Systemic sclerosis due to crystalline silica exposure among jewelry workers in Korea: two case reports

BACKGROUND: Occupational exposure to crystalline silica is a potential risk factor for various systemic autoimmune diseases including systemic sclerosis. The etiology of systemic sclerosis is not conclusively known, but there are epidemiological studies that show the relationship between exposure to crystalline silica and risk of systemic sclerosis. Here we report, for the first time, two cases of crystalline silica-related systemic sclerosis in patients who worked in crystal processing in the jewelry-manufacturing field. CASE PRESENTATION: Case 1 is a 57-year-old man who had worked mainly in crystal processing for multiple jewelry-processing companies for 17 years, since the age of 15 years. He contracted tuberculosis at the age of 25 years and showed Raynaud's phenomenon of both the hands and feet at age 32 years. Digital cyanosis and sclerosis developed at approximately age 41 years. The patient was diagnosed with systemic sclerosis at age 48 years. Case 2 is a 52-year-old man who worked in crystal processing for various jewelry-processing companies for 7 years, since the age of 23 years. He first showed signs of cyanosis in the third and fourth digits of both hands at age 32 years, was diagnosed with Raynaud's syndrome at age 37 years, and was diagnosed with systemic sclerosis at age 38 years. Crystal processing is a detailed process that involves slabbing and trimming the selected amethyst and quartz crystals, which requires close proximity of the worker's face with the target area. In the 1980s and 1990s, the working hours were 12 h per day, and the working environment involved 15 workers crowded into a small, 70-m2 space with poor ventilation. CONCLUSION: Two workers who processed crystals with a maximum crystalline silica content of 56.66% developed systemic sclerosis. Considering the epidemiological and experimental evidence, exposure to crystalline silica dust was an important risk factor for systemic sclerosis. An active intervention is necessary to reduce exposure in similar exposure groups in the field of jewelry processing.

Serum Levels of IL-8 and ICAM-1 as Biomarkers for Progressive Massive Fibrosis in Coal Workers' Pneumoconiosis

Coal workers' pneumoconiosis (CWP) is characterized as a chronic inflammation of the lung associated with activation of macrophages and endothelial cells in the lung. The aim of the present study was to compare the levels of serum interleukin-8 (IL-8), macrophage inflammatory protein-1alpha (MIP-alpha), and intercellular adhesion molecule-1 (ICAM-1) as biomarkers for progressive massive fibrosis (PMF) in 106 subjects (27 non-CWP and 79 CWP patients). The levels of serum IL-8 (P<0.001) and ICAM-1 (P=0.001) of subjects with PMF were higher than those of non-CWP subjects. The IL-8 levels of PMF subjects were also higher than those of simple CWP subjects (P=0.003). Among the subjects without PMF, IL-8 levels in the subjects with International Labour Organization (ILO) category II or III were higher than those in the subjects with ILO category 0 (P=0.006) and with category I (P=0.026). These results suggest that high serum levels of IL-8 and ICAM-1, which are important as neutrophil attractants and adhesion molecules, are associated with PMF.

Serum Levels of IL-8 and ICAM-1 as Biomarkers for Progressive Massive Fibrosis in Coal Workers' Pneumoconiosis

Coal workers' pneumoconiosis (CWP) is characterized as a chronic inflammation of the lung associated with activation of macrophages and endothelial cells in the lung. The aim of the present study was to compare the levels of serum interleukin-8 (IL-8), macrophage inflammatory protein-1alpha (MIP-alpha), and intercellular adhesion molecule-1 (ICAM-1) as biomarkers for progressive massive fibrosis (PMF) in 106 subjects (27 non-CWP and 79 CWP patients). The levels of serum IL-8 (P<0.001) and ICAM-1 (P=0.001) of subjects with PMF were higher than those of non-CWP subjects. The IL-8 levels of PMF subjects were also higher than those of simple CWP subjects (P=0.003). Among the subjects without PMF, IL-8 levels in the subjects with International Labour Organization (ILO) category II or III were higher than those in the subjects with ILO category 0 (P=0.006) and with category I (P=0.026). These results suggest that high serum levels of IL-8 and ICAM-1, which are important as neutrophil attractants and adhesion molecules, are associated with PMF.

