nonrepresentative sampling of the ^ United States In SEER overall would be 10%- 15k. with a ' best guess of about 12%. ___________ 3. F inally, the diagnosis of mesothelioma is by no means , easy or clear-cut. Selikoff el al. (1980) maintain that a re- j view of all medical evidence in the deaths of U.S. insulation workers from 1967 through 1976 indicates that of 175 i mesothelioma deaths only 104 (59%) had mesothelioma recorded on the death certificate. This startling figure mav | 1 be due in part to the sensitivity of Selikoff and colleagues ' to the possibility that.a difficuit-to-diagnose tumor mav be I mesotheliomaPHigh DrioTexpecttlioriwotildrender diag nosis of mesothelioma more common than it would other - wise be, even in the most competent hands. Nonetheless, it seems likely that any general surveillance scheme will tend to produce underreporting of rare tumors, espeoalK tho>e with ambigous pathology. SEER diagnostic coding is generally felt to be of much higher quality than death certificate information, but the SEER data are regional ard thev necessarily derive in part from smaller hospitals with less sophistication in diagnosis than is available in cancer referral centers. A reasonable estimate would be tfcu: reporting in SEER is about 10% below the reporting thut would result if all cases were seen in cancer referral cente-j and that the diagnosis rates in referral centers are perhaps 20% below the figures that would be reported bv a diacnuv tic group with a high prior expectation of mesothcliv-n-.u For the purposes of this report, we will regard "mes.ith, noma" as that entity which would ordinarily be d:astno>ar.-. as such m a cancer referral center Combining adjustments for linu trends nontcprescnta- tivencss and underdiagnosis in the SEER data one arrives at a best guess or the numbe of mesothelioma cases - occurring in the U.S. men in 1977 not of 854. but of (853.9) {1.75)/(1.12),'(0.90) * 974 cases. The approximate number occurring in the 1975-1979 quinquennium would be 4.870 Task 1b: Calculate the fraction of mesothelioma cases which have a documented history of asbestos exposure, and estimate what fraction of the exposed are likely to have been heavily exposed. Not all mevoihclioma ovcuis in men with a documentable asbestos exposure history Assuming essentials no asbestos exposure in low incidence SEER regions and assuming thjt the enlue difference in mesothelioma in,.! dense is attributable to asbestos, the differences between the highest and lowest mesothelioma incidence would 411 006213 .LI suggest that 38% of mesothelioma in the high risk areas T'' might be "background" incidence. (The annual incidence per 100,000 white males ranges from 0.54 in Iowa to 1.42 in Seattle; 0.54/1.42 * 38%.) In low incidence areas, the fraction of disease attributable to background would be even higher. Inquiries undertaken among mesothelioma patients have yielded estimates of the percent with an asbestos exposure history running from 16% to 76%, depending principally on whether cases come from areas with ' heavy asbestos-using industries. Table 2 summarises the data from a number of sources. While much of the variation in Table 2 must result from real differences in the asbestos exposure histories of meso thelioma patients from different regions, there mas- also be a substantial variation depending on the group interpreting the exposure history. Table 3 (from McDonald and McDon ald, 1980) illustrates this phenomenon. Three hundred forty-four male cases of mesothelioma were paired with cases matched for age, sex, hospital and year cf death. The comparison cases had died with lung meusta-.es from a nonpulmonary malignant tumor. Job histories were ob tained from interview' of relatives, coded and submitted to four asbestos research centers for inlerpreution. While there was general agreement on the proportion with "defi nite" and "unlikely" exposure to asbestos, there was much less concordance in the interpretation of ambiguous ex posure histories. One center, the Environment Sciences Laboratory of the Mount Sinai School of Medicine, was very much more likely than the others to interpret am biguous histories as "probable" asbestos exposure. The consensus UJ. figures (from centers 2, 3 and 4) in Table 3, when averaged, yield an overall figure for the proportion of male mesothelioma cases with a definite or probable history of asbestos exposure of 54%. This number is in the middle of the range of Table 2, and will be used as a best estimate. The proportion* with definite exposure appears to be about 20%, averaging the figures from all four centers in Table 3. A separate line of observation and inference indicates that the proportion of mesothelioma cases attributable to relatively heavy occupational exposure to asbestos is con siderably less than the 54% with a definite or probable ;f- asbestos exposure history. This is based on the observation of the relative frequencies of involvement of the two major sites of appearance of mesothelioma,, the pleura and the peritoneum. As indicated in Table 4, in heavily exposed industrial cohorts, the peritoneum probably accounts for -v about half of all cases. The most imporunt exception to this pattern arose in a group with what (for an industrial cohort) is an atypical exposure pattern: 75% of the observa tion time in the group of Australian crocidoiite miners reported on by Hobbs et at (I960) was in men with a tou! duration of exposure of (ess than 12 months. There were no peritoneal tumors documented among these men. In groups less heavily exposed, the peritoneum is less fre quently involved, as indicated in Table 5. The least exposed Tibia 2 - Proportion of Mesothelioma Cases With Asbestos Exposure History Reference P * at, 1981 Vianna et al, 1981 Vianna et a!, 1981 Regioa; Subjaets Los Angeles 1974-1978; males New York State excluding New York City; males, 1973-1978 New York State high incidence counties 1968 1978 Source ef Data Case or close relative interview Death certificate, occupational record Patient or first-degree relative interview Proportion of Casts With Asbestos Exposure (%l 69/101 (68) 69/91* (76) 7/193 (35) 24/31 177) 17/31* (55) Tagnon et al. 1980 McDonald et al. 1973 Newhouse and Thompson. 1965 Coastal Virginia 1972-1978; whitt malts All Canada (emphasis on Quebec) 1968-1970 Patients dying at The London Hospital 1964 and tartier Patient or next of kin interview Relatives and fritnds inttrvuw Surviving relatives. . medical rtcords 43/56 (77) 11/69* (161 31/69 *(45) 40/76 (S3) 31/766 (41) * Excluder those (or whom interviewee wit uniurt of work history * Excluder indirect (xposure (t.g., ftmily member of an exposed person) * "Definite" or "probable" exposures ^ Includes "possible" exposure as well 412 Asbestos-Related Disease/Walker et al 006214 groups are the general population series of incident meso thelioma cates, and those cases determined by direct in quin to have had no identifiable asbestos exposure. In these groups, the proportion with peritoneal disease is on the order of lKe (see Table 6). From Tables 4-6, it appears that substantial occupational exposure results in mesotheliomas which are at least 50% peritoneal, and that moderate exposure may result in about 20% peritoneal mesotheliomas. If this is true, then only a small fraction of the total contemporary U.S Tabic 3- Distribution (X) of 11$ Canadian and 1S9 U.S. Male Cast-Centre! Pain Accordinj to the Probability of Occupational Asbestos Exposure as Classified in Four Centers Center^ Definite Cases Controls Asbestos Exposure Probable Passible Casas Controls Controls Unlikely Casts Controls Canada (1960-721 1 2 3 4 11.9 1.1 43.8 31.4 4.3 2.7 40.0 64.9 11.9 1.1 20.5 14.6 21.1 15.7 46.5 68.6 13.5 2.7 29.7 21.1 18J 20.5 37:8 55.7 11.9 1.1 22.7 13.0 22.7 27.6 42.7 58.4 United States 119721 1 2 3 4 1B.2 18.9 24.5 18.9 3.8 51.6 35.2 3.8 1.9 26.4 59.1 n 31.4 18.7 20.8 18.6 28.9 58.9 6.3 34.0 19.5 16.4 19.5 25.1 54.1 3.8 33.3 15.1 22.6 27.0 25.2 54.1 * From McDonald and McDonald (1980) * Centers i indicates Environmental Sciences Laboratory, Mount Sinai School of Medicine, New York; 2, CesondsheitsorganisaTte TNO. den Haas, the Netherlands; 3. Department of Epidemiology & Health, McGill University, Montreal; 4, TUC Centenary Insti tute cl Occupational Health, London School of Hygiene and Tropical Medicine. London Table 4 - Relative Frequencies af Peritoneal and Pleural Mesothelioma in Heavily Asbestos-Exposed Croups Reference Seiikoft. 198C Sst-'ct Papulation North American insulation workers 1/67 12/76 Peritoneal/Pleural/Mixed P-P/Other 112 63 0 0 % Peritoneal or Mixed P-P 64 Newhouse. 