Document n9z0gyZXb1DpN033BDpGzyvvG

Opinion on presentation by Ms. S. Selevan at the APHA Convention 20.10.75 entitled Mortalit anyd Environmental Assessment of Vermont Talc Mines and Mills It is always difficult to give an authorative opinion on the transcript of a paper presented verbally at a meeting Slight inaccuracies in transcription the impossibility of knowing what the speaker was pointing to when referring to slides and lack of details of methods criteria and findings contribtu o tthee difficulties Notwithstanding these problems I venture the following comments - Mortality from all and particular causes among 405 talc miners millers and miscellaneiusly exposed workers was compared with that for the State of Vermont as a whole and for the USA retrospectively It is not clear how many of the 405 were miners how many were millers or . how many were miscellaneously exposed _ Definition of probands 2.1 2.1 Those studied had to be employed for not less than 1 year all told and for not less than 1 day between lat January 1941 and 31st December 1969. Thus at one extreme it is possible that the 405 include men who started employment on 2nd January 1940 and left on 2nd January 1941 and men who started on 31st December 1969 and left on 31st December 1970. At the other extreme it could include men employed continuously from before 1940 until after 31st December 1975 3.2 It is not clear how the 405 probands were found nor what proportion of a larger population they represented If the 405 is the relic of a much larger number of individuals most of 0163494 JNJ 000036248 -- 7) whom were untraced then the study is of no validity for any - purpose It is difficult to believe that every oligible person employed as a miner or miller etc. from 1940 through 1970 was traced Almost certainly some were lost to follow The text at the middle suggests that follow was indeed of p.4 very of the transcript incomplete It is extremely important to know what proportion was traced 3.3 It is not at all clear what a mixture of miscellaneous category means 3.4 ~ No attempt seems to have been made to ascertain whether individuals had other relevant occupational history e.g. working in other types of mine or with other dusts More importantly there is completely inadequate information on smoking habits see below 3.5 It is no fault of the author of the paper but a defect nevertheless that there is no reliable information on exposure levels for the miners or mills until recent times 4 Calculation of expected death rates 4.1 The method used appears to have been unnecessarily crude it is possible to calculate expectation of death from specific causes accurately for a defined population using specific- , mortality data for each cohort Maybe this was done It is not clear 4.2 On p.3 lines 22 - 27 etc. of the transcript the author rofers to possible bias in calculating expected death rates for the population of Vermont In my opinion the likelihood of bias of the kind described renders the comparisons between the probands 0163495 JNJ 000036249 5 Causes of death of death were obtained I It is not clear how data on causes 5.1 that they are unverified death certificate have the impression data adequately established Of the 6 respiratory cancer deaths the of presence lung cancer death was not in my view in Daniel Guyett the interval between first Allen and Hale In two other cases was too short for it to be from lung cancer and employment to tale caused the cancer reasonably likely that exposure and was in known whether he was a smoker Only for two of the 6 . it is not known how much Guy tt smoked It is tract not clear whether cases were looked for and not of cancer of the found or whether upper respiratory they were not looked for 6 Results the study has revealed no it is clear to me that Whatever else On the other hand if risk of death from neoplasia excess finding in the millers even the negative follow was incomplete in this regard could be misleading millers and the mixed exposure group It is puzzling why the should have shown an excess of non- but not the miners disease emphysema 5 cases and pneumo- malignant respiratory ' Obviously one needs coniosis including silicosis 6 cases details and to have better information to know more exposure both before and after about other occupational expsoures mills and about smoking habits working in the talc mines or e 0163496 JNJ 000036250 7 Comments 7.1 This is obviously a totally inadequate study - but the extent ue cannot be determined without further inform- - of the inadequacy ation The data base is meagre and the data largely unreliable In these circumstances the speaker not only did a disservice to science by discussion presentinthge paper but points His conclusion made that quite inappropriate the present study clearly demonstrates malignant respiratory disease is to relatively pure tremolitic associated with exposure talc is not justified by the data 7.2 details of the study and to extend I should be glad to see more . or expand the above opinion in the light of them FJCR 14.4 me Pt eo ee we WH ' . 0163497 JNJ 000036251