The Scope and Specific Criteria of Compensation for Occupational Diseases in Korea

The range of diseases covered by workers' compensation is constantly expanding. However, new regulations are required for the recognition of occupational diseases (ODs) because OD types evolve with changes in industrial structures and working conditions. OD criteria are usually based on medical relevance, but they vary depending on the social security system and laws of each country. In addition, the proposed range and extent of work-relatedness vary depending on the socio-economic conditions of each country. The Labor Standards Act (LSA) and the Industrial Accident Compensation Insurance Act (IACIA) of Korea employ lists based on their requirements without listing causes and diseases separately. Despite a considerable reshuffle in 2003, the basic framework has been maintained for 50 yr, and many cases do not fit into the international disease classification system. Since July 1, 2013, Korea has expanded the range of occupational accidents to include occupational cancers and has implemented revised LSA and IACIA enforcement decrees. There have been improvements to OD recognition standards with the inclusion of additional or modified criteria, a revised and improved classification scheme for risk factors and ODs, and so on.

Malondialdehyde and 3-Nitrotyrosine in Exhaled Breath Condensate in Retired Elderly Coal Miners with Chronic Obstructive Pulmonary Disease

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is an important cause of occupational mortality in miners exposed to coal mine dust. Although the inflammatory mediators involved in COPD have not been defined, many studies have shown that inflammatory mediators such as reactive oxygen and nitrogen species are involved in orchestrating the complex inflammatory process in COPD. METHODS: To investigate the relevance of exhaled biomarkers of oxidative and nitrosative stress in participants with COPD, we determined the levels of hydrogen peroxide, malondialdehyde (MDA), and 3-nitrotyrosine (3-NT) in exhaled breath condensate (EBC) in 90 retired elderly coal miners (53 non-COPD and 37 COPD participants). RESULTS: Mean levels of MDA (4.64 nM vs. 6.46 nM, p = 0.005) and 3-NT (3.51 nM vs. 5.50 nM, p = 0.039) in EBC were significantly higher in participants with COPD. The median level of MDA did show statistical difference among the COPD severities (p = 0.017), and the area under the receiver operating characteristic curve for MDA (0.67) for the diagnostic discrimination of COPD indicated the biomarker. The optimal cutoff values were 5.34 nM (64.9% sensitivity and 64.2% specificity) and 5.58 nM (62.2% sensitivity and 62.3% specificity) for MDA and 3-NT, respectively. The results suggest that high levels of MDA and 3-NT in EBC are associated with COPD in retired elderly miners. CONCLUSION: These results showed that the elevated levels of EBC MDA and EBC 3-NT in individuals with COPD are biomarkers of oxidative or nitrosative stress.

A Case of Occupational Asthma in a Plastic Injection Process Worker

OBJECTIVES: We report a case of death due to asthma attack in a plastic injection process worker with a history of asthma. METHODS: To assess task relevance, personal history including occupational history and medical records were reviewed. Samples of the substances utilized in the injection process were collected by visiting the patient's workplace. The work environment with the actual process was reproduced in the laboratory, and the released substances were evaluated. RESULTS: The medical records confirmed that the patient's conventional asthma was in remission. The analysis of the resins discharged from the injection process simulation revealed styrene, which causes occupational asthma, and benzenepropanoic acid, 3,5-bis(1,1-dimethylethyl)-4-hydroxy-, and octadecyl ester. Even though it was not the case in the present study, various harmful substances capable of inducing asthma such as formaldehyde, acrolein, and acetic acid are released during resin processing. CONCLUSION: A worker was likely to occur occupational asthma as a result of the exposure to the harmful substances generated during the plastic injection process.

