Document bBkVoQ2rKk99nO6v6ydVvYqpg

216 WILLIAM V. LORIMER T AL The relationship between pulmonary function signs of restriction and abnormal x-rays was investigated. No significant association was found (Table X). Chest x-*ay: The chest x-rays were read twice by consensus reading, using at least three experienced readers, and categorized according to the 1LO/U/C classification. An x-ray was read as abnormal if fine or moderately thin, irregular linear opacities were present (s or t > 1/0) and/or pleural thickening was present (a-1 or more). The prevalence of abnormal readings is given in Table XI. Parenchymal abnormalities were present in 19 instances, nine 1/0, six 1/1, two 1/2 and two 2/2. X-ray findings consistent with asbestosis increased with time; such a trend is evident in Table XII. This trend is statistically significant. TABLE X Relationship between X-Ray Reading and i'ulmonary Function Tests in 87 Vehicular Maintenance Workers Pulmonary function Number of Subjects X-ray reading Percent Restriction Obstruction Normal 25 Abnormal* 5 20% Normal 20 80% 43 Abnormal* 15 35% Normal 28 65% 30 Abnormal* 8 27% Normal 22 73% * parenchymal fibrosis Slid/or pleural thickening For overall pa (.tern X' - 1.78 .50 > p > .30 For restriction alone X* - 1.21 .30 > p > .20 For obstruction alone X' - 1.60 .30 > p > .20 For obstruction and restriction compared to normal: X1 - .08 .80 > p > .70 TABLE XI X-Ray Changes in 90 Vehicular Maintenance Workers with over 10 Years' Experience Number Percent Parenchvmal fibrosis Pleural thickening or calcification Both parenchymal and pleural chances Any changes 18 20% 5 6% I 1% 24 27% TABLE XII X-Ray of Vehicular Maintenance Workers by I'rsr of Onset of Work Abnormal* 1956-65 1946-55 Before 1946 Yes No Yes No Yes 3 14 10 33 14 (18%) (23%) (47%) No 16 * Parenchymal Fibrosis (1LO/UC a, t > I/O) and/or pleural thickening X' for before 1956 compared with 1956 and alter: X' - 5.95 .02 > p > .01 *