Abstract
Among foundrymen, silicosis with small round opacities has been traditionally described for chest x-ray findings. Irregular small opacities have not been evaluated among foundrymen, even though they were implicated to result from dust exposures among miners. In this study, chest x-ray finding among foundrymen was examined together with lung function status. The study was conducted in a steel roll manufacturing foundry. 129 (70%) out of total 183 eligible workers participated in the survey which consisted of a self-administered questionnaire, spirometry, chest x-ray, and environmental measurements. There were no differences between participants and non-participants in age, tenure, sex and race. The average tenure of participants was 17 years, ranging 0.6 to 39 years. Chest x-ray was taken on 127 workers and read by three independent B-readers using 1980 ILO classification. Spirometry was done by 128 workers according to 1987 ATS Guidelines. Smoking status and pack-years of smoking was determined from the questionnaire together with other respiratory health risk factors including past work histories. Among the 127 chest x-ray films, 7 films were read to have reticulo-nodular changes by 2 or more B-readers, while 3 films were read positively by all 3 readers. Irregular opacities were reported in 6 out of 7 films by 2 or more B-readers, while 3 films were read to have round opacities by 2 or more B-readers. Stepwise logistic regression analysis was done to examine the occurrence of irregular small opacities in association with risk factors including age, tenure, exposure level to silica dust and SO2 gas, smoking status, and pack-years. Only job tenure was significantly associated with x-ray changes and others including smoking were not significant. The 95 percentile lower limit of normal values for lung function test from Knudson et al.'s data (ARRD 127:725, 1983) were applied to determine abnormal lung functions. Among those 128 workers completing spirometry, 31 (24%) showed obstructive changes with below normal ratio of FEV1/FVC. When lung function test result was compared to x-ray findings, obstructive lung function change was significantly associated with small irregular opacities (Fisher's Exact Test p=0.03). Silica dust exposure has been traditionally implicated for the chest x-ray findings among foundrymen, and in this study, 23% (13/56 samples) of the current silica dust exposure measurements were above 100 microg/m(3). The mean exposure from personal sampling was 106 microg/m(3). This study suggests that occupational exposures in foundrymen including silica may result in small irregular opacities. The results from this study are consistent with the report of obstructive lung function changes in coal miners with small irregular opacities.
Keywords
Respiratory-system-disorders; Pulmonary-system-disorders; Lung-disorders; Foundries; Steel-foundries; Foundry-workers; Diagnostic-tests; Chest-X-rays; X-ray-analysis; X-ray-diagnosis; Pulmonary-function-tests; Spirometry; Dust-exposure; Silica-dusts; Health-surveys; Questionnaires; Smoking; Sulfur-oxides; Employee-exposure; Analytical-instruments; Analytical-processes; Airway-obstruction
