Document 2L94vx10vwzoVQM0J7Djxv8a

I' l \I Mortality Among Employees I of PVC Fabricators Iroiurd Chiazze, Jr., Sc.O.; William E. Nichols, Ph.D.; and Otto Wong, Sc.D. A cross-sectional mortality study of 4,341 deaths occurring jmong current and former employees of 17 PVC fabricators during 1%4*1?73 is presented. The objectives are: (II to iden tify any angiosarcoma deaths among the employees of these Ubricators. and (2) to esamine the distribution of deaths by cause. No angiosarcoma deaths were found among the study gtoup. Sex-race-cause-specific Proportionate Mortality Ratios rut's) were computed, using the corresponding U.S. mor tality as the standard. Among white employees, there appears to be an excess in total cancer mortality, particularly that of the digestive system. Observed deaths were found to exceed the expected in cancers of the breast and urinary organs among white females. Deficit mortality was observed in rrhosis f liver among both male and female white emJ pioyees. lanuary 1974 disclosure of three deaths from ang>satcoou of the liver in a single vinyl chloride polymerization plant j and the attention focused on this new occupational disease are | well known. A significant amount of information from animal exI prrimentation and observation on humans engaged i the produc tion of vinyl chloride followed ' However, there was no informa tion regarding the possible adverse effects on employees engaged m polyvinyl chloride (PVC) fabrication, where potential exposures were thought to be low and to result from the release of unrear ted monomer trapped in the resin This issue was competed of creat import because of the very large number of workers beWved to be engaged m fabrication In March 1974. representatives of PVC producers, who ae 'hembers of the Organization Resources Counselors IORCI. Oc cupational Safety and Health Standards Croup contacted ORC about the feasibility of a study of health risks to employees workmg with vinyl chloride and polyvinyl chlorxie. Since the National tastitute for Occupational Safety and Health (NIOSHI was con ducting a study of vinyl chloride and resin producing emplovers. the scope of the proposed ORC study was limited to employees ol ham Ihe Omm ol io-Utisles ind t(HtwneWixv. Dr(l*itnwm ol CnrwwMr 'Hrnr and Mimilvul MnMi Cwvxmown Unmui Schmd d iwarrv ViUwigton. DC Moot t>s CUwr and WwC 4d Oxansrai-m Irma re Cavi -rkn. he . WtOwiginn DC HOT* O Nfe*i Journal of Occupational Medicine/Vol. 19. No 9/September 1977 companies engaged in the fabrication of PVC resin into finished products A number of alternative study designs was considered, and it was decided that a proportional mortality study would best meet the urgent need for information. The study concentrated on deaths occurring during the ten-year period 1964-1973 among ac tive fabricating employees plus retirees. Since it was not possible to identify those employees with only vinyl chloride exposure, the study focused on deceased employees who worked anywhere in those plants where PVC fabrication was carried on. The primary objective of the Study was to determine whether or not any angio sarcoma deaths had occurred among employees of the fabricators under study. A secondary objective was to examine the distribu tion of alt deaths by cause. The relatively few producers of vinyl chloride monomer and of PVC resin are generally medium to large companies. PVC fabri cators however, range from large plants of ma|or companies to verv small |ob shops. Even in a targe plant there may be few em ployees who are m the vicinity of PVC resins. The range of com pany plant size and number of exposed employees help 10 explain the wife range of estimates of total employment dependent upon WC iexins Fabrication is geographically disbursed, with at least some operation in almost every state. Typical fabrication products tclude iuatcd wire, upholstery fabrics, floor and wall coverings, pipe and other construction materials, toys, recreational equip ment phonograph records, containers and container lining, and a mvrtad o< novelty items Since the fabrication of PVC resin into tmhrd products is often a part of diversified product lines in a plant raw materials other than resin are utilized. Thus, employees may be exposed to toxic agents other than vinyl chloride. Conse quently m tta current study, it is not possible to isolate only the rttect ot vinyl chloride Some departures from expectation may be due to exposures to vinyl chloride, to one or more other agents, to some combnation or to employee characteristics other than occupation Materials and Methods The decision to focus on a cross-sectional mortality study rattar than on an historical cohort study derived from several con siderations first, the primary study objective was to detetmme relatively quickly whether or not any