A Case Report of Lung Cancer in a Horse Trainer Caused by Exposure to Respirable Crystalline Silica: An Exposure Assessment

Here, we present a case of lung cancer in a 48-year-old male horse trainer. To the best of our knowledge, this is the first such case report to include an exposure assessment of respirable crystalline silica (RCS) as a quartz. The trainer had no family history of lung cancer. Although he had a 15 pack/year cigarette-smoking history, he had stopped smoking 12 years prior to his diagnosis. For the past 23 years, he had performed longeing, and trained 7-12 horses per day on longeing arena surfaces covered by recycled sands, the same surfaces used in race tracks. We investigated his workplace RCS exposure, and found it to be the likely cause of his lung cancer. The 8-hour time weight average range of RCS was 0.020 to 0.086 mg/m3 in the longeing arena. Horse trainers are exposed to RCS from the sand in longeing arenas, and the exposure level is high enough to have epidemiological ramifications for the occupational risk of lung cancer.

Exposure Assessment Suggests Exposure to Lung Cancer Carcinogens in a Painter Working in an Automobile Bumper Shop

A 46-year-old man who had worked as a bumper spray painter in an automobile body shop for 15 years developed lung cancer. The patient was a nonsmoker with no family history of lung cancer. To determine whether the cancer was related to his work environment, we assessed the level of exposure to carcinogens during spray painting, sanding, and heat treatment. The results showed that spray painting with yellow paint increased the concentration of hexavalent chromium in the air to as much as 118.33 microg/m3. Analysis of the paint bulk materials showed that hexavalent chromium was mostly found in the form of lead chromate. Interestingly, strontium chromate was also detected, and the concentration of strontium chromate increased in line with the brightness of the yellow color. Some paints contained about 1% crystalline silica in the form of quartz.

Evaluation of Obstructive Pulmonary Function Impairment Risks in Pulmonary Emphysema Detected by Low-Dose CT: Compared with Simple Digital Radiography / 결핵및호흡기질환

BACKGROUND: Pulmonary emphysema (PE) is major cause of obstructive pulmonary function impairment (OPFI), which is diagnosed by spirometry. PE by high resolution CT is known to be correlated with OPFI. Recently, low dose CT (LDCT) has been increasingly used for screening interstitial lung diseases including PE. The aim of this study was to evaluate OPFI risks of subjects with PE detected by LDCT compared with those detected by simple digital radiography (SDR). METHODS: LDCT and spirometry were administered to 266 inorganic dust exposed retired workers, from May 30, 2007 to August 31, 2008. This study was approved by our institutional review board and informed consent was obtained. OPFI risk was defined as less than 0.7 of forced expiratory volume in one second (FEV1)/forced vital capacity (FVC), and relative risk (RR) of OPFI of PE was calculated by multiple logistic regression analysis. RESULTS: Of the 266 subjects, PE was found in 28 subjects (10.5%) by LDCT and in 11 subjects (4.1%) by SDR; agreement was relatively low (kappa value=0.32, p<0.001). FEV1 and FEV1/FVC were significantly different between PE and no PE groups determined by either SDR or LDCT. The differences between groups were larger when the groups were divided by the findings of SDR. When PE was present in either LDCT or SDR assays, the RRs of OPFI were 2.34 and 8.65, respectively. CONCLUSION: LDCT showed significantly higher sensitivity than SDR for detecting PE, especially low grade PE, in which pulmonary function is not affected. As a result, the OPFI risks in the PE group by LDCT was lower than that in the PE group by SDR.