1931 English factory workers > 2 yrs exposure 16 to 0 0 62 Newhouse. IS?' Finkeistein, 1931 English female textile workers Canadian workers receiving asbestos disability benefits 8 12 0 4 50 0 0 40 44 McDonald and McDonald. 1980 Insulation workers, asbestos production end manufacture United States end Canada 1960 1972 23 29 0 0 44 Hobbs et at. 1980 times end Simpson, 1976 Miners and millers of crocidohte W Australia 194 3 T 966 Mesothelioma m United Kingdom 1/60-12/69 classified from medical records es "heavily exposed to asbestos" 0 25 0 20 m 6 0 0 0 29 Journal of Occupational Medicme/Vol. 25, No. S/May 1983 413 \ i l y A 0G6215 Tibi* S - Rtlath* Frequencies a( Parheneii end Pteuret Mesothelioma in leas Hwdy Attestet-Eipettd Groups Reference limes and Simpson, 1976 Sourct Papulation Exposed, but not heiviiy Peritoneal/Pleural/Mixad P-P/Otfcer 10 181 13 0 % Peritoneal r Mixed P-P 13 Chovil et al, 1981 "Compensable" mesothelioma in Ontario, including expo sure which was "relatively light, or short duration, in the distant past, or all of these" 9 23 0 0 28 McDonald and McDonald. 1980 Heating trades, shipyards, construction (excluding insulation workers), United States and Canada 1960-1975 19 117 0 0 16 mesothelioma incidence (9io-13-7-c peritoneal) can be attrib utable to heavv occupational exposure: almost about 25% of U.S. cases (the 13% peritoneal and an equal number of pfeurals) can be attributable to heavy exposure. In fact, the true proportion of heavil> exposed mesothelioma cases must be less than 26%, since peritoneal tumors do arise in persons with little or no known asbestos exposure (sec Tabic 6/. The 2O': with "definite" exposure in Table s ma\ provide a more realistic upper limit to the heavily exposed proportion of persons who develop mesotheliot.: Task 1c: Estimate the timing of exposure in U.S. cases. Allegations in |-M mesothelioma case data provide inio'mation on the timing cf asbestos exposure in those persons who develop mesothelioma. There are 278 )-M mesothelioma cases who give an analyzable asbestos expo sure history: a plausible age at first exposure (between 15 and 54 years of age) and a year of first exposure between 1930 and 1954. (See task If for an explanation of the 1954 cutoff.) By five-year age groups we have identified the alleged year of first exposure to asbestos. Applying the percent alleging first exposure at various years in j-M data to the age-specific estimates of asbestos-exposed meso thelioma incidence obtained (after adjustments) from SEER, one can-estimate how many cases of mesothelioma occurred among U.S. workers who were first exposed to asbestos at any given age and any given year in the past. This procedure is carried out separately for the 20% of U.S. cases of mesothelioma with presumed heavy exposure, ana for the 34% with presumed identifiable light exposure, on Table 6 - Relative Frequencies at Feritoneel and Pleural Mesothelioma in General Populations and in Casas INitb No Idtntifiable Asbestos Expossre Reference Source Population PerRonni/Pteuril/Mixed P-P/Othtr % Peritoneal or Mixed P-P Connelly. 1980 Ireslow, 1982a Breslow, 1982a SEER 1973 1978 males TNCS 1969-1971 males US. paltents entering com prehensive cancer centers 1978-1980 43 369 0 S 83 0 36 234 0 55 0 0 9 10 13 Elmes and Simpson, 1976 No known exposure 7 52 4 Q 11 Bans et it. 1979 Turkish villagers in a hyptrandemic area 1 20 0 0 5 McDonald and McDonald. 1980 No occupational axposurt, United States and Canadian cam 1962 1975 37 119 0 0 24 414 Asbestos-Related Diseasa/Wslkcr tt *1 006216 \ the assumptron that the relative frequencies of heavy and Having derived the above equation on the basis of light exposures did not change-greatly until the introduc tion of dust controls in the workplace in the 1960s and Selikoffs data, Peto et ai (1982) examined its generalizability by fitting similar equations, with, the same exponent ju 1970s. Qualitative review of the J-M case data indicates ^ that most current J-M cases are derived from the smaller, (3.2), to data obtained in a variety of settings. Tabic 7 provides, for five studies, the Peto estimate of the leading heavily exposed portion of the workforce (insulation work constant term in the above equation, the number of meso ers, asbestos factory workers, etc.). theliomas observed and predicted al five-year intervals from Task Id; Calculate the number of workers now alive and exposed at different times in the past which would be required to account for the current observed meso thelioma incidence. How many exposed workers are there? This question can be answered b\ combining the estimated counts of meso thelioma cases having each exposure history with data on the incidence of mesothelioma in exposed workers. Peso (Pcio ei a!. 1982) analyzed Selikoff et al's (19S0) data on the incidence of mesothelioma in insulation work er* and found that incidence could be very closely described by the equation (Mjik i<r * r(a?l p,. where / is the number of cases of mesothelioma occurring per year r is the elapsed lime in years since first exposure to asbestos and P; is the size of the population of workers with firs: exposure t years previously. This incidence curve is graphed as a solid line on the Figure for a hypothetical first exposure, and the total number of cases observed. Observed incidence rates from the five studies are plotted on the Figure, along with Peto's curve (with the constant term calculated from Selikoffs data). All show a sharp increase beginning IS years from first exposure and continuing - so far as the data tell - indefinitely thereafter Although Peto's equation has the theoretically attractive property that its mathematical form is derivable from cur rent theories of carcinogenesis, it is not the only possible mathematical description of the U.S. insulation worker mesothelioma incidence. Bresiow (1982a) has used the same data to estimate the components of a second formula which incorporates an estimated latent period as well as the exponential and constant terms used in Peto's formula. The form of this equation was proposed originally by Newhouse and Berry. (1976), and in a statistical sense it fits the observations more closely than does the Peto equation. Using the symbols as above, that incidence equation is: n I * 1.37 X HT* x((- tS)1-M*x/>f. population of i00.000 people. The belter fit of this equation to Selikoffs data derive* principally from the fact that it predicts no cases to occur in the first IS years following first exposure: Peto's equa tion predicts a small number of cases, in fact, in Selikoffs data none were observed to occur. Breslow's function is plotted as a dashed curve on the Figure. The two equation* give very similar estimates. Throughout the ensuing anaK sis, Peto's equation has been used because it appear* to pro vide estimates more consisted with the full range of report ed values (as opposed to Selikoffs data alone). Nonetheless, projections carried out using the Peto equation have ail been verified using the Bresiow equation. As suggested in task la, Selikoffs figures might lead to estimates of more mesothelioma occurrence than would be detectable by competent cancer specialists under ordi- _ ' nary circumstances. Vie have provisionally adopted a y correction factor of 0.8 ir. Peto's and Bresiow's equations ? relating mesothelioma incidence to asbestos exposure. This has the effect of expanding the size of the exposed population required to account for currently observed mesothelioma cases. Given the number of cases which have occurred and knowing their alleged elapsed interval since first exposure, one can solve the equation* above for P,. We carried out this procedure for all five-year categories of age at diagnosis of mesothelioma in 1975-1979. and for all elapsed times since first exposure, giving a matrix of P,\ which corre sponds to the distribution of asbestos workers alive in Soli* line remnants Peto incidence carve (Pet* t al. 1112); 1975-1979, who gave rise to mesothelioma, cross-tabulated dotted tin*. Bresiow incidence curve (Irtciew, 1112). Incidence by age and year of first exposure to asbestos rates reported by feta et at (1112) lor five studies (set Table 7): The size of the exposed population calculated in this gen cirrit h SatikoH et ai (1171); open triangle, Newbousc and step is an artificial figure corresponding to "insulation Berry (U7S). open square, Pete (1110); solid circle, Hobbs at al worker equivalents " That is, the number is the number of (1110). salid square, Seidman at al (1110). Data Irani Pete at ri asbestos workers as heavily exposed as the insulation (1112). workers studied by Selikoff who would be required to Journal of Occupational Mtdicint/Vol. 25, No. 5/May 1983 415 00S217 Title 7 - Uamfctn Flewel (FU e4 Ferhwwji tft) Mrotttliamti. Sett CmM (HI, mi Mw-Vem (MV) if Olwnitio id Vlflees SlPdia: Expected Members (tip) An Obteiaed fey Fitti*| Oeitk Rest** (Turn Sat* Fin* lnwOT),>`wlii > h Caamat* Sn>r Stlikeff tt *1 (1979), North Amtittin msulation workers (mixed exposure, b-4 37 > 10-*) Newhouse end Berry (1976) fxetory workers (mixed **pQiutt,b$-5 110"*1 fete 119101 chrysolite tttMt fKlO'y (b>2 94 i 10-`) Hobbs e; it 11980' Auttra'ien croeidoMe mtntn (0*5 15 10'/ Sf^rniP ft |t (19791, U S amos'tr factory I0' 91 * 10 * ' Vim Fhst Expanw* it- 16- 26- M- 3S- 48- * TtW ft 2 8 19 20 t 12 2 63 ft 1 14 32 26 IS . 