Acute toxic encephalopathy induced by occupational exposure to 1,2-dichloropropane.

1,2-Dichloropropane (1,2-DCP) is used widely in Korea as a substitute for trichloroethylene or methylene chloride. Some companies mistakenly consider that 1,2-DCP is an eco-friendly detergent because its use is not regulated, but 1,2-DCP is known to inhibit the central nervous system in animals; a few cases of accidental exposure have been reported in humans. We present a case of acute encephalopathy caused by exposure to 1,2-DCP. A 41 yr-old male presented with dizziness, headache, and diplopia after exposure to the detergent without protective equipment. Brain magnetic resonance imaging suggested metabolic encephalopathy, but the patient had no thiamine deficiency and no other metabolic disorder. As the symptoms had commenced after exposure to a large amount of solvent while skimming rust from the surface, and as the symptoms were more severe during the work week, improved on weekends, and disappeared after solvent exposure ceased, the toxic encephalopathy was likely induced by inhalation of the detergent.

Association between serum ferritin and hypertension according to the working type in Korean men: the fifth Korean National Health and nutrition examination survey 2010-2012.

BACKGROUND: Several studies suggest that serum ferritin concentrations reflect systemic inflammation, and high ferritin levels can increase the risk of hypertension in adult men. Shift work is also known to increase the risk of hypertension; however, there has been no study about the relationship between serum ferritin levels and the prevalence of hypertension according to the working type. METHODS: This cross-sectional study included 4,442 male participants (3,651 daytime workers and 791 shift workers) who participated in the fifth Korean National Health and Nutrition Examination Survey. Hypertension was defined as a systolic blood pressure greater than or equal to 140 mmHg, a diastolic blood pressure greater than or equal to 90 mmHg or the current use of antihypertensive medications regardless of blood pressure values. For the statistical analyses, serum ferritin levels were reclassified into quartiles, and complex sample analyses were used to evaluate the relationship between serum ferritin levels and the prevalence of hypertension according to the working type in this study. RESULTS: Serum ferritin and shift work were positively associated with the prevalence of hypertension. The effect of interaction was above multiplicative. When compared to participants in the lowest serum ferritin quartile, the odds ratio for hypertension for participants in the highest serum ferritin quartile was 1.372 (1.027-1.833) in daytime workers and 2.009 (1.042-3.873) in shift workers after adjustment. CONCLUSIONS: The prevalence of hypertension increased as ferritin levels increased in individuals, especially in shift workers.

The Asbestos Ban in Korea from a Grassroots Perspective: Why Did It Occur?

In 2009, asbestos was finally banned in Korea, about 70 years after the first opening of asbestos mines under Japanese control. After having presented the history of asbestos industry, together with its regulations and health effects over time, we constructed narrative analyses of how the asbestos issue under the prevailing risk system was managed by whom and for what purpose, to provide context for the change. We could identify five different phases: laissez-faire, politico-technical, economic-managerial, health-oriented cultural, and human rights-based post-cultural risk systems. The changes leading to the asbestos ban evolved over different phases, and each phase change was necessary to reach the final ban, in that, without resolving the previous issues by examining different categories of potential alternatives, either the final ban was not possible or, even if instituted, could not be sustained. An asbestos ban could be introduced when all the alternatives to these issues, including legitimate political windows, economic rationalizations, health risk protections, and human rights sensitivities, were available. We think the alternatives that we had were not in perfect shape, but in more or less loosely connected forms, and hence we had to know how to build solidarities between different stakeholders to compensate for the imperfections.

Reticulocytosis in screen-printing workers exposed to 2-butoxyethanol and 2-ethoxyethanol.