Annual Changes of Lung Function in Retired Workers Exposed to Inorganic Dusts / 결핵및호흡기질환

BACKGROUND: The aim of this study was to investigate annual changes in pulmonary function in workers who were exposed to inorganic dust. METHODS: The subjects were 2,922 male patients who had been diagnosed with pneumoconiosis more than twice during 6 years from 2005 to 2010. RESULTS: Of the 2,922 cases, forced vital capacity (FVC) decreased by 54 mL in 1 year. In contrast, the annual change of forced expiratory volume in one second (FEV1) decreased by 56 mL. CONCLUSION: This is the first study that has investigated the annual change in pulmonary function in workers exposed to inorganic dust. The results will help estimate the pulmonary condition of patients who are unable to perform a pulmonary function test due to age or a disorder.

Development of Standard Digital Images for Pneumoconiosis

We developed the standard digital images (SDIs) to be used in the classification and recognition of pneumoconiosis. From July 3, 2006 through August 31, 2007, 531 retired male workers exposed to inorganic dust were examined by digital (DR) and analog radiography (AR) on the same day, after being approved by our institutional review board and obtaining informed consent from all participants. All images were twice classified according to the International Labour Office (ILO) 2000 guidelines with reference to ILO standard analog radiographs (SARs) by four chest radiologists. After consensus reading on 349 digital images matched with the first selected analog images, 120 digital images were selected as the SDIs that considered the distribution of pneumoconiosis findings. Images with profusion category 0/1, 1, 2, and 3 were 12, 50, 40, and 15, respectively, and a large opacity were in 43 images (A = 20, B = 22, C = 1). Among pleural abnormality, costophrenic angle obliteration, pleural plaque and thickening were in 11 (9.2%), 31 (25.8%), and 9 (7.5%) images, respectively. Twenty-one of 29 symbols were present except cp, ef, ho, id, me, pa, ra, and rp. A set of 120 SDIs had more various pneumoconiosis findings than ILO SARs that were developed from adequate methods. It can be used as digital reference images for the recognition and classification of pneumoconiosis.

The Application of Impulse Oscillometry (IOS) in the Workers Who had been Exposed to Inorganic Dust Induced Early Airway Obstruction / 결핵및호흡기질환

BACKGROUND: We tried to examine the small airway diseases which can be found early, in workers exposed to inorganic dusts. This is measured in normal breath by using the impulse oscillometry (IOS). METHODS: The Pulmonary function test (forced vital capacit [FVC], forced expiratory volume in one second [FEV1], forced expiratory flow between 25% and 75% of vital capacity [FEF25-75]), IOS resistance (Rrs at 5, 10, 15, 20, 25, 35 Hz) and reactance (Xrs at 5, 10, 15, 20, 25, 35 Hz) were measured for 454 workers. The subjects were classified into 173 workers of normal (38.1%) and 281 patients with pneumoconiosis (61.9%). RESULTS: There were significant differences between normal and patients with FVC (3.82+/-0.61 vs. 3.53+/-0.56 L), FEV1 (2.67+/-0.63 vs. 2.35+/-0.48 L), and FEF25-75 (1.88+/-0.95 vs. 1.47+/-0.80 L/sec) between groups (p0.05), and there were significant differences between normal and patients with reactance (Xrs) 15 Hz (0.003+/-0.05 vs. -0.006+/-0.04 kPa/L/s), 20 Hz (0.043+/-0.05 vs. 0.031+/-0.04 kPa/L/s), and 35 Hz (0.141+/-0.05 vs. 0.131+/-0.05 kPa/L/s) between groups (p<0.05). CONCLUSION: We could find out that 15 Hz, 20 Hz, and 35 Hz values of reactance were significantly influenced by pneumoconiosis. When usefulness and reproducibility to carry out the IOS are considered, it is thought that in future work will be required to draw the reference values for normal Korean persons.

