Review of carcinogenicity of asbestos and proposal of approval standards of an occupational cancer caused by asbestos in Korea

Carcinogenicity of asbestos has been well established for decades and it has similar approval standards in most advanced countries based on a number of studies and international meetings. However, Korea has been lagging behind such international standards. In this study, we proposed the approval standards of an occupational cancer due to asbestos through intensive review on the Helsinki Criteria, post-Helsinki studies, job exposure matrix (JEM) based on the analysis of domestic reports and recognized occupational lung cancer cases in Korea. The main contents of proposed approval standards are as follows; (1) In recognizing an asbestos-induced lung cancer, diagnosis of asbestosis should be based on CT. In addition, initial findings of asbestosis on CT should be considered. (2) High Exposure industries and occupations to asbestos should be also taken into account in Korea (3) An expert's determination is warranted in case of a worker who has been concurrently exposed to other carcinogens, even if the asbestos exposure duration is less than 10 years. (4) Determination of a larynx cancer due to asbestos exposure has the same approval standards with an asbestos-induced lung cancer. However, for an ovarian cancer, an expert's judgment is necessary even if asbestosis, pleural plaque or pleural thickening and high concentration asbestos exposure are confirmed. (5) Cigarette smoking status or the extent should not affect determination of an occupational cancer caused by asbestos as smoking and asbestos have a synergistic effect in causing a lung cancer and they are involved in carcinogenesis in a complicated manner.

Review on Potential Risk Factors in Wafer Fabrication Process of Semiconductor Industry / 대한산업의학회지

OBJECTIVES: To associate work in the semiconductor industry, including silicon wafer fabrication, with cancer risks or mortality and other adverse health effects, the operation of wafer fabrication should initially be understood. A detailed study on the fabrication operation allows retrospective exposure to be assessed and wafer fabrication workers to be classified into similar exposure groups. Therefore, the objective of this study was to comprehensively review silicon wafer fabrication operations and related hazardous materials and agents. METHODS: The literatures related to semiconductor industry processes were reviewed from an occupational health viewpoint based on wafer manufacturing, wafer fabrication and packaging. The focus was especially related to the hazardous materials used in wafer fabrication industries. RESULTS: During the fabrication of silicon wafers, many toxic chemicals, a strong electric field and hazardous equipment are used. The process allows the integration of a three-dimensional array of electric circuits onto a silicon wafer substrate. Wafers are sliced from single crystal silicon and subject to a series of steps during the fabrication process, which alternatively adds and then selectively removes materials in layers from the surface of the wafer to create different parts of the completed integrated circuit. There are four major steps in this process; patterning, junction formation, thin film and metallization. CONCLUSIONS: In order to associate exposure to the hazard agents generated during wafer fabrication operations with adverse health effects the details of the operation should be completely studied, which will be helpful in both exposure assessments and epidemiological studies.

Epidemiologic Study of Preterm Birth in Chosun University Hospital / 대한산부인과학회잡지

OBJECTIVE: To investigate the change of prognosis of the preterm infants delivered in Chosun University Hospital. METHODS: A study was conducted for 236 newborns who were born at Chosun University hospital from January 1. 2000 to December 31, 2002. The data were collected by review of the hospital record. RESULTS: 1) The survival rate of the preterm infants who weigh below 999 gm was 2% and 68.4% in 1,000-1,499 gm of infants 90.9% in 1,500-1,999 gm of infants and 92.7% in 2,000-2,499 gm of infants respectively. 2) The survival rate of the preterm infants who born 25% at 25-26 weeks, 50% at 27-28 weeks, 80% at 29-30 weeks, 88.2% at 31-32 weeks, 94.4% at 33-34 weeks and 95% after 35 wks respectively. 3) The cause of preterm delivery were premature rupture of membranes (41.7%), preterm labor (23.7%), pregnancy induced hypertension (10.9%), multiple pregnancy (8.3%) etc. 4) The perinatal complications of the preterm infants were hyperbilirubinemia (27.5%), respiratory distress syndrome (24.2%), sepsis (11.4%) etc. CONCLUSION: To increase the survival rates of preterm infants, the preterm labor should be controlled by 27 week's gestation and the birth weight of 1,000 gm minimally.