16 7 113 H 3 22 67 41 39 28 8 160 Dio 4-38 22-SS 44-26 41-64 31 17 23 59 1217 180 00 MV 4,639 12113 14,711 8,736 4,311 2428 172 48 812 Ft 1 3 7 S 7 ft 0 3 8 3 K i 6 15 11 12 Exp 2-59 S-32 1837 1214 12-87* MV 18,167 3,438 9.862 6,423 3,772 23 72 45 43 00 48687 Pi 0 0 1 2 ft 0 0 0 0 H 0012 Eip (516 8-5? 1-10 177 MY 1,633 1,160 1.761 MSS ft 1 12 13 ft 0 0 0 H 1 17 13 Sp 4-53 9-37 13-5* MY 27.177 17,017 17,028 2 0 2 1-69 837 * 8 '2 1-32 414 8 0 ffl-44 92 7 0 7 7-00 8.893 26 0 26 2600 56412 F, 0 8 1 3 3 0 ft 8 0 1 2 4 0 h 0 fi 2 5 7 0 Exp 0-38 1-48 2 73 4-01 4-68 8-52 MY 3,678 3,174 2,618 2.826 1.313 68 7 7 14 1400 12527 From Pio tnH1982. * 30 O' mote veers, 37 3 issamed " ct!cu<i"n; expected niimbtr : 30 o> more yean. 77 3 assumed m calculating xpecied number explain the current mesothelioma experience. As outlined ir usk lb. it is likely (Hat only some 37% of exposed meso-. thciioma case, (20:. of the 54*:) actually arise in persons v.,th heass exposure. The remaining cases derive from larger populations with less intense exposure. For the purposes of mesothelioma incidence projections, there is no need to distinguish between the two situations. A population of 100.000 workers at one exposure level can be expected to give rise to the same number of cases as a population of 200.000 at half the exposure. Therefore the "workerequivalent" has an interpretation which is independent of the actual distribution of intensities of exposure. For lung cancer, the distinction does make a difference: the larger population will have a larger "background" number of lung cancers to which the asbestos-attributable cancers must be added In either case, the impression of J-M's legal staff at present is that most lawsuits are coming from heavily exposed plaintiffs, indicating that the distinction may be relevant for a person's propensity to sue. Task le: Using actuarial techniques, calculate the size of the originally exposed worker population which would yield the es timated numbers of currently living, previously exposed workers. Every group of workers now alive with first exposure at some time in the past corresponds to an originally exposed population, some members of which have died with the passage of time We have used white male actuarial survival tables covering the years 1930-1979 to cal.ulate the or' finally exposed population as follows: call the population alive in year y, of age a, with time r since first exposure, Pa,:,} Call the same population t years previously (whethey were a-t years old). Pa.t,0,> -r lf the actuarial prob.bility for survival from age a-t to age a, starting in \ ear > is -Sj-r.a.j-r then Pe-t.O,} * '`a t i where Pa-t,o,> -i IS the number of workers entering the asbestos-exposed work force in vear y-t at age a-t who would be required to produce in year.t a surviving exposed population of size Pa,t.} If that surviving exposed popula tion has already been derived (task Id) as the one large enough to produce the estimated number of new exposed cases of mesothelioma of age a who report having been first exposed to asbestos t years previously, then Pa-i,o,} -r the size of the new workforce t years earlier which would be required to account for the current mesothelioma experience. A modification of the actuarial survival figures was necessary before carrying out the above calculations As noted in task 1b, some 20/54*375* of the insulation-worker equivalents estimated here derived from heavily exposed individuals Sciikoff has noted that insulation workers have a 37% higher overall mortality rate than the general population. As a result, a group consisting of 37% heavily exposed workers has approximately a (37%)(37%) = 14% higher mortality rate than the general population This 416 Asbestos-Rlilted Disa&se/Walker it al correction factor has been introduced into alt calculations of the survival of nondrseased, asbestos-exposed (roups of insulation-worker equivalents. Task If: For exposure in the more recent past which would give rise to no current disease, estimate the quantity of expo sure, since this could still give rise to future disease. The procedures of task Id and le begin breaking down when first exposures less than 20 years prior to the 19751979 period are considered. Few cases of mesothelioma would have as yci arisen from this period, because of the dclased rise in the mesothelioma incidence curve; thus it is impossible to work backwards to the exposed popula tion with am rcliabilttv. Instead, we have used the re ported distribution of age at first entry into an asbestos- related industry from a survey of men aged 40 and above conducted for )M by the firm of Eirick and Lavidge. Al though that survey does not allow us to calculate the absolute number of heavily exposed asbestos workers entering the workforce each year, it docs allow us to calcu late the relative number entering. Altogether the Eirick and Lasidgc survey identified 214 individuals who had worked in an asbestos-using industry, of whom 79 were aware of actual exposure to asbestos dust. The results of the survey were as shown in Table 8, from which it is apparent that the distribution of years of entry into asbestos-using in dustries is essentially identical for men who did recall and those who did not recit< direct asbestos exposure. We have based our adjustments on the larger, statistically more stable numbers of all entrants into asbestos-using industries. The workforce was calculated directly from the meso thelioma incidence data through 1954. From 1955 on we assigned numbers proportional to the number of men in the Eirick and Lasidgc surves reporting entry into the work force m each quinquennium. Adding the post-1955 workers generally resulted in a small increase in the predicted num bers of mesotheliomas for 1975-1979 Both pre- and post-1955 figures were then iteratively adjusted until: (1) the pre-1955 figures maintained the year of first exposure distribution implied by the J-M eases, (2)*tNe:posM955 figures stood in the proportion to the pre-1955'that was dictated by the survey, and (3) the 1975-1979 mesotheli oma predictions derived from the resulting distribution of exposed workers equaled the number actually thought to have occurred. From 1965 on, it is probable that exposed workers faced diminishing amounts of ambient asbestos fiber. We have accounted for this by recalculating the overall work force size (as above) but with smaller fractions of the exposed workforce assigned to the post-1955 period (In effect this amounts to modeling the health effects of an unchanged number of workers exposed to less and less asbestos by assuming smaller and smaller numbers of work ers exposed to essentially the same amount of asbestos.) Workforce discounts used to compensate for recent im provements in The workplace1 were: 1960-1964, 10%; j 1965-1969, 50%; 1970497*, 75%; 1975-1979, 1005:." Table 9 gives the number of insulation-worker equiva lents entering the workforce for each quinquennium 1930-1974, as estimated from J-M data directly through 1954, and with adjustment of the post-1955 figures to match the survey data in their calendar year distribution. Of particular interest is the general conformity of the worker distribution for earlier years (as inferred from J-M data) to that actually observed in the Eirick and Lavidge survey. Table 9 also gives the number of insulation-worker equivalents entering the workforce in each quinquennium from 1930 to 1979, according to intensity of exposure For the heavily exposed group, one equivalent can be taken to equal (more or less) one worker. For the iess heavily exposed group, there may be as many as five or 10 actual workers making up each insulation-worker equivalent. Task 2a: Adjust exposed population and calculate future incidence of mesothelioma. For every five-year period in the future, we calculated the number of mesothelioma cases that would be expected to arise out of each group of workers we estimated to have entered the workforce at each age-of-entry in each calendar- Vear Before 1930 1930 1934 1935-1939 *940 1944 '945 1949 ,130 1954 `"is 195S I960 1964 '.96b 1369 I97Q 5?74 *5.".