Characteristics of Occupational Lung Cancer from 1999 to 2005 / 대한산업의학회지

OBJECTIVES: The aim of this study was to investigate the characteristics of occupational lung cancer. METHODS: We analyzed the characteristics of 53 occupational lung cancer cases among 128 lung cancer cases applied for industrial accident compensation insurance benefits and referred for the decision of work-relatedness between 1999 and 2005. Statistical analysis was conducted using the Chi-square test on 128 lung cancer cases. RESULTS: The age of diagnosis, smoking history, and cell type of lung cancer cases were not significantly different between 53 cases of occupational lung cancer and 75 cases of non-occupational lung cancer (p>.05). Here is a list of occupational lung cancer case numbers associated with certain carcinogens were: 33(62.3%) cases with asbestos, 23(43.4%) cases with polycyclic aromatic hydro carbon (PAH), 17 cases(32.1%) with chromium VI (Oxidation state), 14 cases(26.4%) with crystalline silica, 12 cases (22.6%) with nickel compounds, 2 cases(3.8%) with radon daughters, and 1 case(1.9%) with arsenic. Eighteen cases(34.0%) of occupational lung cancer had exposures to a single carcinogen, and 35 cases (66.0%) had exposures to more than 2 carcinogens. Job types associated with occupational lung cancer cases were: 16 cases(30.2%) with maintenance, 13 cases(24.5%) with welding; 6 cases(11.3%) with grinding; 4 cases(7.5%) with foundry; 3 cases(5.7%) with driving, casting, and painting' and 14 cases (26.4%) with 'other'. CONCLUSIONS: This study identified the characteristics of occupational lung cancer through the analysis of the age of diagnosis, smoking history, cell type, job, and carcinogen. There is no difference between occupational lung cancer and non-occupational lung cancer except exposure to the carcinogens. these results indicate that past exposure to occupational carcinogens remains an important determinant of occupational lung cancer occurrence.

Serum Levels of Interleukin-8 and Tumor Necrosis Factor-alpha in Coal Workers' Pneumoconiosis: One-year Follow-up Study

OBJECTIVES: Various cytokines induced by inhalation of coal dust may mediate inflammation and lead to tissue damage or fibrosis, such as coal workers' pneumoconiosis (CWP). METHODS: To investigate the relevance of serum cytokines in CWP, the levels of serum interleukin-8 (IL-8) and tumor necrosis factor-alpha (TNF-alpha) as CWP biomarkers in 110 retired coal miners (22 controls and 88 CWP subjects) were related to cross sectional findings and 1-year progressive changes of the pneumoconiosis. Progressive changes of CWP were evaluated by paired comparison of chest radiographs. Analysis by a receiver operating characteristic curve assessed the biomarker potential of each cytokine. RESULTS: The mean serum IL-8 level was significantly higher in CWP compared to controls and IL-8 levels correlated with the degree of CWP. The median serum TNF-alpha level was significantly higher in subjects with progressive CWP compared to subjects without CWP progression. The area under the ROC curve for IL-8 (0.70) and TNF-alpha (0.72) for CWP identification and progression, respectively, indicated the biomarker potential of the two cytokines. Serum cutoff values of IL-8 and TNF-alpha were 11.63 pg/mL (sensitivity, 69%; specificity, 64%) and 4.52 pg/mL (sensitivity, 67%; specificity, 79%), respectively. CONCLUSION: The results suggest that high levels of serum IL-8 are associated with the presence of CWP and those of serum TNF-alpha are associated with the progression of CWP.

Current Status of Pneumoconiosis Patients in Korea

This study identifies the number of pneumoconiosis patients after eliminating deceased patients between 2003 and 2008 as of January 1st and estimates it for the next five years. From 2003 to 2008, the pneumoconiosis patients were 16,929, 17,224, 17,366, 17,566, 17,542, and 17,546, respectively. The number of pneumoconiosis patients will have increased by 1,014 from 2008 to 18,560 in 2013 after applying the average change rates taken from 2003 to 2007. It takes 15-20 yr to develop coal workers' pneumoconiosis (the main cause in Korea) and patients will continue to be diagnosed with pneumoconiosis for some years to come since it has only been 20 yr since the decline of the coal mining industry in Korea. In addition, pneumoconiosis patients are increasing in industries in which the risk of pneumoconiosis was relatively low shows the necessity to improve dust-exposed workplace environments.

