Document n1gm1qyvD0aO5D668KnM6xp1

As there was some time lapse between the statistical planning and the field survey, by the time of the first working expedition to the plant in August, 1968, some of the original selection had been lost, chiefly by resignations and drafting for military service. There had also been one death from causes other than pulmonary disease. Lastly, although alto gether three field trips were made to the plant in August, September and October, a further number of selected employees was not accessible by reason of vacations and current sickness. Finally 232 of the originally possible sample of 261 were investigated, and their distribution among the "cells" is shown in the third part of Table I. Note, however, that the greatest deficit is in the youngest age group and that the highest ex posure/oldest "cell" is intact with the full thirty. An investigation was made of the reasons for non-availability of employees, and as in no case was the absence found to be due to illness referable to the respiratory system, it was decided to proceed with this reduced sample rather than incur the possible statistical bias introduced by substitution. THE QUESTIONNAIRE All 232 employees examined were subjected to a questionnaire, blank copies of which have been circulated among you. This is based upon a modification of the British Medical Research Council "Bronchitis" questionnaire, now in use in a major study of Canadian asbestos miners. Sections 1 and 2 were completed by the personnel and medical departments from company records, and section 3 by the work super visor. All parts of Section 4 were administered at interview conducted by two IHF staff physicians assisted by Dr. J. Konzen, Owens-Corning Fiberglas, Corporate Medical Director, to whom none of the employees nor their medical histories were previously known. The appraisal and scoring of all the completed questionnaires and the organization of the data into tables acceptable to the biostatisticians, was performed by one of the three physicians involved in the interviewing. Following completion of the questionnaire each employee was weighed and his height measured by the plant nursing staff and spirometry was then performed by Dr. Ben Lambiotte of the Foundation's staff (who will be speaking later in the program), using a standard Collins' type spirometer. Two acceptable forced expiration tracings were obtained from each subject. While it will be possible later to calculate the F.E. V.i. q and Maximum Mid-expiratory Flow Rates from these tracings, at this time only the total vital capacity (untimed) will be presented. Lastly, the chests of all subjects had been X-rayed recently by well trained technicians in the plant clinic, and the films read by fully qualified radiologists in the community. Drs. Konzen and deTreville re viewed these 14 x 17 films, and Dr. Konzen will discuss the radiological findings later in the program. I shall largely confine myself to the re sults of the questionnaire and will refer only very briefly to the results of spirometry and radiography. 0. 33 J! V9 . i