Document BRngzxxVmgQR4kL66KnY1YVak

REPORT ON A CASE CONTROL STUDY COVERING WHITE FEMALE EMPLOYEES OF PVC FABRICATORS May 1977 2587001 Counselors, Inc. C/t-' > L , v' J c. it >'--* /. BFG21822 CONTENTS Page BACKGROUND ........................................................................................ 1 DEVELOPMENTS IN THE SCIENTIFIC LITERATURE.......................................................... 3 ORGANIZATION OF THE STUDY................................................. Data Collection................................................................................... Data Interpretation.............................................................................. 4 5 5 DESCRIPTION OF PARTICIPATING FABRICATORS................................................................................... Geographic Distribution of Breast Cancer Deaths . . . Sex and Ethnic Mix............................................................................... Turnover Rate........................................................................................ Extent of Unionization.......................................................................... Use of PVC Resins............................................................................... 5 6 7 7 7 JOB CONTENT AND EXPOSURE POSSIBILITIES.... 8 MONITORING HISTORY..................................................................... 10 THE CONTROL GROUP..................................................................... 11 FIELD WORK........................................................................................ 11 STATISTICAL PROCEDURES...................................................... 12 INTERPRETATION OF RESULTS............................................ 15 OBSERVATIONS................................................................................... Recordkeeping........................................................................................ Exposure Records............................................................................... Conflict with other Regulations........................ Errors in Work Force Estimation............................................ 16 16 16 17 17 to O L S S Z Z BFG21823 ORGANIZATION RESOURCES COUNSELORS, INC., 1270 AVENUE OF THE AMERICAS, NEW YORK, N. Y. 10020 \ j Contents (continued) Table 1 2 3 4 5 6 7 8 9 Distribution of Deaths Attributed to Breast Cancer Among Eight PVC Fabricators by Company, 1964-1973 (White Females Only) Observed and Expected Deaths Due to Selected Causes Among Employees of 17 PVC Fabricators, 1964-1973 Maltoni Experiment BI 15 (October 1976) Exposure for 52 Weeks, 4 Hours/Day, 5 Days/Week for 1 Year; Results After 87 Weeks--Sprague-Dowley Rats Distribution of 35 Cases and 134 Matched Controls by Exposure Category Distribution by Company of 35 Cases and 134 Matched Controls Available for Analysis Average Years Employed for Cases and Controls With Known Length of Employment Distribution of Cases and Controls by Continuous or Intermittent Employment Distribution of Cases and Controls by Marital Status Distribution of Cases and Controls by Child bearing History Page 18 19 20 21 21 22 22 23 23 22587003 BFG21824 ORGANIZATION RESOURCES COUNSELORS, INC.. 1270 AVENUE OF THE AMERICAS. NEW YORK, N. Y. 10020 BACKGROUND In January 1974, B. F. Goodrich Chemical Company dis closed that angiosarcoma of the liver was the cause of death of three employees at that company's Louisville, Kentucky plant. The Good rich disclosure suggested the possibility of a new occupational disease and showed a need to reevaluate the standard of the Occupational Safety and Health Administration (OSHA) for occupational exposure to vinyl chloride. At that time, there were no data from which to determine the prevalence of angiosarcoma of the liver in the plastics industry. On further investigation other cases of the disease were found in the industry, but the pattern of occurrence suggested that they were as sociated with those processes which involved high concentration of vinyl chloride monomer which had not been converted in the polymeri zation process. Thus, there was a question of whether adverse effects were possible for employees who had been engaged in fabrication in situations where potential exposures were thought to be low and to result only