Changes of Pulmonary Disability Grades according to the Spirometry Reference Equations / 결핵및호흡기질환

BACKGROUND: The aim was to estimate the differences between pulmonary disability grades according to the spirometry reference equations (the Korean equation and the Morris equation). METHODS: Spirometry was performed on 16,916 male and 1,353 female special examination for pneumoconiosis, in the period of 2007~2009. Changes in predictive values for forced expiratory volume in one second (FEV1), forced vital capacity (FVC) and FEV1/FVC and in disability grade were evaluated using both equations. RESULTS: Mean FVCs for men and women were 4,218.7 mL and 2,801.5 mL in predictive values after the application of the Korean equation, and 3,763.9 mL and 2,395.6 mL after the Morris equation, respectively. Compared with the Morris equation, the Korean equation showed 10.8% and 14.5% of excesses for men and women (p<0.001). Mean FEV1s for men and women were 3,102.5 mL and 2,107.1 mL in the Korean equation, and 2,667.8 mL and 1,699.6 mL in the Morris equation, respectively. Compared with the Morris equation, the Korean equation showed 14.0% and 19.3% of excesses for men and women (p<0.001). Men and women who showed the changes of disability grades using the Korean equation in place of the Morris equation were 23.9% (4,052/16,916) and 22.9% (311/1,353) on FVC, and 23.1% (3,913/16,916) and 10.7% (145/1,353) on FEV1. CONCLUSION: Applying different reference equations for spirometry has resulted in changes for disability grades in special examination for pneumoconiosis.

A Case of Reactive Airways Dysfunction Syndrome in a Synthetic Resin Manufacture Factory / 대한산업의학회지

BACKGROUND: Reactive airways dysfunction syndrome (RADS), which represents between 5% and 18% of new-onset, work-related asthma, remains underreported in spite of increasing reports of occupational asthma cases through occupational asthma surveillance in Korea. We report a 61-year-old male who developed RADS after exposure to a high level of toxic gases from a workplace accident. CASE: The patient who had worked for 21 years at a PVC manufacture factory and had retained good health until Aug 22, 2007, when he was exposed to PVC (polyvinyl chloride), DEHP (Di (2-Ethylhexyl) Phthalate), dibutyl tin maleate and epoxidized soybean oil gases from a heated mixer. Within several minutes of exposure, he developed coughing, rhinorrhea, dyspnea and wheezing. Pulmonary function tests (PFTs) showed an FVC of 3.81 L(82% of predicted), FEV1 of 1.63 L/s (50% of predicted), FEV1/FVC% of 43 %, and FEV1 of 1.80 L/s that increased by 170 ml and 10.4% in response to bronchodilator. After 7 months of treatment with inhaled steroids and bronchodilators, repeat PFTs showed an FVC of 6.56 L(143.5% of predicted), FEV1 of 3.21 L(99.3% of predicted), and FEV1/FVC% of 48.9%. A methacholine challenge test was negative at a concentration of 25 mg/ml. CONCLUSION: RADS occurred due to exposure to raw material vapors or their thermal decomposition products.

A Study on the N-methylformamide Excretion Rate of Workers at Synthetic Leather Factories in Korea / 대한산업의학회지

This study was conducted to examine the excretion rate of dimethylformamide (DMF) from the workers exposed to DMF. The study was done at two synthetic leather factories located in Kyeonggi-do from the period of May 2 to 30, 1996. N-methyl- formamide (NMF) concentrations in urine were measured and compared by the three exposure level of DMF in air. The mean concentration of the Low (dry and winder part). Moderate (rinsing part) and High (mixing and coating part) exposure group were 3.99+/-3.54. 10.19 +/-5.69 and 32.10+/-7.87 mg/m3 during workshift of 8 hours, respectively. The mean concentration of urinary N-methylforinamide (NMF) were 2.13+/-2.58, 11.16+/-4.98 and 26.24 +/-7.35 mg/g creatinine, respectively. The concentration of NMIF in urine could reach to maximum in 3 hours and was reduced nearly to zero in about 18 hours after exposure to DMF.

