Epidemiologic Characteristics of the Pneumoconiosis Patients in Manufacturing Industries

Lee, Won Chul; Yim, Hyeon Woo; Lee, Kyung Jae; Lee, Se Yong; Meng, Kwang Ho; Phee, Young Gyu; Kim, Hyun Wook; Koo, Jung Wan; Lim, Young; Yun, Im Goung

Abstract

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.