from the release of unreacted monomer trapped in the resin. Representatives of the PVC producers who were members of the ORC Occupational Safety and Health Standards Group questioned Leo Teplow, Special Consultant to ORC, on the feasibility of a study of the health risks to employees who were working with vinyl chloride and polyvinyl chloride. When it was learned that the National Institute BFG21825 ORGANIZATION RESOURCES COUNSELORS, INC., 1270 AVENUE OF THE AMERICAS, NEW YORK, N. Y. 10020 22587004 2 for Occupational Safety and Health (NIOSH) was engaged in conducting a mortality study of employees in vinyl chloride and resin producing plants, the scope of the proposed study was limited so that it included only em ployees engaged in the fabrication of finished products, using PVC resins. The objective of the study would be to determine the facts and cause in volved in the deaths of employees in 17 PVC fabricators in the period from 1964-1973. Of specific interest would be whether any case of angio sarcoma of the liver had occurred, such information to be based on an analysis of death certificates. Once these figures were extracted and the distribution of causes determined, they were to be compared with pub lished mortality tables. Industry decided that such a study had merit and agreed to finance it. ORC then contacted Dr. Leonard Chiazze, Director of the Division of Biostatistics and Epidemiology, Department of Community Medicine and International Health of Georgetown University, who de signed the protocol, developed a records system, and interpreted the results. The ORC staff served as the interface with industry, and was responsible for field work. ORC issued "Report on a Mortality Study Covering Employees of PVC Fabricators" in February 1976, and at the time copies were submitted to OSHA and NIOSH. On June 16, 1976, there was a discussion of the findings among representatives of OSHA, NIOSH, Dr. Chiazze, participating companies, and ORC. ------------------------------------------------------- BFG21826 ~ ORGANIZATION RESOURCES COUNSELORS, INC., 1270 AVENUE OF THE AMERICAS, NEW YORK, N. Y. 10020 2587005 3 ) The ORC study identified 44 deaths among white women in which the underlying cause of death was cancer of the breast. The 44 deaths attributed to cancer of the breast occurred among women who were employees of eight of the participating companies (Table 1). On the basis of a Proportional Mortality Ratio analysis, the number of deaths due to breast cancer appeared to be somewhat greater than had been anticipated, with the expected number being based upon the distribution of deaths, by cause, among all U. S. white women. The study did not reveal any case of angiosarcoma of the liver among employees of the fabricators under study. There were, however, some possible excesses identified in the Proportionate Mor tality Ratio analysis, and these are summarized in Table 2. The ) finings also indicated that there was a need to do further research to determine the feasibility of analyzing work histories. During the fall of 1976 there were discussions of alternative follow-up studies. DEVELOPMENTS IN THE SCIENTIFIC LITERATURE Concurrent with discussions concerning a follow-up study. Dr. Cesare Maltoni, whose research in Italy played an important role in the development of the OSHA Standard for Occupational Exposure to Vinyl Chloride, released interim results of a study on rats exposed to low levels of vinyl chloride monomer. His preliminary findings. ) BFG21827 ORGANIZATION RESOURCES COUNSELORS. INC., 1270 AVENUE OF THE AMERICAS, NEW YORK, N. Y. 10020 22587006 4 ) shown in Table 3, suggested the possibility of a dose response rela tionship at low levels of exposure between vinyl chloride and mammary tumors. In an NIH Symposium in January 1977, Dr. Joseph Wagoner of NIOSH commented on the Maltoni results (Table 3) and the Chiazze/ ORC results (Table 2). The implications of the two studies were obvious. Exposure to vinyl chloride--whether as a result of direct inhalation of the monomer under controlled conditions or as a result of the occa sional release of unreacted monomer entrapped in the resin--might induce tumors. In December 1976, Dr. Chiazze and ORC recommended that a case control study be conducted to determine the work histories ) of the white female