Document RjvmkqE0eqE4jm65XvbMDzvdz

RECEIVEDH*yO^ IS3G URL 15824 Environmental Health Associates, Inc. 26 August 1980 Carol Stack, Ph.D. Chemical Manufacturers Association 1825 Connecticut Avenue, N.W. Washington, D.C. 20009 Dear Carol: This is in response to your telephone inquiry concerning the number of deaths we would expect to be generated by the pro posed follow-up mortality study. A precise estimate is not possible since we do not have the person-years-of-obs^rvation tables from the 1978 report available to us. Using the person years tables from the 1974 report, we can estimate that an additional 350 to 400 deaths would be generated by the follow up. This is a conservative estimate since the portion of the cohort added after 1974 was made up of older individuals. This estimate was generated on the assumption that we will be able to ascertain the vital status of the 9,677 individuals used in the 1978 analysis and that similar mortality patterns prevail. The addition of 350 deaths would generate sufficiently large numbers of observed deaths to provide statistical significance in those categories with excessive SMRs in the 1978 report. Any change in the mortality patterns as a result of the addi tional years of observation would alter the SMRs. For instance, if we failed to detect six additional brain cancer deaths, the 1978 SMR of 203 would be lower. If an additional six were detected, the number would be large enough to generate a statis tically significant SMR of 203. This latter is an example of one of the advantages the follow-up will provide. If you need additional information, please give me a call. Sincerely yours, RLD:nm cc: T.R. Torkelson Richard L. Davis Director, Health Management Services 2150 Shattuck Ave. Suite 414 Berkeley, CA 94704 (415) 548-1888 * Cable: ENV1RO