Document ZGx4aezaG8waZKOyMob4gMR0

CHEMICAL MANUFACTURERS ASSOCIATION July 31, 1980 To: Vinyl Chloride Research Coordinators The most recent EHA proposal for an update of the vinyl chloride mortality study (Final Report prepared by Equitable Environmental Health, January, 1978) is enclosed for your review. The proposal was developed after a series of discussions with EHA staff in Berkeley, California on June 25/,,A 1QQn --J-`-- *1'''-------- ference were: Dr. Ted Torkelson Mr. Nick Wheeler Dr. Maurice Johnson Dr. Chi-Pang Wen Dr. H. Michael Utidjian Dr. Carol Stack Mr. Joseph Seawell Dr. Thomas Milby Dr. Clark Cooper Mr. Richard Davis Dr. Donald Whorton Dr. Harrison Stubbs Ms. Jane Schulman EHA Consultant EHA Staff On the first meeting day, Mr. Richard Davis and Dr. Thomas Milby presented a detailed history of the existing study, described methodology used in data collection and analysis, and provided a summary description of the present condition of the data base. A condensation of their comments may be found on pages 1-3 of the Introduction and Background section of the proposal. Attached are additional materials distributed at the meeting that will provide you with further details on the composition of the co- hort. On the second day of meetings, several options were considered for a comprehensive update of mortality in the 10,173 member cohort. In considering various options, information gained was weighed against projected time and costs that would be expended by both EHA and the plants involved. In the original study, data were gathered from 34 plants representing 17 companies. The "Cohort by Type of Plant and Year Records Began" chart was carefully scrutinized and the merits of including all or combined segments of the cohort in the follow-up were discussed. For example, consideration was given to including all "prior to '59" exposures and excluding "after '60", or following up on only those with complete data in all categories. Ultimately, it was proposed that all 10,173 workers in the original cohort be included, although it is recognized that a small portion of these will be lost to follow-up by virtue of the fact that code numbers for some individuals can no longer be matched to names. CMA 009183 Formerly Manufacturing Chemists Association--Serving the Chemical Industry Since 1872. 1825 Connecticut Avenue. NW Washington, DC 20009 Telephone 202/328-4200 Telex 89617 ,'CMAWSH! VC Research Coordinators July 31, 1980 Page Two 1 Information required of the plants is described on pages 6 and 7 of the proposal. On page 3, the statement is made that exposure duration be terminated on December 31, 1972. At the meeting it was suggested that the plants consider: 1) updating work histories post 1972 ('72-'79), and 2) provide the same information on employees entering the work force with at least one cumulative year of vinyl chloride exposure post '72 through December 31, 1979. These options are still open and would not add appreciably to EHA's projected costs; however, they would place an additional burden on the plants. EHA considered that, given the substantial drop in worker exposure levels during the 1970's, information gained by including these options would not be worth the additional effort at this time. This data would be a valuable addition if future follow-up studies on this cohort were planned. Brain Tumors - Case-Control Study Dr. Whnrton briefed the group on what would be needed to conduct a proper casecontrol study using the twelve brain tumor deaths found in the earlier mortality study as "cases". (Reference to a preliminary review of eight of the cases is made on pages 11-12 of the proposal). In order to select a suitably matched group of exposed controls from the cohort, considerably more medical and occupational information would be needed than is presently available. Data of this nature may be obtained through several channels, including workers' compensation, health insurance records, questioning plant personnel and/or coworkers. Contacting the deceased's family for personal infor mation has become increasingly difficult due to the legal protection now afforded them, and gaining access to medical records is also a difficult task. If one were able to collect sufficient data on the 12 cases and a control group, the exposure duration factor would be compared. Dr. Whorton also noted that of the 12 brain tumors found, six were classified as primary astrocytomas, one as "other", and five were non-descriptive. It was Dr. Whorton's opinion that a case-control study performed at this time could not be conclusive and, therefore, little would be gained from it. However, if the follow-up reveals more brain tumor deaths, reconsideration should be given to a study of this type at that time. Those present were in agreement with this suggestion. This material will be used as a basis for discussion at our meeting on September 17, 1980. I look forward to meeting with you at this time. CRSimd Enclosure Carol Project Administrator Vinyl Chloride Research CMA 009184