Epidemiologic Characteristics of the Pneumoconiosis Patients in Manufacturing Industries / 한국역학회지

Pneumoconiosis was the first reported occupational disease in Korea and was the most common one until 1990. In the past, most pneumoconiosis patients were found among underground workers in various mines. Recently this occupational disease has increasingly affected workers in manufacturing industries such as ship building, briquette, glass, foundry industries, and so on. In order to investigate the scale of pneumoconiosis in manufacturing industries, we evaluated the detailed medical examination records and insurance deliberation data from 1989 until 1994. Information about work history, medical history, and exposure dust type were collected for each member of the study population. All chest X-rays were interpreted and classified using the International Labor Organization(ILO) scale by three radiologist who have had extensive experience evaluation pneumoconiosis. For the calculation of the incidence rate of manufacturing pneumoconiosis, we analyzed the Specific Health Examination data and estimated the population at risk as a denominator of the incidence rate. We divided manufacturing industry into 9 subclasses by industrial classification and estimated the incidence rate of pneumoconiosis per 100,000 workers at risk respectively. The results were as follows, 1. 485 workers were newly diagnosed with pneumoconiosis during 6 years from 1989 to 1994. 482 workers had radiographs consistent with simple pneumoconiosis and three with progressive massive fibrosis. Among those with radiographs consistent with simple pneumoconiosis, 395 workers(81.4%) had category 1 profusion, 76 workers(15.7%) had category 2 profusion and 11 workers(2.3%) had category 3 profusion. 2. Almost all of them were male(97.9%) and their average age was 48.3 uears. Manufacturing pneumoconiosis patients were more common in their forties and fifties. 3. The average duration of dust exposure required for the occurrence of pneumoconiosis was 13.5 years. In the case of metal products manufacturing which is mostly related to welding, the average duration of dust exposure was 12.0 years. It was slightly shorter than other manufacturing industries. The average duration of dust exposure required for the occurrence of pneumoconiosis seemed to be shorter in welding operators, even though the welders lung has a weak tissue reaction and the condition is reversible. 4. According to the Industrial classification, 299 cases(61.6%) were found in workers of non-metal mineral products manufacturing, and 56 cases(11.5%) in basic metals industry. 5. The average annual incidence rate of pneumoconiosis in manufacturing industries from 1990 to 1994 was 56.6 per 100,000 workers at risk. On sub-classification, the average annual incidence rate of pneumoconiosis in non-metal mineral products manufacturing industry was the highest among them, showing 479 per 100,000 workers at risk. 6. Radiologic prevalence rate of tuberculosis in these cases was 6.6%. 7. X-ray category profusion in newly diagnosed manufacturing pneumoconiosis varied according to sub-classification. The proportion of category 1 profusion in metal products manufacturing is higher than that in non-metal mineral products manufacturing. 8. The type pattern of small round opacities varied according to sub-classification in manufacturing industry. In non-metal mineral products manufacturing, the small round opacity were observed 25.9% cases with p type, 72.1% with q type and 2.0% with r type respectively. But in metal products manufacturing, the small round opacity were observed 51.4% cases with p type and 48.6% with q type respectively. The cause might be that the exposed dust is different according to job. 9. The type pattern of small round opacities varied according to dust type. Metal dusts showed similar radiologic shape to the coal dusts, but welding fume showed more frequent p type(60.3%) and less frequent q type(377%). rock dust showed less frequent p types(18.3%) and more frequent q types(75.3%). Since the incidence rate of non-metal manufacturing workers showed higher rate than other manufacturing industry, Preventive measures and health care education should be carefully carried out in these workers.

An Association between Brain MRI and Neurologic Findings in Welders Exposed to Manganese Fume / 대한산업의학회지

This study was carried out to investigate the relationship between brain magnetic resonance imaging (MRI) and neurological findings in welders exposed to manganese fume. Thirty five welders from a bus manufacturing factory who were occupationally exposed to low dose manganese fume were examined. We collected the information on the demo graphic factors and welding careers. Laboratory investigations included blood and urine manganese concentration and blood chemistry. Brain MRI was checked, and high signal intensity of the globus pallidus was graded from 0 to 3 compared to the white matter of the frontal lobe. Neurologic examination wart carried out. The results were as follows ; 1. The mean age of workers was 48.3+/-5.7 years, mean duration of welding was 21.4 +/-5.6 Years. 2. On brain MRI, high signal intensity in the globes pallidus was observed in 27 workers (77.1%) Among them, 18 cases (66.7%) showed remarkably high signal intensity (grade 2) Mean concentration of blood manganese was higher in those with high signal intensity and correlated to the grade of high signal intensity (p=0.02) 3. On neurologic examination, no workers showed the finding of typical parkinsonism. But 11 workers (31.4%) showed subtle neurological abnormalities such as gait without associated arm movement, postural instability, intention tremor, and so on. Blood manganese concentration of neurologically abnormal group was 2.4+/-0.7 microgram/dL, which was significantly higher, compared to 1.8+/-0.7 microgram/dL of neurologically normal group (p=0.03). 4. Among 27 workers who showed high signal intensity on brain MRI, 10 workers (37%) were neurologically abnormal. Higher grade of signal intensity on globus pallidus showed higher rate of neurologic abnormality (p<0.05) Especially postural instability and gait without associated arm movement were prominent findings. These bindings suggest that high signal intensity on brain MRI might be associated with a prodromal sign of manganese intoxication. Careful neurologic examination should be tool lowed up on welders showing high signal intensity in the golbus pallidus of brain MRI.

The Effects of Knowledge and Attitude about Noise on Hearing Conservation Behavior and Hearing Loss / 대한산업의학회지

This study was conducted to investigate knowledge and attitude factor related to hearing conservation and to evaluate the effect of knowledge and attitude about noise on hearing conservation behavior and hearing loss among workers exposed to noise. We investigated the questionnaires of knowledge and attitude about noise and hearing conservation behavior and hearing loss among 355 study subjects from March, 1998 to June, 1998. The results were as follows; We extracted following 5 factors from 26 questionnaire items of knowledge and attitude about noise; knowledge of noise and concern to the control noise (factor 1), general perceived susceptibility (factor 2), relative perceived susceptibility compared with colleagues(factor 3), concern to the hearing protective devices(factor 4), concern to the hearing and noise assessment (factor 5). Knowledge and attitude factors affecting the hearing conservation behavior were general perceived susceptibility in the case of wearing hearing protective devices and knowledge of noise and concern to the control noise in the case of suggestion for hearing conservation. But, in the case of intentional avoiding noise exposure, concern to the hearing protective devices was a significant factor with concern to the hearing and noise assessment. Knowledge and attitude factors affecting hearing loss in 1 kHz were relative perceived susceptibility compared with colleagues and concern to the hearing protective devices, and in 4 KHz were relative perceived susceptibility compared with colleagues and general perceived susceptibility.