Achievements, Problems, and Future Direction of the Quality Control Program for Special Periodic Health Examination Agencies in Republic of Korea

The ultimate goal of the quality control program for special periodic health examination agencies is to diagnose the health condition of a worker correctly, based on accurate examination and analysis skills, leading to protect the worker’s health. The quality control program on three areas, chemical analysis for biological monitoring since 1995, and pneumoconiosis, audiometric testing since 1996, has contributed to improve the reliability of occupational health screenings by improving the issues including standardization of testing methods, tools, diagnostic opinions, and reliability of analysis for biological monitoring. It has contributed to improving the reliability of occupational health monitoring by rectifying the following issues associated with previous monitoring: absence of standardized testing methods, testing tools that are not upgraded, mismatching diagnostic opinions, and unreliable results of biological specimen analysis. Nevertheless, there are issues in need of further improvement such as lack of expertise or the use of inappropriate method for health examination, and passive and unwilling participation in the quality control. We suggested solutions to these problems for each area of quality control program. Above all, it is essential to provide active support for health examiners to develop their expertise, while encouraging all the health screening agencies, employers, and workers to develop the desire to improve the system and to maintain the relevance.

Effects of Beryllium on Human Serum Immunoglobulin and Lymphocyte Subpopulation

To investigate the effects of short-term exposure of beryllium on the human immune system, the proportion of T-lymphocytes such as CD3+, CD4+, CD8+, CD95, and NK cells, andthe proportion of B cells and TNFalpha level in peripheral blood and immunoglobulins in the serum of 43 exposed workers and 34 healthy control subjects were studied. External exposure to beryllium was measured by atomic absorption spectrometer as recommended by the NIOSH analytical method 7300. T lymphocyte subpopulation analysis was carried out with flow cytometer. The working duration of exposed workers was less than 3 months and the mean ambient beryllium level was 3.4 microg/m3, 112.3 microg/m3, and 2.3 microg/m3 in molding (furnace), deforming (grinding), and sorting processes, respectively (cited from Kim et al., 2008). However, ambient beryllium level after process change was non-detectable (< 0.1 microg/m3). The number of T lymphocytes and the amount of immunoglobulins in the beryllium-exposed workers and control subjects were not significantly different, except for the total number of lymphocytes and CD95 (APO1/FAS). The total number of lymphocytes was higher in the beryllium-exposed individuals than in the healthy control subjects. Multiple logistic regression analysis showed lymphocytes to be affected by beryllium exposure (odd ratio = 7.293; p < 0.001). These results show that short-term exposure to beryllium does not induce immune dysfunction but is probably associated with lymphocytes proliferation.

Subclinical interstitial lung damage in workers exposed to indium compounds

OBJECTIVES: The present study was designed to determine whether there is a relationship between indium compound exposure and interstitial lung damage in workers employed at indium tin oxide manufacturing and reclaiming factories in Korea. METHODS: In 2012, we conducted a study for the prevention of indium induced lung damage in Korea and identified 78 workers who had serum indium or Krebs von den Lungen-6 (KL-6) levels that were higher than the reference values set in Japan (3 microg/L and 500 U/mL, respectively). Thirty-four of the 78 workers underwent chest high-resolution computed tomography (HRCT), and their data were used for statistical analysis. RESULTS: Geometric means (geometric standard deviations) for serum indium, KL-6, and surfactant protein D (SP-D) were 10.9 (6.65) microg/L, 859.0 (1.85) U/mL, and 179.27 (1.81) ng/mL, respectively. HRCT showed intralobular interstitial thickening in 9 workers. A dose-response trend was statistically significant for blood KL-6 levels. All workers who had indium levels > or =50 microg/L had KL-6 levels that exceeded the reference values. However, dose-response trends for blood SP-D levels, KL-6 levels, SP-D levels, and interstitial changes on the HRCT scans were not significantly different. CONCLUSIONS: Our findings suggest that interstitial lung changes could be present in workers with indium exposure. Further studies are required and health risk information regarding indium exposure should be communicated to workers and employers in industries where indium compounds are used to prevent indium induced lung damage in Korea.