- ;*;9 Tablet - Veer af Entry Into the Asbestos-Exposed Workforce member Workers Whe. Recalled Ashfstes Exposert % Cumulative K Number All Workers In Asbestos-mini Industries % Cumulative % 5 6.3 1 1.3 6 7.6 17 21.5 14 17,7 5 6.3 10 12.7 9 11.4 7 i.s 1 1.3 4 5.1 6.3 7.6 15.2 36.7 54 4 60.8 73.4 84,8 93.7 14.9 1000 16 7.5 9 4.2 19 8.9 45 21.0 29 13.6 19 8.9 29 13.6 21 9.8 14 6.5 5 2.3 8 3.7 7.5 11.7 20.6 41.6 55,1 64.0 77.6 87.4 93.9 96.3 100.0 Journal of Occupational Medicina/Vol. 25, No. 5/May 1983 417 00G Table f - Tkt OituoiiMtiM ! Asbestas Expocaea j Insufetien-Wotfcer Equivalents Enuring tba l. laber Fare* Maav% Exposed* LWrtv Expand* Total 4 1930-1834 1839-1939 1940 1844 1949-1949 1950-1954 1955-1999 1960-1964 1965-1963 1970-1974 2,700 13,100 55,900 35.400 36.100 34,900 22,700 8,600 1,400 3,700 11,100 74,900 43,300 59.400 49.300 32,100 12,200 2.100 MM 31,100 130,900 85,300 7,560 14,200 64,000 20,100 3,51)0 Table IB - Projected Numbers of New Mtsothriisma Casas 1II9-200I m dee With Plausible Asbestos Exposure Using Twe Models of Incidence Mo Latency Parted (Peta) Latency Parted (Breslow) 1980-1984 1985-1989 1990-1994 1995-1999 2000-2004 2005-2009 3,200 3,500 3,600 3,400 2JOO 2,100 - 3,400 3,900 4,200 4.000 3,500 2,500 Tatal 1980-2009 11,790 21.560 * In the huvily exposed, each insulation-worker equivalent corresponds roughly to single worker 1 Many lightly exposed individuals are required to make up i single insulation-worker equivalent (listed in the table) $ The total number of insulation-worker equivalents, not the total of exposed workers quinquennium in the past. Using the notation of previous sections, call a the age in 1975-1979, and t the number of years elapsed since first exposure in year y. Call p the number of years into the future for which a projection is being made. Then the age at first exposure is (o-t), age in the projected future year is (o+p). and elapsed time from first exposure in the future is (t+p). The components of the projection equation (Peto el al, 1982) are: (<t*p.r>p - The number of new cases of mesothelioma p years from 1975-1979 among persons then aged (a+p) with time elapsed since first exposure (t+p). Pe-i,0,y ~ The number of persons entering the asbestos workforce t years prior to 1975-1979, at age (o-t), in year y. Se-t,o+p y ~ Actuarial survival from age (o-t) in year y to age (a*p), taking into account recorded actuarial survival for calendar years p> >r to 1979, and assuming age-specific mortalities after 1979 to be unchanged from their late 1970s values. K - A constant term derived from Selikoff's observation of insulation workers (Peto et al, 1981), 4.38 x 10~* for one-year incidence, 2.19 x 10'7 for five-year incidence, multiplied by a correction factor (0.8) for higher diagnosis rates in Selikoff 's data. The projection equation is: f*p,t*p * P*-t,0,y * T-t,**p,y * A * (f*P)s* The estimated populations of exposed workers presented at the end of task 1 in Table 9 yield projections of meso thelioma incidence shown in the first column of Table 10 for the years 1980-2009. Use of Bresfow's projection equation to derive the ex posed population and the resultant mesothelioma incidence leads to very similar protected counts, as seen in the second column of Table 10 Redefining K to equal 1.37 x 10s, again multiplied by an 0.8 correction factor, the Breslow protecting equation is 'e+P,t+p " t*a~t,0,y * $e-t,fp,y * * * (r*P~l S)1**4*, Task 2b: Estimate the sensitivity of mesothelioma projections to the assumptions involved. Assumptions underlying the mesothelioma analysis fall into two categories, depending on whether they are re flected in the final mesothelioma projections in a linear or nonlinear fashion. The linear factors affect the height of the projected curve, whereas the nonlinear factors affect its shape. The linear factors are those of task la (corrections of trend in incidence, nonrepresentativeness of the SEER populations, general underdiagnosis of mesothelioma) and task 1b (fraction of mesothelioma cases exposed to asbes tos). While the net effect of uncertainties in these elements s^-may be as much as 30% either way, it is crucial to bear in mind that the ultimate projections of mesothelioma law suits must be tied to the number of suits currently occur ring in relation to the number of cases of disease occurring ("propensity to sue") so that these variations in absolute incidence have no final effect on projections for numbers of lawsuits. Nonlinear effects, because they affect the shape of the future mesothelioma curve, are highly relevant to projec tions of suits. The shape of the curve is relatively robust to large variations in the nonlinear parameters. Assuming that the reported years of first exposure to asbestos in the j-M tiles were off by five years in either direction gives very distorted year of entry distributions (with peak employ ment coming before or after the war) and only shifts the incidence peak forward or backward five years, but does not change its broad, relatively flat character ("hanging the age distribution of current mesothelioma > (in the SEER data) by assigning 309*more cases to and er or to the under 50-year-old age groups show u similar five- year shifts in the incidence peak. Assuming that the work place was entirely cleaned up by 1965 slightly increased the short-term projections for mesothelioma and decreased the long-term ones, since the effect of recent exposures (or., nonexposure) can be expected to be felt only many years in the future. Assigning all worker-equivalents the higher mortality of insulation workers leads to slightly faster decline in the pool of exposed workers, and a 5%- 10% drop in late (post-year 2000) estimated mesothelioma incidence. Assuming that mortality of exposed workers is that of the general population leads to a 5% increase in late .ncsothclioma incidence. 418 Asbestos-Related Dueass/Wilker et al 00S220 Task 3a: Adjust the size of the exposed population and calculate future incidence of lung cancer. The incidence of lung cancer among asbestos workers has been reasonably well documented by Selikoff et al (1980) and others (Berry 1980, McDonald et al 1980, Henderson and Enterline 1979) to be the product of two ermv. the "underlying risk" for lung cancer that would hold in the absence of asbestos exposure, and a multiplica tion factor resulting from exposure. The underlying lung cancer risk is a sharply rising function of age. From the 1973-1978 NCI report of the SEER program the underlying risk for white males is as given in Tabic 11 The asbestos-multiplier calculated by Selikoff et al varies not with age, but with elapsed time since first exposure. Values for the multiplier are given in Table 12. Although the data which Selikoff has assembled on insulation workers represents the largest, statistically most reliable source of fo'iow-up information, there have been a numbe- of other studies of exposed cohorts. These are summarized in Tabic 13. Among all occupational groups, insulators are matched only by factory workers for their levels of lung cancer risk. Miners and, even more so. ship yard workers have much lower risk multipliers, the former possible because ambient fiber concentrations are lower in mining than in processing jobs, the latter almost certainly because the category "shipyard worker" includes many people with minimal exposure. . The multipliers observed by Selikoff are unlikely to be `purely the result of asbestos exposure. To the extent that j the asbestos-exposed workers studied by Selikoff differed in tneir smoking habits from the general population, the multipliers include this effect as well. If part of the purpose of the projections was to estimate what fraction of cases in exposed worker were actually attributable to asbestos exposure, lick of smoking data from Selikoff's workers would represent a serious lack. In fact, the purpose of the projection is to decide how many cases of lung cancer occur in toto among exposed workers. For this purpose, it is suffi cient to assume that the workers observed by Selikoff have approximately the same fraction of smokers as do asbestos workers in general. This appears to be a reasonable assump- Table 11 - lacitftnc* ef Lung Cancer - Underlying Risk Aft fyrs) Maw Casas f Lung Canon par 100,000 Whitt Man par Year 20-24 25-23 30-34 35 39 4044 4549 50-54 55 59 GO 64 GS 59 70 74 76 79 0.2 0.6 2.6 7.4 22 J 58.3 106.8 111.7 214.2 400.9 481.5 19 0 TaWa 12 - SatikoN Asfcastos-MvRiptier* Tim* Silica Fir* Exposure, yrs Kttltiplication Factor 10-14 15-19 20-24 25-29 30-34 35-39 4044 4549 2.55 3.40 3.48 S.00 6.08 5.68 4.93 3.89 From Selikoff et el (1980) tion, even for future projections. Although there has been a decrease in adult male smoking in the United States, the trend appears to include blue-collar workers to a smaller extent than others (Surgeon General 1979). Selikoff's multipliers above describe the experience of aN. cohort of workers with lifetime exposure to asbestos, and j may not correctly predict.the future experience of workers, after occupational exposure to asbestos has been curtailed.