angiosarcoma deaths could be identified among the study group, and this was best ac complished by examining causes of dcajh among relatively recent 725013 623 Vi iCf u/c:r`vm.tTiL j 17 US. T EB G.,, put ten years! decedents. The desirability of identifying an historical cohort for follow-up was recognized, but it was deter mined that it would not be possible to identify clearly and com pletely the necessary cohort of workers within a reasonable period of time, if at all As a consequence, this study is based upon 4.341 sths which occurred during the period 1964-1973 among current or former employees of 17 companies engaged in PVC fabrication. A total of 5$ plants supplied data on all identifiable deaths since, as was mentioned earlier, it was not possible to iden tify those employees with only vinyl chloride exposure (or the study. In order to be included in this study, a deceased employee fell into one of the following categories: 111 employee died while ac tively employed. (2) employee died after retiring from the com pany with retirement benefits, and (3) employee died after ter minating employment but with vesting in a company-sponsored life insurance plan. Deaths occurring among former employees with less than the number ol years necessary for insurance vesting were not included in plant records and were, therefore, not available for this study. An attempt was made to compensate for at least some of the "leakage" doe to employees leaving the industry prior to the lane they were vested in any insurance program by using the following procedures. Once death records for a given company were iden tified. death certificates were obtained and separated into two groups as follows: (1) all deaths with cancer (ICDA 140-20S up to 1967; ICDA 140-209 for 1968 on), or liver disease UCDA S60-S86 up to 1967; ICDA 570-S76 for 1968 on), or suspected liver con dition mentioned on the death certificate: and (2> all deaths from causes other than cancer or liver disease. Death records men tioning cancer or liver disease and giving a hospital as place of death were segregated and sorted by hospital Where there were several death records for a single hospital or several hospitals m the same area, arrangements were made for a Registered Records Administrator (RRA) to visit the hospitals, review medcal records, c ntact the hospital pathologist and review pathoksgy rco>ds to determine whether there were any angiosarcoma cases as the hospital's pathology records. If so. an attempt was made to deter mine whether or not the angiosarcoma possRsly could be related to vinyl chloride exposure This procedure enabled us to dentrfv whether any employees, who had left the industry prior to vesting in an insurance program and remained m the kxal area, had dwd fr m angiosarcoma of the Irver. The hospital mquey procedures turned up five deaths from angiosarcoma of the kve*. atco*dtg to company employment records, none were employed at any terse in PVC fabricating plants. These deaths were reported to OSMA NlOSH. and CDC for inclusion m the ruumedr angiosarcoma survey. Death certificates not mentioning a hospeal as a ptare of death required an additional step to deteemase whether death occurred in a hospital or if a recent hospitalization had occurred pres* to death. The certifying physician was queried by mail lor in formation on recent hospitalization of the decedent and whrshrs there was any indication that he or she had cancer or Wet disease Additionally identified hospitals were contacted as above Originally, it was planned that death certifxates would be ob tained from life insurance earners. In practice, both company and life insurance records were used because of record retention prac tices and retrieval problems in the insurance earners Alt available death certificates were examined by a trained nosoiognt lor men tion of angiosarcoma anywhere on the certificate, and no angio sarcomas were found on the death certificates Underlying cause of death was classified according to the eighth revision o: ternational Classification of Diseases.1 Over the ten-year period under study, plant size \sa* . have changed drastically in many cases. In one instance a employing 300 employees in 1973 employed fewer than 1964. At the other extreme, one plant employing 5.000 pi-,. ' 1964 had only 2.000 in 1973. Some companies had gone - business. Such developments show not only the rapid taking place but also the difficulty of determining average .r.c.... employment. The 17 companies covered in this report from single plant, small companies (one with 70 employ- multiplant targe companies lone with over 7.000 emptm. Average number of employees clustered between 300 a^ - . Although total employment is difficult to determine preciw\ estimated to have been between 65,000 and 70.000 at the t- 1973 Since the population