Document MMjO12NeJjDkDw127kQN5rayk

1**1 70;.; 1u Jl' *+' .`t *n Foilowing this exploratory survey, the ihltlalefforl wa* dire clod to the collection of dele relating to all workere who had been processed through the clinic at Thetford Mince since lie Inception la 1947, and similar Informa tics regarding all workere at Asbcetot, P.Q. Data from-the clinical records included the age, family and personal medical bletorloa, smoking habits, number of years of exposure, an cellmate of weighted exposure, and the course of the individual's health status or the cause of his death. From this Information it was possible to formulate a "cohort" which could be well defined, should be representative of thg whole group, and could be followed for a deflnlto period of time. All of the available experience Indi cates that the development of aebostosis in loss than flvo years of oxposure must bo somewhat rare. Accordingly, the cohort was defined as Including srsry wosiaov who had a total exposure of five or more years, and who was on Offieetr*t* //* the employment rolls In lISO.^Thls cohort was then followed by means of tp h*V(/4'/slt7^ Wc<c */*' /yctv/r/- the annual physical'examination records through a six-year Interval, 1950 through 1955. All data regarding this group wero than tabulated la order to determine the cbaractorietico of the cohort. For thoee who survived the en tire period, reference wee made to the physical examination results snd x-rsy findings st the end of the period. Thoee who hed died wore tabulated separately sad the cause of doath corroborated by examination of the death certificates. A lurthor search was made concerning those la the. original cohort who re mained unaccounted for when the living and the known dead had been tabulated. They represent moo who had left employment through retirement or resigna tion. Eventually, all but a email number of thoee were accounted for as either