employees in the study whose death certificates indicated breast cancer as the underlying cause of death. Only white females were studied, as no breast cancer deaths were found among males in the original study and the number of nonwhite females (23 deaths from all causes) was too small for further analysis. ORGANIZATION OF THE STUDY After a discussion of the merits of a follow-up study, the eight companies decided to proceed with a case control study and agreed to finance it. ) ~ BFG21828 ORGANIZATION RESOURCES COUNSELORS, INC., 1270 AVENUE OF THE AMERICAS, NEW YORK, N. Y. 10020 22587007 5 Data Collection William E. Nichols, Ph. D., and ORC Consultant, was re sponsible for the design of the questionnaire used to elicit work histo ries and for auditing for accuracy the personal data entries on the death certificates. He also scheduled the necessary plant visits and super vised the data collection team. The plant visits were made by William E, Nichols; G. John Tysse, ORC Consultant; Carolyn Sutherland, ORC Staff Associate; and Maha Shakhashiri, Georgetown University, Re search Associate. The field work was conducted between February 25 and March 28, 1977. Data Interpretation Leonard Chiazze, Sc.D., Associate Professor and Director, Division of Biostatistics and Epidemiology, Georgetown University School of Medicine, was responsible for designing the protocol, veri fying the field reports, providing for data processing, and interpreting the results. DESCRIPTION OF PARTICIPATING FABRICATORS Geographic Distribution of Breast Cancer Deaths The 44 breast cancer cases occurred in 19 locations of eight of the 17 companies that were included in the original study. Twelve locations with 23 of the deaths were in the East, and seven locations with 21 of the deaths were in the Midwest. It is interesting W 800L8G Z -------------------------------------------------------------------- BFG21829 ORGANIZATION RESOURCES COUNSELORS, INC., 1270 AVENUE OF THE AMERICAS, NEW YORK, N. Y. 10020 6 to note that 40 of the 44 decedents worked in plants north of the Ohio River and east of the Mississippi River, where there is a deficiency of selenium in the soil. ^ Three of the 44 breast cancer deaths occurred in offices physically located in separate cities but treated administratively as a part of plant employment. Another eight deaths occurred in a general office located in the same city as a major plant. The remaining 33 deaths occurred in plants that ranged in size from 300 to 7, 000 employees. Sex and Ethnic Mix Work populations in the 19 locations reported in this study were predominantly male during the study period 1964-1973 and seem to be con sistent with the ratio of deaths (85. 4 percent male) found in the analysis of death certificates on which the original study was based. There has been an increase in female employment in recent years, and the ratio for the study period years is not representative of current employment. Similarly, the ethnic mix in the 1 9 locations during the study period was predominantly white (88. 3 of the deaths in the orginal study were known to be white). All but two of the plants reported that 1 See "Studies Firm Up Some Metals' Role in Cancer, " Chemical and Engineering News (January 17, 1977), pp. 35-37; Birger Jans son et al., "Gastrointestinal Cancer: Its Geographic Distribution and Correlation to Breast Cancer, 11 Cancer (December 1975), p.2373. M ^ 3 Oc 40 BFG21830 ORGANIZATION RESOURCES COUNSELORS, INC., 1270 AVENUE OF THE AMERICAS. NEW YORK, N. Y. 10020 7 ) nonwhite employment has been increasing. The two exceptions are located in isolated communities in the Midwest where the nonwhite population is small. Turnover Rate Most of the plants report an overall low turnover rate because the wage levels in these companies tend to be higher than for other employers in the area, and because the work is relatively light. Turnover appears to be lower in rural areas than in urban areas, and lower in small plants than in large. The turnover that does occur is predominately among short-service employees. Extent of Unionization \ j All but two of the plants are organized, and a variety of unions, both independent and with international affiliation, are repre sented. Use of PVC Re8ins Histories of use of PVC varied widely among the plants, and at