Assessment of Arsenic Exposure by Measurement of Urinary Speciated Inorganic Arsenic Metabolites in Workers in a Semiconductor Manufacturing Plant

OBJECTIVES: The purpose of this study was to evaluate the exposure to arsenic in preventive maintenance (PM) engineers in a semiconductor industry by detecting speciated inorganic arsenic metabolites in the urine. METHODS: The exposed group included 8 PM engineers from the clean process area and 13 PM engineers from the ion implantation process area; the non-exposed group consisted of 14 office workers from another company who were not occupationally exposed to arsenic. A spot urine specimen was collected from each participant for the detection and measurement of speciated inorganic arsenic metabolites. Metabolites were separated by high performance liquid chromatography-inductively coupled plasma spectrometry-mass spectrometry. RESULTS: Urinary arsenic metabolite concentrations were 1.73 g/L, 0.76 g/L, 3.45 g/L, 43.65 g/L, and 51.32 g/L for trivalent arsenic (As3+), pentavalent arsenic (As5+), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), and total inorganic arsenic metabolites (As3+ + As5+ + MMA + DMA), respectively, in clean process PM engineers. In ion implantation process PM engineers, the concentrations were 1.74 g/L, 0.39 g/L, 3.08 g/L, 23.17 g/L, 28.92 g/L for As3+, As5+, MMA, DMA, and total inorganic arsenic metabolites, respectively. Levels of urinary As3+, As5+, MMA, and total inorganic arsenic metabolites in clean process PM engineers were significantly higher than that in the non-exposed group. Urinary As3+ and As5+ levels in ion implantation process PM engineers were significantly higher than that in non-exposed group. CONCLUSION: Levels of urinary arsenic metabolites in PM engineers from the clean process and ion implantation process areas were higher than that in office workers. For a complete assessment of arsenic exposure in the semiconductor industry, further studies are needed.

The Effects of Hazardous Chemical Exposure on Cardiovascular Disease in Chemical Products Manufacturing Workers

The purpose of this study was to understand the mechanism of cardiovascular disease (CVD) caused by exposure to hazardous chemicals. We investigated changes in the symptoms of metabolic syndrome, which is strongly related to CVD, and in levels of other CVD risk factors, with a special emphasis on the roles of catecholamines and oxidative stress. The results revealed that neither body mass index (BMI) nor waist and hip circumferences were associated with exposure to hazardous chemicals. Among metabolic syndrome criteria, only HDL-cholesterol level increased on exposure to hazardous chemicals. Levels of epinephrine (EP) and norepinephrine (NEP) were not influenced by exposure to hazardous chemicals; however, the total antioxidative capacity (TAC) reduced because of increased oxidative stress. Both hazardous chemical exposure level and metabolite excretion were related to EP, NEP, and the oxidative stress index (OSI). Logistic regression analysis with these factors as independent variables and metabolic syndrome criteria as dependent variables revealed that EP was associated with blood pressure, and NEP with metabolic syndrome in the chemical-exposed group. In conclusion, the results suggest that reactive oxygen species generated and oxidative stress due to exposure to hazardous chemicals act as mediators and cause changes in the physiological levels of EP and NEP to increase blood pressure. This ultimately leads to the development of CVD through increase in cholesterol, triglyceride, and blood glucose levels by lipid peroxidation.

The Effects of Long-Term, Low-Level Exposure to Monocyclic Aromatic Hydrocarbons on Worker's Insulin Resistance

OBJECTIVES: This study was designed to investigate whether long-term, low-level exposure to monocyclic aromatic hydrocarbons (MAHs) induced insulin resistance. METHODS: The subjects were 110 male workers who were occupationally exposed to styrene, toluene, and xylene. One hundred and ten age-matched male workers who had never been occupationally exposed to organic solvents were selected as a control group. Cytokines, which have played a key role in the pathogenesis of insulin resistance, and oxidative stress indices were measured. Assessment of exposure to MAHs was performed by measuring their ambient levels and their urinary metabolites in exposed workers, and the resulting parameters between the exposed group and non-exposed control groups were compared. RESULTS: There was no significant difference in general characteristics and anthropometric parameters between the two groups; however, total cholesterol, fasting glucose, fasting insulin, and homeostasis model assessment of insulin resistance levels were significantly higher in the exposed group. Phenylglyoxylic acid levels showed significant association with tumor necrosis factor-alpha, total oxidative status, and oxidative stress index via multiple linear regression analysis. Further, there was a negative correlation between methylhippuric acid levels and total anti-oxidative capacity, and there was a significant relationship between MAHs exposure and fasting glucose levels, as found by multiple logistic regression analysis (odds ratio = 3.95, 95% confidence interval = 1.074-14.530). CONCLUSION: This study indicated that MAHs increase fasting glucose level and insulin resistance. Furthermore, these results suggested that absorbing the organic solvent itself and active metabolic intermediates can increase oxidative stress and cytokine levels, resulting in the changes in glucose metabolism and the induction of insulin resistance.