^ Observations in chrysotile miners (Berry 1980; McDonald" et al 1980) and asbestos factory workers (Henderson and Enterline 1979) have lent strong support to the idea that relative risk for lung cancer (i.e., the multiplier) may be nearly linearly related to accumulated asbestos exposure over a fairly wide range. Selikoffs multipliers can be in terpreted as reflecting a reasonably steady rise through working life with a decline beginning around the time of retirement, that is about the time of cessation of asbestos exposure. We have incorporated this phenomenon into the projection equations by constraining the lung cancer multipliers for. each exposure cohort to decline from their 1975-1979 value at a rate of 10>c per quinquennium, it should be noted that while this discounting of later multi pliers fits the Selikoff data most closely, there is no a priori reason to expect a decline, and mathematical modeling of other, smaller bodies of data does not suggest a decline. While the values used represent our "best estimate" for projections, experts who disagreed would probably choose somewhat higher multipliers and consequently would pro ject somewhat larger numbers of cases. The projection equation has the following components: t**p,t*p - The number of new cases of lung cancer p years from 1975-1979 among-persons then aged (a+p) years with time elapsed since first exposure {t*p\. Pa-t.O.y -- The number of persons entering the asbestos workforce l years prior to 1975-1979, in year y at age (o-t) ^a-i.o-p.y - Actuarial survival from age (a-;) to age (u+p), beginning in ycary. L9*p - The underlying risk of lung cancer as deter mined from NCI tables for white males of age {o+p). M( - Lung cancer risk multiplier for elapsed time since first exposure through 1975-1979 (r), reduced by lOSo for each subsequent quinquennium. The projecting equation is ^ Journal of Occupational Medicine/Vol. 25. No. 5/May 1983 419 006221 ffinirntyw Table 13 - Risk Multipliers for Lung Cancer From Cohort Studies* Minimum (Years FaSosMitg Exposure) Maximum (Years Following Exposure) Insulators, Setikoff at a111980) Factory workers Henderson and Enterline (19791 Mewhoust and Barry (19731 Peto at al (1977) Cement workers Huges and Weill (1980) Snipyard workers (except insulators). Kolonel at al (1930) Mi. ers McDonald at al (1980) Nicholson tt at (1979) Hobbs at tl (1980) 0 1.8 2.42 1.25 0.77 1.1 0.80 ... 2.10 (<10) t (<2)* (1M<) (10-15) (<10l teD* ... 10-5) 6.03 7.78 638 1.71 3.33 1.3 2.65 4.19 2.46 (30-341 t (>2)1 (>20l (30-35) (>10) {>201* (4049) (*15) in each study, if avert! exposure levels were given, the highest is reproduced here f Time dtti not given separately from accummulatad dost exposure i Tine figures ere for years of employment c~r r~F ~ ^a-t,0 * Sff't'O+p * t-c*F * Mi+p- The projected incidence is calculated for each worker group- entering the workforce at every age in every past year, and the projected number of cases occurring in every fne-vear period are summed. The projection procedure described above is by itself correct only for a heavily exposed worker cohort {such as insulation workers or factory workers). For a less heavily exposed cohort such as shipyard-workers, the projection predicts only the asbestos-attributable disease, plus the background lung cancers which would be found rn a popu lation whose sue corresponds to the number of insulation worker equivalents. When the insulation-worker equivalent exposures are spread out over a larger number of persons, more background disease needs to berecognized in oroerio project the total burden of lung cancer (both spontaneous and asbestos-attributable) in asbestos-exposed persons. Table 14 presents projections of lung cancer for a worker population which on the average is about one half as intensely exposed to asbestos as insulation workers. Since our best estimate is that 37% of the "insulation workerequivalents" are indeed heavily exposed, this implies that the remaining 63% of equivalents arise in workers whose exposure intensity is 2.6 limes less than that of an insula tion worker among the 349 J-M cases aged 40-79 who filed suit claiming lung cancer in the years 1975-1981, and who further gave a sufficiently detailed exposure history to allow- them to be classified. The percent distributions are further crossclassified, by the age at which suit was filed. `> parallel are the age-specific distributions of years of first exposure to asbestos for the 22,248 male lung cancer cases for the period 1975-1979 predicted by the model developed in tasks 1 through 3. Lung cancer is less well connected with asbestos exposure than is mesothelioma, both in the medi cal and in the legal communities, and so there may be an increased element of serendipity in bringing cases of disease to litigation. Nonetheless, there appears to be a fair correlation between the observed and predicted distribution of years of first exposure, particularly in the overall fig ures. Although the lawsuits labluated do not represent the iota! number coming in to J-M (most do not have detailed asbestos exposjre data), their distribuiic-n over age cate gories reflects a plausible pattern of litiginosity when Table 14 - Projected Numbers of New Lung Cancer Cases 1000-2009 in U.S. Man Plausibly Exposed to Asbestos Yaer No. al Naur Cases Task 3b: Compare projected and observed lung cancer figures. Since no part of the model used to predict lung cancer inc dence is based on data from lawsuits coming in to )-M. if is possible to test partially the validity of the pro jections by company details of the |-M litigation file against the model s projections. Table 15 displays the distribution of alleged year of first exposure to asbestos 1980 1984 1985 1989 1990 1994 1995-1999 2000 2004 2005 2009 Total 17,800 13,600 10,200 7,000 4,300 2,200 15,100 420 Asbestos-delated Disease/Walker etai Title IS' le*f C*car Percent OHtribwtton ef Veer * first Exptfurt ta Attest** Pitewcn Alt)< m lewisit* (If7S ISIIUntf tttixxti fcy Meld (1179*tt7l> Aft it Odfftoy) /Itwitm 4049 r SO 55 Hi 69 70 79 . TOU tt L M l V l 1930 1114 tiisim 2 7 27 00 ) 6 88 0 27 4.7 19 9 3,9 11,0 7 1 (7 tti >0 * 3 7 t? 0 t 8 SJJ me t9u 13 5 8 783 20 3 33 1 35 1 33 3 SCO 1 40 3 104S-1940 10S0 1IS4 8 1 35 1 18.7 30.7 23? 110 tss 20 7 22 3 10 1 76 3 14 5 14 3 7 t 20 3 121 20 1 15 2 117 15 1 10SS10S0 1IJ 28 2 SO 23.0 ee 15 4 71 3 *9 10 6 1860-1884 11 15.5 S.7 UA 4.7 1.8 7.1 0 57 3.8 Ttd 1865 1118 1870-1874 % Cmk 8 ? , 27 *Wic 37 46 07 toco 698 2.5 SB 100 0 122 2.1 0 1 100 0 3770 t 4 X 4 TOC G U 0 0 100 0 8312 ? 1 c 100 0 4? 0 0 100 0 9443 32 11 100 0 3*5 05 00 1800 222<8 * i (Mu ? w ;v *ry/ifc * ftponi't (*t 1! JW V mace p'o-e^o-'i o`lor*--lyrnDtr lun; uncr cans imrng in iibesios f*poud men tn the United Sims compared lo the proieclcd distribution of lung cancers. The highest propens-t\ to sue appears to be in the 40-49 year age group, with a gradual tailing off to age 69, and a pre cipitous drop tnereatter Task 4: Estimate current and fuiure asbestosis prevalence. Lnitkc persons with mesothelioma or lung cancer, per son* wiih asbestosis are likels to live mans years after trie onset cf their disease Much or all of that lime they may be unaware that their ssmptoms are due lo asbestosis. From the pom; of view of medical and legal awareness of the V, disease, then, the key event in the progression of a case of 1 asbestosis is not the date of onset, but rather the date of diagnosis For predicting the rates of diagnosis (and hence suit the key underlying figure to examine is the prevalence of potentially diagnosable cases in the general population. There are no direct measures of the prevalence of diagnosablc asbestosis in the United States. There are, however, methods of arriving at educated guesses. One depends on the occurrence of mesothelioma in persons with asbestosis; anothcr depends on an equivalence between asbestosis mortality rates and mesothelioma mortality rates. Task 4a: Predict asbestosis using mesothelioma mortality rates in asbestotics. Elmo and Simpson (1976) have reviewed the clinical, pathologic and radiographic records of 327 cases of meso thelioma occurring in the United Kingdom b- iween 1960 and 1969 They found that 70/247 cases with chest radio graphs f28 vt. J had dear radiog>aphit evidence of concurrent ubeftotit Thu figure / not a biulogtul contUnl; rjthcr it probably reflects the pi'ticular distribution of intensities and durations of exposure to asbestos which U K. meso thelioma cases had undergone in the 1960s. If the general historical pattern of asbestos exposjre in the United States is simitar to that in the United Kingdom, then one may estimate that ahout 28r-t of the cases of mesothelioma in Journal of Occupational Medieint/Vol, 25, No. 5/May 1983 in the United Slates, about 273 developed mesothelioma each year. Three studies give rates of occurrence of mesothe.ioma ir. persons with asbestosis which are of the same ordtr of magnitude. Berry (19S1) provides the most extensive data 25 cases of mesothelioma occurred in 665 Englishmen with asbestosis certified for the purpose of disabii..