Cumulative Trauma Disorders among Telephone Directory Assistance Operators / 대한산업의학회지

To evaluate the prevalence of cumulative trauma disorders in relation to ergonomic evaluation of their work, 260 female directory assistance operators employed in three branch facilities of the nation-wide telecommunication company. Ergonomic evaluation of the work status was done by two industrial hygienists through inspection. Workers were surveyed with standardized self-administered questionnaire and examined by family physicians and an orthopaedician for cumulative trauma disorders. Laboratory examination of serum aspartate aminotransferase(AST), creatinine phosphokinase(CPK), aldolase and rheumatoid factor was done and X-ray of cervical spine and both shoulders was taken from all subjects and nerve conduction velocity test was done on 57 subjects with suspected nerve entrapment cases. Cumulative trauma disorders were categorized into 3 category according to work-relatedness of the disorders. On ergonomic evaluation of the working posture and work environment, improvement of work posture revealed inappropriate postures and devices. Mean age of the subjects were 39 years old and more than 80% graduated high school or above. Ninety-eight percent of the workers employed in the company for more than 15 years and 74.6% of the workers worked at the VDT job for more than 4 years. Mean daily work hours was 8.0 hours per day and mean break hours was 90.5 minutes per day with mean extra work hours of 10.7 hours per month. Mean daily calls were 1128.6 calls in maximum and 864.8 calls in minimum. On laboratory examination, 13 (5.0%) workers had abnormal AST, 53(20.4%) had abnormal CPK, and 1 (0.4%) had abnormal aldolase level. On x-ray examination of cervical spine, 111 (42.7%) had loss of or reversed normal cervical lordosis, 10(3.8%) had narrowing of intervertebral space. Nerve conduction velocity test was abnormal in 11 (19.2%) among 57 workers. Among disorders categorized as work-related, 131 (50.4%) were diagnosed to have fatigue myalgia of levator scapulae, 108 (41.5%) had cervical strain or sprain, 47 (18.1%) had fatigue arthralgia of phalangeal joints, and 47 (18.1%) had probable carpal tunnel syndrome, in 10 (3.8%) of those diagnosis was confirmed electrophysiologically. Age, seniority, work duration at present job, workload nor location of facilities were associated with the prevalence of symptoms nor specific diagnoses on simple statistical analysis and multiple logistic regression, which deems to be due to highly selected and homogeneous characteristics of the study subjects. Above results shows that cumulative trauma disorders are very prevalent among directory assistance operators and elaborate effort is needed to reduce the cumulative trauma disorders among the operators.

Factors affecting Reading Agreement of Pneumoconiotic Findings / 대한산업의학회지

To find the factors affecting reading agreement of pneumoconiotic findings of simple chest P-A films and to develop the definite quality assurance (Q.A) program for the reading of pneumoconiosis, I gathered the reading reports of the previously developed forty four chest films from nationwide thirty nine radiologists and compared those with the findings decided by the stepwise panel readings of the highly qualified eight radiologists. The reading agreement of profusion by complete or short classification was higher in the radiologists with sufficient reading experiences of pneumoconiosis during residency training. It was also higher in the radiologists with reference to ILO standard films or those working in the agencies for pneumoconiosis within one category of profusion by complete classification. Other factors were not related with the reading agreement of profusion. In small opacity and pleural thickening, there were not any consistent and meaningful findings between the reading agreement and radiologists' characteristics. From the above results, it is necessary to develop the Q.A program to improve the reading agreement of pneumoconiotic findings, especially small opacity and pleural lesions.