the time of the study period varied from over 20 years to less than five. Moreover, the form in which PVC was a raw material ranged from resins delivered in bulk by railroad cars to a raw ma terial that was considered a fabricated product as defined by OSHA N CTOL B ^ Z > ______________________________________ ORGANIZATION RESOURCES COUNSELORS, INC., 1270 AVENUE OF THE AMERICAS. NEW YORK, N. Y. 10020 8 and was extruded at the plant. An example of intermediate state includes pellets with color added by the PVC resin producers. JOB CONTENT AND EXPOSURE POSSIBILITIES A multitude of jobs were held by the breast cancer cases, ranging from office and clerical worker (10) and outside salesperson (1) to production jobs such as bench inspector, press operator, trimmer, assembler, and sweeper. Such a wide range of job content and location made it impossible to determine precisely whether there was PVC exposure in every case. Therefore, it was necessary to develop a subjective ranking system. McMichael et al. developed a system of Occupational Titles in which jobs in the rubber industry were grouped together on the basis of operation (type of machine and/or process) and materials handled. Their study was in a homogeneous industry with emphasis on tires, tubes, flaps, and bladders. However, in the ORC study 2 "Fabricated product" means a product which is made wholly or partly from polyvinyl chloride, and which does not require further processing at temperatures, and for times, sufficient to cause mass melting of the polyvinyl chloride resulting in the release of vinyl chloride (29 CFR 1910.1011(a)(6)). 3 A. J. McMichael, M.D., Ph.D; R. Spirtas, Dr. P.H. ; J. F. Gamble, Ph.D. ; and P. M. Tousey, B.S.N. , "Mortality Among Rubber Workers: Relationship to Specific Jobs," Journal of Occupational Medicine (March 1976). N ! BFG21832 ORGANIZATION RESOURCES COUNSELORS, INC., 1270 AVENUE OF THE AMERICAS, NEW YORK. N. Y. 10020 TT048SZ 9 there was insufficient compatibility of job tasks, machinery, material, and products to permit the use of such a sophisticated format. B. F. Goodrich Chemical Company developed a subjective rating scale for jobs at the Louisville, Kentucky plant as a part of its continuing study of health hazards in the polymerization stage. The exposure to chemicals (including vinyl chloride) in the Louisville plant was classified into six stages ranging from "no exposure" to "intimate contact--skin or high inhalation. " The rating program spanned approx- 4 imately seven months. Consequently, for purposes of this study, PVC exposure potential was categorized into five classes--"no exposure," "improb able exposure, " "possible exposure, " "definite exposure, " and "un known exposure"--as shown below. The distribution of cases and con trols by these categories is given in Table 4. Below, in tabular form, is a presentation of the various categories of exposure potential through employment, and examples of each. Classification of Exposure Potential Examples No exposure Employment terminated before PVC use PVC processed in a separate building from decedents' work station 4 Paige E. Mosser, "Industrial Data Bank-Work and Exposure Data, " paper delivered at University of Louisville Seminar on Medical Sur veillance in an Industrial Setting, April 21, 1977. 22587012 BFG21833 ORGANIZATION RESOURCES COUNSELORS, INC., 1270 AVENUE OF THE AMERICAS, NEW YORK. N. Y. 10020 10 >* Classification of Exposure Potential (continued) Examples (continued) PVC processed in the same building but removed from decedents' work station Improbable Decedent handled only fabricated products Possible Work station in vicinity of PVC resins; periods of no monitoring or with no detectable level of VCM. Definite Unknown ) MONITORING HISTORY Direct work with PVC resins Monitoring indicated a detectable level of VCM Employment records not complete enough to determine potential for exposure There was little history of monitoring among fabricators prior to the Goodrich disclosure, as VCM levels were well below the TLV of 500 ppm which was established by ACGIH and adopted in May 1971 by OSHA in its initial package of health standards. Following the Goodrich disclosure, and the subsequent development by OSHA first of an emergency temporary standard and ultimately of a permanent standard, monitoring was carried out, and the levels of exposure at jobs classified as "improbable," "possible," and "definite" and pre viously occupied by decedents, are well below the permissible levels promulgated by OSHA; in fact, almost all show no detectable level. 