* insurance, followed for 4,165 man-years of foliow-up between 1952 arid 1976. Thus, he found a rate of one casc per 166 man-years. A total experience about three fifth* as large was reported by Edge (1979) who obsei*ec se*ecases of mesothelioma in 2,637 man-years of observation 429 men who had been identified by chest radiograph* showing pleural plaques taken between 1964 and 1971 in an English shipyard community. His observed rate is one case per 377 man-years of observation. Least iniorrr.ativc because of its small amount of observation is me report of Finkelstein et al (1981) who studied mortalu. among 172 workers receiving workman's compensation for a* bestosis in Ontario between 1942 and 1979 followed for 733 man-years. There weie three death certificate record* of mesothelioma (one per 244 man-years! and siv further cases identified by review of other records (total of one case per 81 man-years of observation). Totaling the experi ence recorded in the three studies, one obtains reports of 41 cases in 7,535 man-years of observation, or one case in 184 man-years of observation. Exclusion of the six Finkelstein cases discovered only after record review would give an overall rate of one case of mesothelioma per 215 man-years We have chosen a figure of one per 200 manyears as a summary figure. Ai with the 28% figure for the frjcuon of meiolhcl'omj cases with asbestosis, the one per 200 man-yean estimate for mesoi1 Jioma in asbestosis should not be taken to be a biological constant. It too probably reflects the distribution the United States in the late 1970s, or about 273 cases annually, had concurrent diagnosable asbestosis. Put anothcr way. of all the people with diagnosable asbestosis 421 006223 Tsfeit IS - Lauf CP*rx*t Bntributisft *f Y*t af fkt! ta AtkcrtaiAAtfatf m Impuku (11711911} l*4 Prttftctttf hy Mttfrf (1f7S*ti?l) A** t Oufntus /(.twwit 4049 t* ftf 90 59 M Ft# 69 L M 1130 1134 113S-113I 27 27 o0 \ s SO 0 27 4.7 tS 5 3.9 no 1*481144 13 S 0 70 3 20 3 33 1 35 I 1145 mi 1*501154 ii 351 IS.7 33 2 23.0 110 195 20 7 22 3 10 I 16.3 14 5 11551151 UJ 21.2 9.0 23.0 S.S 15 4 IHSIIM 1.1 15.5 5.7 11.5 a xs Tflttt tliSIKI 1170-1174 % Cmsi 11. * 46 27 07 100 3 37 10C cse 2.5 01 100 0 122 2.1 0 1 100 0 3770 14 14 100 0 14* 0 0 KMC 6312 70 79 t 71 16 7 33 3 14 3 71 71 7.1 7 1 0 100 0 42 V 0 i 104 5E0 20 3 124 0 0 0 0 1G0 0 *44j Ton l 3 7 120 301 201 152 9 --M ig 331 40 3 117 15 1 10 t ;*iw * * ? y/4b e fioosu'f dtti furred *' Jw V mode p'o.e;t.Dns omou numftft lung tincir cam arising tn tstmtos'tspottd mtft r> the Uwtt0 Sutrs 57 3.S 32 05 1 1 100 0 3<S 00 190 0 2224* compared 10 the proicclcd distribution of lung cancers. The highest propens'ts to sue appears to be in the 40-49 year age group, with a gradual tailing off to age 69, and a pre cipitous drop tnercafter. Task 4: Estimate current and future asbestosis prevalence. Lniigc persons with mesothelioma or lung cancer, per sons with asbestosis are likeh to live mans years after the onset of their disease Much or all of that time they may be unaware that their ss mptoms are due to asbestosis. From the point of view, of medical and legal awareness of the V disease, then, the key event in the progression of a case of ` asbestosis is not the date of onset, but rather the date of diagnosis For predicting the rates of diagnosis (and hence suit the key underlying figure to examine is the prevalence of potentially diagnosable cases in the general population. There are no direct measures of the prevalence of dugnosablc asbestosis in the United States, There are, however, methods of arriving at educated guesses. One depends on the occurrence of mesothelioma in persons with asbestosis; anothe' depends on an equivalence between asbestosis mortality rates and mesothelioma mortality rates. Task 4a: Predict asbestosis using mesothelioma mortality rates in asbestotics. Elmc-s and Simpson (1976) have reviewed the clinical, pathologic and radiographic records of 327 cases of meso thelioma occurring in the United Kingdom tv tween 1960 and 1969 They found that 70/247 cases with chest radio graphs (28-vl had clear radiographic evidence of concurrent asbestosis This figure is not a biological constant; rather it probablv reflects the p>Micular distribution of intensities and durations of exposure to asbestos which U.K. meso thelioma cases had undergone in the 1960s. If the general historical pattern of asbestos exposure in the United Stales is similar to that in the United Kingdom, then one may estimate that about 2S9-t of the cases of mesothelioma in Journal of Occupational Medici nt/Vol. 25, No. 5/May 1983 in the United States, about 273 developed mesothelioma each year. Three studies give rates of occurrence of mesotht. oma ir. persons with asbestosis which are of the sam; order of magnitude. Berry (1981) provides the most extensive data 25 cases of mesothelioma occurred in 665 Englishmen with asbestosis certified for the purpose of disabil.o insurance, followed for 4,165 man-years of foiiow-up between 1952 and 1976. Thus, he found a rate of one case per 166 man-years. A total experience about three fifth* as large was reported by Edge (1979) who obseivec sever cases of mesothelioma in 2,637 man-years of observation .r, 429 men who had been identified by chest radiograph showing pleural plaques taken between 1964 and 1971 in an English shipyard community. His observed rate is one case per 377 man-years of observation. Leas: informa tive because of its small amount of observation is the report of Finkelstein et al (1981) who studied morulit. among 172 workers receiving workman's compensation for a* bestosis in Ontario between 1942 and 1979 followed for 733 man-years. There were three death certificate records of mesothelioma (one per 244 man-years) and six further cases identified by review of other records I total of one ease per 81 man-years of observation). Totaling the experi ence recorded in the three studies, one obtains reports of 41 cases in 7,535 man-years of observation, or one case in 184 man-years of observation. Exclusion of the six Finkelstein cases discovered only after record review would give an overall rate of one case of mesothelioma per 21S man-years We have chosen a figure of one per 200 manyears as a summary figure. As with the 28% figure for the fraction of mesothcliomj cases with asbestosis, the one per 200 man-yea's estimate for mesot' Jioma in asbestusis should not be taken to be a biological constant. It too probably reflects the distribution the United States in the late 1970s, or about 2*3 cases annually, had concurrent diagnosable asbestosis. Put another way, of all the people with diagnosable asbestosis 421 00S224 of intensities and durations of exposure to asbestos holding roughly over the two decades ending in 1975, If, however, we accept the rate of one case of mesotheli oma per 20C asbestotics per year, and combine this with the expected number of mesothelioma-asbestosis cases derived before, i.e., 273, we arrive at an overall estimate of about 55,000 persons with diagnosable asbestosis in the United States in the iate 1970s. Expressed algebraically, the line of reasoning above is as follows, l et / be the annual incidence of mesothelioma in asbestotites; lei A be the number of asbestotics in the United Sutes; let M be the annual number of new meso thelioma cases in the United States; and let P be the proportion of those with concurrent asbestosis, then A x t * M x P and A - M x P/I. Substituting