at risk could not be determined, mu-; rates as measures of risk could not be calculated. Rather were summarized in terms of Proportionate Mortality Ratr.. adfusted for the age distribution of the study group. The Pv,< relative frequencies of specific causes of death by age in a par non population to obtain expected numbers of dca;v that cause m the study population. Selection of an aprycomparison population poses some difficulties since it mi. - . desirable to have a cause of death distribution for a similar ^ . ol workers dying during the same period, but not subiecitsi : . factor under study. But such a comparison population aavailable, and the study used mortality for the United v specific for color and sex, for comparative purposes ' 0<recognized deficiencies, the PMR can provide clues on u. dntitoutions of causes of death where true rates cann.- . calculated. The dtri! given in Tat vest majorit fc.6V for w dembution 4rule emf those aged white woe jc deaths wl ( population proportion ^ population 4 that relatn j0' Wtvle the small for Z 4* imor total Unr n 1 Tables -causes .b * : white mr iH 'i'T rrn n n Results Table 1 gives the distribution of deaths among the emplosrv- rotatory ! fCDA l-` populate | the 17 PVC fabricators within each of the ten years. An increa- ere 54 i the proportion of deaths taking place in later years of the dm- * cee.Oig.| may reflect a variety of factors, such as an increasing emplo-- Run tw j popukttion. less complete availability of records for earlier w. *udy g; f j .in one company, there were no records for the first tcu tty? ten years), increase in duration of exposure, etc. Hon*" thrre n no reason to believe that any unavailable death record- ` | 'Rw dea to 57% earlier years would be concentrated in a few causes and the'1' tsvas the distribution of deaths for those years. Crr ler 1 Some*.. the u t TaW* 1. -- Ohtribotita at Daatha tim*t tmotoyan o( 17 PVC Fabricators by Yaar af Dsatb, 1944-1)73. c h T** (bfft ITU ms ITU mi ITU 1TC9 1THJ ISM ivt 1911 twt to. MS iss *00 <n *99 Uf *s *n us <M 4141 % 15 to sz It IIS 101 101 109 _ 172 It 100 6Z4 Mortality Among Employees ol PVC Fabrtcators/Chiazie, Nichols, a1^ * * 725014 occurred among employees of the PVC fabricators under study. Since no angiosarcoma deaths were found among the employees itudied. the first question has an unequivocal answer. A secondary objective was that of examining the distribution of deaths by cause among the employees under study. Implicit m that objective the question of whether or not that distribution is. m some tense, unusual. There is no unequivocal answer to the latter qiMstion. Whether or not an observed distributnn of causes of death is unusual clearly relates to the standard or comparison population as well as the analytic methodology.4 On the basis of a proportionate mortality analysis, there appear to be excesses in total cancer mortality among both white men and white women in the study, when compared to the distributions of deaths for the total United States specific for color *td sex and adjusted for age. Excesses in cancer mortality appear concentrated in cancers of the digestive system and. in particular, n cancers of the intestine for both men and women. In addition, there is a suggestion that mortality from cancer of the breast and urinary organs among white women employees is higher than that for the total U.S. There are, however, several reasons why Journal ol Oaupational Medicine/Vol. 19. No. 9/September 1977 definitive interpretation is difficult. It has, for example, been suggested that a Proportionate Mortality Ratio based on an exter nal population may not be sufficiently discriminating in screening for potential hazards.' In addition, an analysis using PMRs fails to take account of the absolute risk of dying in the population under study ` Further, a number of studies have suggested an overall favorable mortality for industrial working populations, even in those where well-defined hazards increase risk for a specific cause ' Factors such as these are meant to suggest that proportionate mortality analysis must be interpreted cautiously, with the intention of providing leads for further investigation. Results consistent with those of previously published studies would be of particular interest With no comparable working populations m the fabrication industry, potential contrasts may be found in studies of vinyl chloride workers. Monson. et al. provided a proportionate mortality analysis of 161 deceased workers (all presumably white males) in two plants, one where vinyl chloride monomer is produced and one where it is polymerized into polyvinyl chloride.4 Results of that study suggest a possible excess in total cancer mortality, primarily cancer of the 725017 627 Hver. 