22587013 BFG21834 ORGANIZATION RESOURCES COUNSELORS, INC., 1270 AVENUE OF THE AMERICAS, NEW YORK, N. Y. 10020 11 THE CONTROL GROUP A series of controls was used which matched for ages (plus or minus five years) and company of employment (plant, if possible). Eligible to be used as members of the control group were employees whose deaths were from diseases of the circulatory system (ICDA 390-458, Eighth Revision) and accidents (ICDA-E800-E999). Unfor tunately, not every breast cancer death had at least one matching con trol, and it was necessary to exclude nine deaths from analysis, leaving 35 deaths with matched controls. FIELD WORK In planning the field work, emphasis was placed on obtaining ) employment histories on the 35 cases with matched Controls. However, it was also possible to obtain such information on five of the nine un matched cases, and the information suggested that their exposure his tories were generally similar to the 35 matched cases. The exposure information on the nine deaths excluded from further analysis is sum marized as follows: -- 4 deaths with no information (010052, 010256, 010279, 120382) -- 5 deaths with some exposure information (020001, 030006, 060094, 070281, 080019): -- 2 deaths with no PVC exposure, - 2 deaths with PVC exposure improbable, N -- 1 death with no record of the individual having worked in the plant. Possibly employed in a retail outlet. ) o H- BFG21835 ORGANIZATION RESOURCES COUNSELORS, INC., 1270 AVENUE OF THE AMERICAS, NEW YORK, N. Y. 10020 Table 5 presents the distribution by company of the 35 breast cancer deaths (hereafter called cases) and the 134 controls matched for age which were available for analysis. Mean age at death of the cases and controls was compared as a check on the matching procedure. Average age at death for the 35 deaths attributed to breast cancer was 62.6 (standard error = 2. 26) compared with an average of 65.0 (standard error = 0. 99) for the controls. Although controls are slightly older on the average, the difference is not significant when the standard errors are taken into account. Comparison of cases and controls using a variety of other variables---including length of employment, continuous vs. inter mittent employment, ever married vs. never married, and childbearing ) history--reveals no significant differences between cases and controls for any of these variables (Table 6-9). STATISTICAL PROCEDURES After matching by age and company, 31 matched sets of cases and controls were developed from the 35 cases and 134 controls. There are fewer matched sets than cases because, in four instances, there were two cases of similar age. The Mantel-Haenszel procedure was used to derive a measure of relative risk and to test for significant departures from unity. In this procedure, each of the 31 sets can be viewed as a 2 x 2 contingency table, as follows: ) BFG21836 ORGANIZATION RESOURCES COUNSELORS, INC.. 1270 AVENUE OF THE AMERICAS, NEW YORK, N. Y. 10020 13 ) Cases Controls TOTAL PVC EXPOSURE YES NO TOTAL A.i B.i Nii C.i 0. N2,.i Ma. T,l The relative risk is the ratio of the probability of developing the disease among women with PVC exposure to the probability among women not exposed, and is calculated as: A, 0, R T.1 z. Bl Cl ) iT To assess whether an observed relative risk may have occurred by chance, a Chi-Square test is performed. As detailed by Mantel and Haenszel, a summary one degree of freedom ChiSquare corrected for continuity is computed by the formula: (|pi. - Zj-(A,)| - H)Z XM2H ?V(A.) 9TC&8SZ2 BFG21837 ORGANIZATION RESOURCES COUNSELORS, INC., 1270 AVENUE OF THE AMERICAS, NEW YORK, N. Y. 10020 14 The calculated Chi-Square must be 3.84 or larger in order to conclude with 95 percent assurance that the observed relative risk did not occur by chance alone. Combining the five exposure categories into two may be accomplished in a variety of ways resulting in several possible relative risk measures. For example: 1. YES Yes only NO No only (ignore improoable, possible, unknown) R * 1.87 XMH " *0298 ) 2. YES Yes + improbable + possible + unknown NO No R - 0.5541 xJH - *0049 3. YES - Yes + possible NO * No + improbable + unknown R- 0.337 xAh B02,7 k. For Cases: YES = Yes + possible + unknown NO No + improbable For Controls: YES = Yes + possible NO * No + improbable + unknown R- 5-1065 xJh =1-8871 BFG21838 ORGANIZATION RESOURCES COUNSELORS, INC., 1270 AVENUE OF THE AMERICAS, NEW YORK, N. Y. 10020 *0 $ CD 3 H- 15 Note that in example 4, unknowns are treated as YES for cases and as NO for controls. This represents an extreme although highly unlikely possibility. None of the above calculated relative risks, including example 4, are statistically significant; that is, they may have occurred by chance alone. Similar analyses were carried out on a company-bycompany basis. None of the relative risks so calculated is significantly different from unity. Furthermore, the absolute magnitude of the highest relative risk achieved for any company in the most extreme case (example 4) was 1.75 (Xj^ = 0.498). INTERPRETATION OF RESULTS ) A great deal of caution must be exercised in the interpre tation of these relative risks. While they do not prove that there is no excess risk of death from breast cancer among women employees with PVC exposure, they do suggest that no overwhelming excess risk exists. On the other hand, considering that the proportion of controls which was exposed, or was possibly exposed, was 7. 5 percent, it would have been necessary to have more than 200 cases and 200 controls in order to detect a substantially large increase in risk, twofold, for example, with 95 percent assurance that a risk of such magnitude, if observed, did not occur by chance, and 80 percent probability of observing a cn oo -4 twofold risk if, in fact, it did exist. In order to achieve 90 percent O ; H0D ___________ BFG21839 ORGANIZATION RESOURCES COUNSELORS, INC., 1270 AVENUE OF THE AMERICAS, NEW YORK, N. Y. 10020 16 probability of detecting a true twofold r^sk, it would be necessary to have available about 400 cases and 400 controls. Given the percentage of controls in this study with PVC exposure (7. 5 percent), a percentage which was unknown at the beginning of the study, it would not be possible to detect small increases in relative risk. However, it is clear that no overwhelming excess risk does exist. It is likely that if an excess risk does exist, it is relatively small. Perhaps of greater importance, and based upon these data, is the suggestion that the proportion of women employees in these companies who had a history of PVC ex posure is substantially smaller than had been anticipated. OBSERVATIONS Recordkeeping The records of the participating companies were sufficiently complete in most cases to permit classification into the subjective cat egories. If one devotes sufficient time, it is possible to reconstruct reasonably complete work histories. Exposure Records Because of the TLV level for vinyl chloride prior to the Goodrich disclosure, it is impossible to estimate either duration or ., level of exposures on those jobs where decedents had the potential for direct contact with PVC resins. Similar studies in the future, whether - ^JG w on vinyl chloride or other substances, may encounter the same difficulty i __________________________ ORGANIZATION RESOURCES COUNSELORS, INC,, 1270 AVENUE OF THE AMERICAS, NEW YORK, N. Y. 10020 17 ) for pre-OSHA years. The less harmful the substance was considered, the greater the difficulty will be in determining exposures. Conflict with other Regulations Compliance with EEO regulations regarding entries denoting race, national origin, place of birth, or preexisting conditions may hamper legitimate epidemiological research in the future. Old em ployment applications and personal records contain entries that aid in current research, but are prohibited in today's records. Both sex mix and ethnic mix in the work force are changing drastically, and the researcher in the future must be sensitive to the shifting patterns in the work population under study. Errors in Work Force Estimation Estimates of the number of employees engaged in PVC fabrication and the percentage of employees with direct exposure to PVC resins seem to have been overestimated by both OSHA and em ployers during the deliberations that led to the OSHA permanent standard for occupational exposures to vinyl chloride. 