known or estimate values. A * (974)(0.28)/ (1/200); A = 54,544 men with asbestosis. At present it is no' known for how long new cases of asbestosis will continue to develop among currently healthy workers previously exposed to asbestos, assuming that workplace contamination has been essentially eliminated since 1975, ana greatly reduced prior to that. J-M's worker experience indicates that there has beer, a precipitous decline m new cases of asbestosis over the last decade (Chase 1981) This would argue in favor of not projecting the occurrence of new cases beyond 1985. As a best esti mate then, we have based asbestosis prevalence projections on an assumption of continued new occurrence through the first half of this decade Starting from the projected mesothelioma incidence in 1980-1984, we have projected asbestosis prevalence in each age group for 1980-1984 using the proiection equation described above. For projections bevond 1984, we have aged the popula tions using modified 1977 white male actuarial survival figures The modification is based on strong evidence of vers much higher mortality rates in men with asbestosis than m the general population. Berry (1981) reports on 283 deaths in asbestotics with only 108 6 expected; Finkelstem et a! (1981) epert 66 deaths in asbestotics with only y- 16 6 expected Together these give an overall mortality for <J' asbestotics 2 79 times that which would otherwise be expected Table 16 provides our projections of annual diagnosable asbestosis prevalence for each quinquennium through the year 2009 Of particular importance in interpreting Table 16 (and Table 18 rr. the following task) is that the prevalence figures are for clinically diagnosable (not necessarily diag nosed) asbestosis which would qualify for workman < compensation in the United Kingdom or Canada. This is | inescapable, because the only detailed survival figures ] available on men with asbestosis derive from these regis-J tered and monitored groups. Depending on the criteria1 used, very much more "asbestosis" can be diagnosed on the basis of minimal radiologic changes. Table 17 (Selikoff 1976) illustrates the problem. Chest x-rays of 1,117 men were graded according to the degree of asbestosis, classified ' on a four-point scale ranging from 0 (no disease) to 3 (severe asbestosis). The readings were cross-classified b\ time since first exposure to asbestosis. It is very unlikely that workers with Selikoff s minimal (grade 1) asbestosis would qualify for workman's compensation. If such workers were to be included in prevalence estimates, how ever, the projections of Tables 16 or 18 (task 4b) would have to be roughly tripled Task 4b: Estimate asbestosis prevalence using the equivalence between asbestosis and meso thelioma mortality. A second line of reasoning about asbestosis prevalence can lead to an independent estimate by which to gauge the results of the previous task. This is based on the near perfect identity of the time course and magnitude of asbestosis mortality -.id mesothelioma mortality in Seli koff et als (1980) insulation worker data, combined with independent estimates of mortality in men with asbestosis. _ It is of particular importance that the asbestosis mor ,, yy tality recorded by Selikoff is not simply an estimate of mortality in men with asbestosis, but rather specifically of mortality from deaths due to asbestosis. Berry (1981/ found that 56 of 263 deaths (21.3%) in British men with asbestosis were actually attributed to asbestosis. Finkelstein et al (1981) found for the more inclusive category "non-malignant respiratory disease"23of 61 deaths (37.7%/ in Canadian men receiving workmen's compensation for asbestosis. This figure is consistent with Berry 's, which is based on larger numbers and more specific reporting. Independent estimates of mortality rates among asbes tosis sufferers place them at about 2.8 times the corres- ;% ponding age-specific rates in the general population (see task 4a). For any given age group, write the mesothelioma deaths among men exposed to asbestos as M,,, and the corresponding count of all deaths in men with asbestosis as Tebla If - Projections ef the Number of Prevalent Cases Asbestosis in 0 8, Hafts 1990-2009, Projection Based an the Incidence ef Uesetbeliome in Atfcestetics Ttn ie. ef Men Alim With Attestash 1980 1954 198s 1989 1990 1994 1995 1999 2000 2004 2005 2009 SS.BOO 35.400 19.000 9.600 4.400 1.700 422 Table 17- X-Ray Changes in Ashtstes insulation Workers* Veen Since Onset af Espoo* r ie. Percent Distribution by Asbestos Grade 11 2 3 40 4 30-39 20-29 10-19 0-9 121 1.1 28.9 42.1 23.1 194 128 52.6 25.3 S.3 77 272 45.5 22.1 1.2 379 158 41,7 2.4 0.0 346 19.6 11.4 0.0 0.0 * From Selikoff (19761 Asbestos-Related Disease/Walker et al 00S225 >,, Then the Selikoff finding of an equality in the numbers of mesothelioma deaths and asbestotis deaths in insulation workers, combined with Berry's finding that 21.3% of ail death is due to asbestosis, is Ma - 0.213 x Da. If the general death rate for men is G, and the number of asbestolics is A, then the total number of deaths in asbestolics is D,, * 2.8 x G x <4.4 is the number of interest. Combining the above equations, a s 4t,,/(0.2t3 * 2.8 C). Me is available for every age and future year from the mesothelioma projections (usk 2) and G is estimable for each age group from current vital statistics data. Selikoff's data apply to insulatior workers exposed to ^asbestos essentially all their working lives, and cannot, therefore, be expected to give a reasonable estimate of asbestosis mortality for into the future, after the work place has been largely cleared of significant asbestos ex posure. (Mesothelioma mortality, by contrast, is affected almost entirely by age at first heavy exposure, and is not changed greatly by workplace clean-up. at least as far as i concerns already exposed workers.) (The problem is that '"discussed at the end of task 4a: new asbestosis probably * stops occurring (with some lag. perhaps 10 years) after the cessation of asbestos exposure. Thereafter mesothelio ma asbestosis relations observed previously (under condi tions of extended exposure'! became inapplicable to future v proiectionj As 'ft task 4a, we have handled this problem by estimating prevalence based on continued new incidence through the 1980-1984 quinquennium, and have estimated subsequent prevalence by aging the 1980-1984 population as described in task 4a Table 18 gives the projected asbes tosis prevalence figures for U.S. males 1980-2009, using this second proiccnon procedure. Task 4c: Other methods of projecting asbestosis prevalence. There are several "quick and dirty" estimates of asbes tosis prevalence which give estimates of the same order of magnitude as one another. 1, Berry (1981) reports that 133 workers were certified annually by U.K. pneumoconiosis panels in 1973*1976 and that the median survival of tt c least disabled certified workers was 15 years This gives a maximum steady-state prevalence of 15 x 133 * 2,000 workers in the United Kingdom with certified pneumoconiosis (essentially all Table It - Projections of the Number of Prevalent Costs of Asbestosis in 03. Males 1910 2001, Projection Bast* an the Equivaitoct of Asbestosis and Masethaiiomi Mortality Katas Voars Wo. of Mm Alivt With Asbestosis 1980 1984 1985-1989 1990 1994 1995 1999 2000 2004 2005 2009 $4,000 45,300 11,000 19,700 11.400 S.700 asbestosis). The United States is about four times the size of the United Kingdom. Historical exposure patterns being equal, this implies the existence of about 8,000 asbestotic workers or former workers in the United States. Apart from the looseness of the analogy between the United Kingdom and the United States, this projection suffers from its dependence on the number of w'orkers actually certified in the United Kingdom. This is a lower limit to the number actually ill. 2. Burnham (1982) cites an unpublished estimate of the National Center for Health Statistics (NCHS) that there were 427,000 (range 248,000 to 606,000) pneumoconiosis sufferers in the United States in 1980. He also points out that the Mortality Statistics Branch of the NCHS noted 1,422 deaths ascribed to pneumoconiosis in the United States, of which 72 were ascribed specifically to asbestos. Applying the death proportionality to the pneumoconio sis prevalence gives an estimate of (72/1422)(427,000) = 21.000 asbestotics (range 17,000 to 30,000). The pneumo coniosis prevalence figure, however, was based on only a questionnaire and is therefore likely to be an underesti mate, and the reporting of asbestosis on death certificates is notoriously low. 