The Relationship between Job Stress and Musculoskeletal Symptoms in Migrant Workers / 대한산업의학회지

OBJECTIVE: To investigate the musculoskeletal symptoms of migrant workers. We focused on the relationship between job stress and musculoskeletal symptoms. METHOD: A questionnaire was administered to 502 migrant workers who visited NGO migrant worker centers located in Gyung-gi province. A structured, self-reported questionnaire was administered to participants in order to capture the following information: sociodemographics, health factors including past medical history, work related characteristics, job stress, and musculoskeletal symptoms. The job stress questionnaires were used according to KOSS-26 and musculoskeletal symptoms were measured using KOSHA Code H-30-2003. We used multiple logistic regression analysis to assess the relationship between risk factors which included job stress, and musculoskeletal symptoms. RESULTS: The prevalence rate of musculoskeletal symptoms in survey subjects was 35.1%. Other than job stress factors, past medical history was the only factor that had a statistical relationship to musculoskeletal symptoms (P<0.01). In the domains of job stress, physical environment (OR 1.62, 95% CI: 1.03~2.54), job demand (OR 2.43, 95% CI: 1.46~4.03), job insecurity (OR 1.59, 95% CI: 1.03~2.47), occupational climate (OR 2.30, 95% CI: 1.27~4.19) were most likely experience musculoskeletal symptoms. CONCLUSION: The job stress factor appeared to correlate more with musculoskeletal symptoms than with sociodemographics or other factors. Hence, in order to prevent migrant worker's musculoskeletal symptoms, we believe that intervention in job stress (physical environment, job demand, job insecurity, occupational climate) is necessary.

The Relationship between Job Stress and Depressive Symptoms in Migrant Workers in Kyung-gi Province in Korea / 대한산업의학회지

OBJECTIVES: To investigate the mental health status of migrant workers. We focused on the relationship between depressive symptoms and job stress. METHEOD: A questionnaire was administered to 488 migrant workers who visited NGO migrant worker centers located in Kyung-gi province. A structured, self-reported questionnaire was used to assess each responder's sociodemographics, work related characteristics, health behaviors, past medical history, job stress and depression symptoms. The job stress questionnaire was used according to KOSS-26 and depression symptoms were measured using CES-D, which was translated into Korean. We used multiple logistic regression analysis to assess the relationship between risk factors included job stress and depression symptoms. RESULTS: The prevalence of depression symptoms in survey subjects was 25.2%, but the prevalence of non-Chinese nationalities and illegal workers were 32.1% and 32.8%, respectively. Adjusting for confounding factors, job stress (OR 2.55, 95% CI=1.30-4.99) had a statistical meaningful relationship with depression symptoms. Among job stress domains, physical environment (OR 2.97, 95% CI=1.59-5.53), job demand (OR 2.33, 95% CI=1.26-4.32) and occupational climate(OR 3.10, CI=1.49-6.48) were most likely to experience depression symptoms. CONCLUSIONS: The prevalence of depressive symptoms among the study subjects was similar to the prevalence among the general population in Korea, but higher than that among the Korean workers. In particular, the prevalence among non-Chinese and illegal workers was higher. However, the job stress factor appeared to have a more direct correlation with depressive symptoms than the sociodemographic factors of nationality or residential status. Hence, in order to prevent depressive symptoms of the migrant workers, we believe that intervention on job stress is necessary.

Effects of Obesity on the Physiological Levels of Adiponectin, Leptin and Diagnostic Indices of Metabolic Syndrome in Male Workers / 산업간호학회지

PURPOSE: The aim of this study was to examine the effects of obesity on the physiological levels of adiponectin, leptin and components of metabolic syndrome (MS) in male workers, aged 30-40 years. METHODS: Body mass index (BMI) was measured with Anthropometric equipment. Blood pressure and serum parameters were measured with an automatic digital sphygmomanometer and autochemical analyzer, respectively. Adiponectin and leptin were analysed by ELISA kits and MS was defined based on the NCEP-ATP III. RESULTS: Body fat mass of waist and hip, systolic and diastolic blood pressure were significantly higher, as expected, in the BMI> 25kg/m2 in comparison with the BMI25kg/m2 were also significantly higher compared with BMI< or =25kg/m2, HDL- cholesterol and adiponectin were significantly higher in BMI< or =25kg/m2. On multiple logistic regression analysis for the components of MS, exercise, adiponectin and leptin were an only independent factor for MS in non-obese male workers(BMI< or =25kg/m2) after adjustment for age, cigarette smoking and drinking habits. CONCLUSION: These results suggested that the obesity in men was associated with physiological levels of adiponectin and leptin contributing to feedback control of MS and that dysfunction and/or declination in feedback control system associated with changes in physiological levels of neurptrophics: adiponectin and leptin might ultimately induce MS.

