Document jBro76d9DwaE5DLV0wnj47mrN

c o ri d rvruL Interim Report to the Quebec Asbestos Mining Association at Epidemiological Study of Lung Cancer is Aabestos Worker* Thi* interim report it presented to acquaint the Association with the progress Of the work thus for end the plans for the remains*r of the study. The'objective* of the program e* proposed in the memorandum of Mereh 16, 1956 were to determine: 1, Whether there i* relationship between esbestosts end lung cancer. 2, Whether a relationship may exist between mere exposure to asbestos and lung cancer. ' The suggested procedure included the following stepi; 1. An intre.industry study, selecting a group of people which entered the asbestos industry from ten to twenty years ago and following their future health status. 2. A comparison of this group with the general popu lation of the Province of Quebec er55 l. A comparison of th* group under study with the ' _ populations of eh* Donuntom o{ Canada and ol k the United State*. 1a tin* with these abjective* end suggested procedures, the initial effort was directed to the collection of data relating to all workers who bed been processed through the clinic at Thetford Mines, and of similar information on the worker* at Canadian Johns-Manviil* Company in Asbestos. Following the initial visit is February, 1956, the firstfield work was begun in July at theee two locations. Although the data in the two instances were net exactly similar inform, the inclusion of record* from the personnel department at Asbeeto* covering employee* who had retired, died, or become disabled provided data eufficicntly alike for the purposes of the study. Data from these clinical recorde included the age, family and personal medical histories, smoking habits, number of years of exposure, on estimate of weighted exposure, and eventual course of boalth statu* or cause of death. Death certificates in th* Province of Quebec for the years 1951 to 1955 inclusive were reviewed during the last week of July, This infor mation was obtained either from the death certificate* themselves or from XUM card* summarising the certificates, in th* Department of Vital Statistic* o( th* Provincial Health Ministry. All case* in which death wea certified a* having been due to lung cancer were examined for such information a* the 03Si 1. place of residence, occupation, dot* of death, hospital in which death occurred, end whether or not on autopsy was performed. Cite* in which lung concur * given t a ctute of dtath hut in which it was not tpeeified ne to whether tholung concur originated in the lung were nlto ttudied. In September, ndditionel detc on provincial deeth certificates were collected end the record* of the Sun Life Assurance Company of Cnnedn were examined in order to obtain information on death claim* paid under the group iaturnnee policy covering the Canadian Johns-Manvill* worker*. Statistic* for the Province of Quebec, relating to population, total deatha from all cauaet, total death* from cancer, and death* from lung cancer were collected and have been tabulated by countie* and by sex for the year* 1950 to 1955, Thee* data at* currently being processed in several different way*. Death rate* for th* general population in specific year* art being established. They will he classified according to total deaths, death* from cantor, and deaths from lung cancer by county of roeidenc* and by sex for the years 1950 to 1955 inclusive. They will then be analysed to determine which factor* seem to be rotated to any unusual incident* of lung cancer. Deaths from lung cancer among asbestos workers arc being determined from information contained in th* clinical records a* well as from lhe death certificate* and insurance record*. In order to verify th* figure*, the individual death* sre now being reviewed with th* phyticisns 0357 f 4. At Asbestos tad it Thetfcrd Mines, Tht unit verification will be carried'? out for th death certificate information. Cn completion of tbit phase, it will be^possible to cttiblitb i iitt of ease* in which primary cancer of the lung hit been proved it th ciuto of death. AH tho citot in which lung cancer it strongly suspected but unproved it the ctut* of death will b< listed separately. Beth litts will then be subjected to careful analysis to determine pottiblt rtlitieathipt or correlations between lung caneer end toy of the other factor* known from the clinical records, Such foctort tsay include family history of cancer) per tonal history of heavy smoking, etc. Any apparent ditertpanciet in the correlation! will be_carefully evaluated to avoir pottiblt bitt and to atture proper conclusion! from tht resulting statistics. The "cohorts" being established for the Thetford Mines group and ths Canadian Johns-Manviii* group will be used to make comparison of the health experience and the death rates of asbestos workers between these two groups and between them and the general population. The death rate from lung cancer among these workers can be established and compared with the death rate from the same cause among the general population and among specific segments of unexposed person*. After consideration of all factors affecting the comparability of the figures, the cohorts referred to arc being established by picking out all employees of record for a selected year. Those still working st this time will be subtracted from this list. Of the remainder, those who have died of all causes will be studied exhaustively. There will, of course, be a few who will have been lost to the record, but every attempt will be made to reduce inis number to an irreducible minimum. 0358 s. In. Addition to the Above, related bibliographical material has been collected, studied And abstracted. Particular emphasi* is being pieced ott the accumulation of relevant background statistic*. In summary, several available sources of data have been ex* amined to date. From these sources, information pertinent to th* problem has been collected and is being reduced to a form in whiea it can be con veniently analysed. Meanwhile, the literature is being searched with re lation to asbestosis and to statistics relating to the association between asbestos is and iung cancer. Respectfully submitted, March I. 1SS? 0359