3. The prevalence of x-ray changes in workers listed in Table 17 can be multiplied by our estimates of the size of the heavily exposed workforce (Table 9), to obtain esti mates of asbestosis prevalence ranging from about 8,000 to 120.000 depending on whether radiologic grade 1, 2, or 3 is used as the minimal criterion for a diagnosis of asbestosis. Although the correlation between x-ray changes and symptomatology is imperfect, the low end of this pro jection (8,000 grade 3 cases) would certainly represent symptomatic individuals in every case. The upper end of the projection (120,000) would include many people with few or no symptoms, whose asbestosis would be detectable by physical or radiologic examination only Task 4d; Derive a general methodology for predict ing lawsuits as a function of asbestosis prevalence. Although it is not the purpose of the present work to derive estimates of a person's propensity to bring suit given that he has disease, the difference between asbestosis and the cancers insofar as diagnosabilily and survival times are concerned calls for some comment. Mesothelioma and lung cancer come to diagnosis fairiy rapidly and reliably, and as a result the propensity to sue can be related directly to disease incidence in order to derive an expected number of lawsuits. Asbestosis is not diagnosed nearly as reliably or as quickly, so that the path way leading from prevalent disease to a lawsuit involves two probabilistic steps: diagnosis and decision to sue. Men with asbestosis live for decades, and so may be diagnosed for the first time and sue years after the onset of diagnosablc disease. Perhaps the best way to interpret overall propensity to sue for an asbestotic man is to calculate an annual proba bility of suing. The pool of prevalent, asbestotic men who arc potential litigants can then be thought of as beir.g diminished with the passage of time through two effects first through their own mortality, and second through their bringing sun. thus removing themselves from the pool of Journal of Occupational Medicine/Vol. 25, No. 5/May 1983 423 003226 potential litigants by becoming active litigants. Over years, then, a constant propensity to sue acts on a diminishing pool of potential litigants to produce a declining annual number of lawsuits. By way of illustration, Table 19 gives the expected number of lawsuits by quinquennium, assum ing asbestosis prevalence pools as fisted in Tables 16 and 18, with cases appearing (and being removed from the pools of potential litigants) at a rate corresponding to suits from 9% of all potential litigants appearing each year. The 9c/c figure was chosen for Table 19 so as to yield current lawsuit rates for the present quinquennium. Bear in mind that the rapid decline of lawsuits in Table 19 is the product of two factors, which hold true only for workers with symptomatic asbestosis The first is the high mortality rate in these men, discussed in task 4a; the second is the finite {though large} size of the pool of potential litigants. From Table 17 it should be apparent that the number of workers with minimal disease {grade 1) is very much larger than the number of genuinely ill workers. If in fact a large number of lawsuits derive from the relatively well, exposed population, neither of the conditions on which Table 19 is predicted would hold: mortally in the minimally dis eased is not much elevated, and the number of minimally diseaseJ persons is so large that current litigation rates will not result in any meaningful depletion of the poo! of potential litigants. Limited J-M data suggest that in fact lawsuits from asbestotics do not decline as rapidly after last exposure as one would anticipate from Table 19, In effect Tabic 19 represents minimal projection. If only a fraction of current cases are coming from symptomatic cases, then the symptomatic pool is being depleted more slowly than projected in Table 19. Symptomatic cases will come in over a large- period, and the remaining, minimally diseased cases will continue to flow in at a rale (determined by sociolegal factors' which is unlikely to be bounded by purely medical or ec u.miologicjl factors such as population mortalityrates or depletion of a pool of injured workers. Taking all of these factors into consideration, a reasonable central projection of the number of lawsuits stemming from ail diseases seen from 1982 on is likely to be about 45,000, with a reasonably Arm lower bound of 30,000 and a veryindefinite upper bound on the order of 120,000 Task 5. Estimate the amount of asbestos-related disease occurring in women. Approximately 5% of the lawsuits being filed with J-M derive from women This number is consistent with an estimate from a variety of sources of about 10% of the asbestos-exposed World War II workforce being female, with a diminished fraction after the war. Exposed female workers still alive can be expected to have an age-at-flrst exposure distribution which is even more concentrated in the war years than that of men. The consequence of this ,s that asbestos-related disease will have reached its peak in women earlier than in men, and is probably past that point already The number of female cases in J-M is too small to make to a direct test of this hypothesis. Probably the most reasonab c protection of female cases would involve accept ing the current 5% figure and projecting and proportion of female cases lu taper oi> gradually to a negligible number by the yt^i 200C 424 TaM# 11 - Projections of Asbestosis Lawsuits Assuming IS of Prevalent Cases (Nontitiganls! Bring Suit Each Year Yosts Method of Projecting Asbestosis Mtso Incidence in Asbestntict Meso-Asbestosis Mortality Equivalence 1980 1984 1985-1989 1990-1994 1995-1999 2000-2004 2005-2009 24,800 1,300 2.800 800 200 too 24.100 10,600 4.500 1,800 700 200 Bibliography Barit Vi, Artvinli M, Sahin AA: Environmental mesothelioma in Turkey. Ann NY Acer! Set 939.423-432.1979. Berry G: Dose response in case-control studies, j Epidemiol Community HtoiOi 10:11-15, 1910. Berry G: Mortality of workers certified by pneumoconiosis medical panels at having asbestosis. Sr / Med 31:130-137, 1911. Breslow N: Unpublished review of NCI data, 1912a. 8 reslow N: Personal communication, 1912b. Burnham CE: Unpublished letter to Norman Bresfow June 2, 1PS2. Chase G: Preliminary Results Prom a Morbidity Study of Do mestic J-M Asbestos Using Locations. Johns Manvilie Corporation internal document, July 30,1911. Chovii AC, McCracken WJ, Dowd EC, tt al: Occupational can cer: Experience in Ontario. 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The Music of Nature The challenge to humanism ... is... to find some new point of view that will accom modate both the findings of science and a sense of commitment to mankind. Instead of viewing ourselves as incidental byproducts of the matter and energy of the universe, we could just as easily think of ourselves as artists creating our own lives, using the material of the universe to do so. There is nothing fanciful or unscientific about this. It is not "incorrect" to see our selves as creative processes using the materials of nature, any more than it is "correct" to talc the reverse view. It's a matter of perspective. Indeed, the gulf between science and humanism may be no more than the gulf that would exist between printers and authors if the printers suddenly insisted that ail litera ture wa> merely a byproduct of the chemistry of ink. The perspective I am suggesting puts the emphasis on conscious life, much as a novel puts the emphasis on the story. The physical universe is the means by which our lives are expressed, the medium through which our stones are told. In adopting this point of view, we can look back over the vast history of the cosmos and see that billions of years were needed to create small amounts of matter complex enough to serve as this medium. Only the incredible intricacy of the material that makes up the human brain could be used to tell the stories of human beings and their loving, caring, hating, fearing relationships with each other. Eons of cosmic trial and error were necessary before that material could exist. There are undoubtedly people who will feel that such a perspective would be de meaning to science. But that would not necessarily be the case. One can cherish physical nature as one would cherish a fine violin, not so much for its shape and color as for the music it produces. - From `'Science and You- New Humanism Musi Deal With Science's View of Man" by Hen. i W. fierce in Pittsburgh Post-Cafette, October 30, 1952. Journal of Occupational Madicina/Vol. 25, No. i/May 1983 425