Effects of Obesity on the Physiological Levels of Adiponectin, Leptin and Diagnostic Indices of Metabolic Syndrome in Male Workers / 산업간호학회지

PURPOSE: The aim of this study was to examine the effects of obesity on the physiological levels of adiponectin, leptin and components of metabolic syndrome (MS) in male workers, aged 30-40 years. METHODS: Body mass index (BMI) was measured with Anthropometric equipment. Blood pressure and serum parameters were measured with an automatic digital sphygmomanometer and autochemical analyzer, respectively. Adiponectin and leptin were analysed by ELISA kits and MS was defined based on the NCEP-ATP III. RESULTS: Body fat mass of waist and hip, systolic and diastolic blood pressure were significantly higher, as expected, in the BMI> 25kg/m2 in comparison with the BMI25kg/m2 were also significantly higher compared with BMI< or =25kg/m2, HDL- cholesterol and adiponectin were significantly higher in BMI< or =25kg/m2. On multiple logistic regression analysis for the components of MS, exercise, adiponectin and leptin were an only independent factor for MS in non-obese male workers(BMI< or =25kg/m2) after adjustment for age, cigarette smoking and drinking habits. CONCLUSION: These results suggested that the obesity in men was associated with physiological levels of adiponectin and leptin contributing to feedback control of MS and that dysfunction and/or declination in feedback control system associated with changes in physiological levels of neurptrophics: adiponectin and leptin might ultimately induce MS.

Acoustic Calibration of Clinical Audiometers Used for Special Periodic Health Examination / 대한산업의학회지

OBJECTIVES: Various problems are encountered during audiometric testing. Deviation from reference threshold levels for supra-aural earphones is often a serious problem when hearing levels are measured. This paper reports the acoustic calibration of clinical audiometers used for special periodic health examination. METHODS: ANSI S3.6-1996 Specification for Audiometers represents our most current and best resource for information regarding audiometers. The acoustic calibration was measured in 211 clinical audiometers and compared with the ANSI S3.6-1996 reference threshold levels for supra-aural earphones. RESULTS: Among 211 clinical audiometers, 56 (26.5%) exceeded the permitted deviation from reference threshold levels at any test frequency in ANSI S3.6-1996 for left supra-aural earphones, and 54 (25.6%) for right. An exhaustive calibration was required for 16 audiometers (7.6%) in both supra-aural earphones. The absolute difference in dB deviation from reference threshold levels by performed acoustic calibration at least annually were statistically significant at any test frequency (p<.05). CONCLUSIONS: The results of this study strongly indicate that clinical audiometry is being conducted with pure-tone audiometers having unallowable sound pressure levels deviations for supra-aural earphones. The validity of audiometric hearing thresholds are significantly affected by these deviations from the acoustic calibration levels of audiometers. Therefore audiometer calibration need to be checked functionally daily and acoustically at least annually.

Ambient Noise Levels in the Audiometric Test Rooms Used for Special Periodic Health Examination / 대한산업의학회지

OBJECTIVES: The ambient noise levels in the test rooms affect the workers's hearing threshold. The present study was designed to assess the ambient noise levels in the test rooms to determine if valid hearing tests, both pure-tone air conduction and bone-conduction, could be performed in these environments. METHODS: In the present study, third octave band ambient noise sound pressure levels were measured in 124 audiometric test rooms used for clinical audiometry, and the results were compared with the ANSI third octave band maximum permissible ambient noise levels (MPANLs) for each test condition and frequency range. RESULTS: The ambient noise SPLs were highest in the lower frequencies, and this decreased as the frequency increased. For the "ears covered"condition, about 24.2% of the rooms were in compliance (pass) with the MPANLs for the 125-8000 Hz, 35.5% were in compliance for the 250-8000 Hz range and 55.6% were in compliance for the 500-8000 Hz range. For the "ears not covered"condition, only about 8.1% of the rooms passed for the 125-8000 Hz, 13.7% of the rooms passed for the 250-8000 Hz range and 34.7% of the rooms passed for the 500-8000 Hz range. All 124 rooms met the OSHA MPANLs. CONCLUSIONS: The results of this study strongly indicate that clinical audiometry is being conducted in test rooms having unacceptable or excessive ambient noise levels.