0ZQISSZZ ----------------------------------------------------------------------- BFG21841 ORGANIZATION RESOURCES COUNSELORS, INC., 1270 AVENUE OF THE AMERICAS, NEW YORK, N. Y. 10020 1 Table 1 Distribution of Deaths Attributed to Breast Cancer Among Eight PVC Fabricators by Company, 1964 - 1973 (White Females Only) Company 01 02 03 06 07 08 10 12 Total Number of Deaths 14 1 1 16 4 3 4 1 44 18 XZ0L8SZZ ; BFG21842 ORGANIZATION RESOURCES COUNSELORS, INC., 1270 AVENUE OF THE AMERICAS, NEW YORK, N. Y. 10020 19 ) Table 2 Observed and Expected Deaths Due to Selected Causes Among Employees of 17* PVC Fabricators, 196A-1973 Cause of Death Observed WHITE HALE ALL CANCERS SELECTED TYPES OF CANCER Buccal Cavity and Pharynx Digestive (Including Liver) Liver Respiratory Breast Genitals Urinary Lymphatic (including Leukemtji) Leukemia 665 15 210 8 205 , 62 36 61 10 DIABETES 63. DISEASES OF CIRCULATORY SYSTEM 1,933 CIRRHOSIS OF LIVER 62 Expected 562.816 16.898 162.373 4.192 176.899 . 57-981 33.178 55.837 23.402 69.676 1,835.266 62.967 PMR* 1.18 0.89 1.29 1.43 1.16 ,, 0.72 1.09 1.09 0.81 0.87 1.05 0.67 WHITE FEMALE ALL CANCERS SELECTED TYPES OF CANCER Buccal Cavity and Pharynx Digestive (including Liver) Liver Respiratory Breast Genitals Urinary Lymphatic (Including Leukemia) Leukemia 179 3 53 a. 12 66 19 11 10 J DIABETES 10 DISEASES OF CIRCULATORY SYSTEM 277 CIRRHOSIS OF LIVER 3 135.933 1.872 36.929 0.827 11.715 31.907 22.971 6.687 12.681 4.9S1 15.276 305.578 12.136 1.32 1.60 1.52 ,. 1.02 1.38 0.83 2.65 0.80 0.20 0.65 0.91 0.25 PMR ratio of Observed to Expected where the expected number Is calculated on the basis of the I968 U.S. white male (or fe male) distribution of deaths specific for cause and age. ZZ0L8GZZ a Pate submitted by one company were excluded because it was not possible to identify cause of death. BFG21843 ORGANIZATION RESOURCES COUNSELORS, INC., 1270 AVENUE OF THE AMERICAS, NEW YORK, N. Y. 10020 1_ 0) JZ in cm 20 >rQo-) u Lia ^ MO- 10 CC vO j* >- or -- <u <D --a) ~3 1^ 3o 4) iA Q -O >* 1 OU O(0 43) O 7) o^ m lid. * Q_ i*n- >ID*</> I _Q 03 C<CvOM OzIu3AO.X(aA)> E3 -- -3" l. ,, r*- 4Q). -IXA OO X tu 34a>) *- -M) ... M- CO CinM < (A --to 1o-- s: <+- 3 U0) OI0CA) 3 (OA CL X 4. ou U 0) 4) -qE 3 Z IED J= o Ui_ ID IA o o <c -3-3" (D oi Eo U -M X <n CL ID 4) -- z .a e(o5 race -O ID -- --E --0 O4 M <D O o > in -3- i--n cvxm> -<3T-\ <y\ -3* viCOnM 030 Jue03) 3 CO cod) aa ooc oCM CoM oCM oCS oCM in cm o*- LA -- o Moo> (0MD w tO U1 3 ----------- ---------------------------------" BFG21844 ORGANIZATION RESOURCES COUNSELORS. INC., 1270 AVENUE OF THE AMERICAS, NEW YORK, N. Y. 10020 21 ) Table 4 Distribution of 35 Cases and 134 Matched Controls By Exposure Category Exposure Category Definite exposure No exposure Improbable exposure Possible exposure Unknown exposure Total Cases Number Percent 2 5-7 25 71.4 4 11 .4 4 11.4 Controls Number Percent 6 4.5 97 72.4 17 12.6 4 3.0 10 7-5 35 100.0 134 100.0 ) Table 5 Distribution by Company of 35 Cases and 13^ Matched Controls Available for Analysis Company Cases Controls 01 11 37 02 03 06 15 07 3 08 2 10 4 65 2 4 26 12 ) Total 35 134 BFG21845 ORGANIZATION RESOURCES COUNSELORS, INC., ]?70 AVENUE OE THE AMERICAS, NEW YORK, N. Y. 10020 &ZQL25ZZ Table 6 Average Years Employed for Cases and Controls With Known Length of Employment Study Group Cases Controls Number 31 117 Years Employed Averaqe Standard Error 26.53 2.37 25.60 1.08 22 Table 7 3 Distribution of Cases and Controls by Continuous or Intermittent Employment Type of Employment Continuous Intermittent Unknown Total Cases Number Percent 13 37.1 9 25-7 13 37.1 Controls Number Percent 31 23-1 32 23-9 71 53.0 35 100.0 13* 100.0 3 BFG21846 ORGANIZATION RESOURCES COUNSELORS, INC,, 1?70 AVENUE OF THE AMERICAS, NEW YORK, N. Y. 10020 Table 8 Distribution of Cases and Controls by Marital Status 23 Marital Status Ever married Never married Total Cases Number Percent 25 71.1* 10 28.6 Controls Number Percent 110 82.1 24 17.9 35 100.0 434 100.0 Table 9 Distribution of Cases and Controls by Childbearing History Children Yes No Unknown Total Cases Number Percent 11 31-4 k 11.4 20 57-1 Controls Number Percent 64 47.8 6 4.5 64 47.8 35 100.0 134 100. ) BFG21847 ORGANIZATION RESOURCES COUNSELORS, INC., 1270 AVENUE OF THE AMERICAS, NEW YORK, N. Y. 10020 ft & 00 0 It