'However, there we* a suggestion that cancer* f the king and brain also appeared with excess frequency. The current study, while suggesting an excess in total cancer, particularly digestive cancer, does not clearly point to marked excesses for cancers of the liver, lung, and brain among white men. although the PMRs for these cancers are greater than one. The observed-to-expected 'MRs reported by Monson for vascular lesions affecting the cen tal nervous system, circulatory diseases, and external causes are. similar to those reported here. Tabershaw and Caffey. in a study of workers engaged in the manufacture of vinyl chloride and its polymers, conclude that no specific cause of death was statistically significantly greater than expectations based upon Standardized Mortality Ratios (SMRs) using the U.S. male population as the standard.' 8y other criteria, however, the authors conclude there may be an excess risk for mortality from digestive cancer, respiratory cancer, cancer of other and unspecified sites, and lymphomas. At lower exposure levels, they suggest some excess for cancers of the buccal cavity and cancers of the other and unspecified sites. The current study would seem to indicate that excesses of mot* tality from cancer of the digestive system are not sex-specific and are not limited to liver cancer. The majority of the PMRs for cancer among both white men and white women are in excess of unity. Such results must be interpreted with caution but since they ap pear to be consistent with previously studied workers, they suggest the need for continued investigation. Summary Results of a study of 4.341 deaths occurring among current and former employees of 17 PVC fabricators during the period 19641973 are presented. The study was carried out to determine whether any angiosarcoma deaths had occurred among em ployees of these fabricators and to examine the distribution of deaths by cause. No angiosarcoma deaths were found among the itudy population. Distributions by cause of death among white male and white female employees were compared with those for the entire US-, specific for color and sex and adjusted for a* . means of Proportionate M rtality Ratios. There appears to r. important excess in total cancer mortality among both while. and white female employees with digestive cancer, pan*, that of the intestine, contributing to the excess. Amonc women employees, cancers of the breast and urinary organ. also be in excess. No excesses were found for diseases oi th culatory system. There were deficits in mortality from cirthrv the liver among both male and female employees and a dw. accidents, poisonings, and violence among men. The use nProportionate Mortality Ratio based on an external sun-, requires caution in interpreting these results, but the need m- ther investigations is indicated. OHSPAC 0HSP Thu study "'ll spomrxed try the (allotmg organttationt: Ament in Cm C-- ft F Coof^rh Company. Dumond Stamrock Corporation, Fv^tton# W j**: Company, (ohnt Mirrvtfl*, Motor Vthcfe Mnu(4ctun Auocmcav* OwmcjJ Company. Union CAftnde Corpotttion, UnrovAl tocorpnrttfd QCCU! References 1 Selikoff II end Hammond EC (Eds.): Toxicity oI vmvl M.t polyvinyl chloride. Ann N.Y. Acid Sci 244:1175. 2. Manual d the International Classification of Diseases Adapted in (he Unled State*. Eighth Revision. Washington. D C. US. Cost P- - Office. 1967, Vol. 1. 3. National Center for Health Statistics: Vital Statistics el the l - - States. 194# - Volume II - Mortality. Part A. Washington. DC L-* i Printing Office. 1972. pp. 140-205. 4 Chtaue L.: Problems of study design and interpretation o> mo,.- mortality experience. /OM 18:169-170. 1976. S. Redmond CK and Brcsiin PP: Comparison of method* for asses. ciattonal hazards. (OM 17:313-317, 1975. . 6 Monson RR. Peters |M. and Johnson MN: Proportional mortaiil. j~ v.ny(-chloride workers, lancet 2:397-398. 1974. 7. Lloyd JW and Ciocco A: tong term mortality study of steels.TM.Methodology. IOM 11:299-110. 1969. 8 Redmond CK. Ciocco A. Lloyd |W. and Rush HW: long term m.f- study of steelworkers: IV. Mortality from malignant neoplasms i"x oxen workers. IOM 14:621-629. 1972. 9 Tabershaw IR and Caffey WE: Mortality study of workers * - manufacture of vinyl chloride and its polymers. (OM 16:509-518 :*'* (production The concept , means of up nJO's. the Amt toe* for the .jxtificate of re t^npliance. In HP of the lr tods to tncluc to several yeat toetest in the deds were stil occupational > hrgefy in the pcciate the r After sever, positional 1 -Health and Sa was imally est panted OHl -eew standard de staff ol l .s.Wtth then -OHSPAC anr wte. While > dustnal Hygt* be economu I charges to b j fcwnt to CO. teems. Some he accredits f the elfor Ahhough bnpended. kuerpteutK taxational t The docum oxeria for bHdical. N m Mortality Among Employees of PVC Fabricators/Chiazze. Nichols. Wcri Wnal of C 725018 r* &