BACKGROUND: Studies on the hematologic toxicity of ethylene glycol ethers in humans are limited. Therefore, the aim of this study was to examine the association between exposure to solvents (containing 2-butoxyethanol and 2-ethoxyethanol) and hematological effects. METHODS: Thirty-four screen-printing workers who were exposed to 2-butoxyethanol and 2-ethoxyethanol and 37 non-exposed clerical workers were selected using data from the health care facilities that provided regular health screening services. Student's t-tests and Pearson's chi-square tests were used to compare differences in hematological parameters between the exposed and the control groups. A multivariate analysis was performed using the multiple logistic regression models to adjust for other variables. RESULTS: The chi-square test showed the reticulocyte percentages and corrected reticulocyte counts to be significantly higher in the exposed group. The t-tests showed a significant increase in white blood cell counts, reticulocyte percentages, and corrected reticulocyte count (i.e., reticulocyte index) in the exposed group, with p-values of 0.002, 0.004, and 0.002, respectively. Multivariate analysis showed the odds ratio for the corrected reticulocyte counts to be 16.30 for the exposed group, when compared with that of the control group. CONCLUSIONS: Exposure to 2-butoxyethanol and 2-ethoxyethanol was significantly associated with reticulocytosis, necessitating the implementation of preventive measures for workers prone to occupational exposure to ethylene glycol ethers.

Estimated future incidence of malignant mesothelioma in South Korea: Projection from 2014 to 2033.

Malignant mesothelioma is a malignant tumor on the pleura or the peritoneum caused mostly by asbestos. Although asbestos is not currently used in South Korea, the incidence of mesothelioma is increasing due to its long latent period. This study predicted the incidence of malignant mesothelioma in South Korea over the next 20 years using an age-period-cohort (APC) model. Data regarding mesothelioma incidence from 1994-2013 were acquired from the Korea Central Cancer Registry (KCCR). Demographic data, including prospective resident data, were acquired from the Korean Statistical Information Service (KOSIS) for 1994-2033. An APC model with Møller's power-link function was utilized to predict the incidence of mesothelioma. It was predicted that 2,380 and 1,199 new cases of mesothelioma in men and women, respectively, would occur over the next 20 years. For both sexes, the mesothelioma incidence rate was predicted to be greater in 2029-2033 compared to that in 2009-2013 (men, 0.282 vs 0.563; women, 0.155 vs 0.217). For men, the age-standardized incidence rate was predicted to be slightly greater in 2029-2033 relative to the rate in 2009-2013 (0.228 vs 0.235), while the age-standardized incidence rate in women decreased within the same timeframe (0.113 vs 0.109). The changes in mesothelioma incidence were mostly caused by changes in the population structure due to aging and not by changes in the mesothelioma risk ratio. The results of this study project a continuous increase in mesothelioma incidence in South Korea over the next 20 years. Although the projected increase in mesothelioma incidence was not related to an increase in the mesothelioma risk ratio, continuous preventive efforts are necessary to reduce the exposure to asbestos and prevent the trend from worsening.

Comparison of the long-term efficacy between entecavir and tenofovir in treatment- naïve chronic hepatitis B patients.

BACKGROUND: There have been limited studies directly comparing the long-term efficacy between entecavir (ETV) and tenofovir disoproxil fumarate (TDF). This study was aimed to compare the long-term efficacy between them in treatment-naïve chronic hepatitis B (CHB). METHODS: Out of 345 CHB patients who received first line therapy with ETV (n = 200) or TDF (n = 145) in a cohort, 210 patients were analyzed using propensity score matching, at a ratio of 1:1. RESULTS: Two groups showed no difference in baseline characteristics. During the follow-up of 12 months, HBV DNA levels were similarly suppressed in both groups (ETV vs. TDF; -5.01 vs. -5.242 log10IU/mL, P = 0.559). At month 12, both groups showed no difference in terms of the serologic, biochemical and virologic (VR) response. In multivariate analysis, the initial virologic response at 3 months (IVR-3) was independent factor for VR at 1 year. During the long-term follow-up, HBV DNA levels were more strongly suppressed by TDF than ETV in hepatitis B e antigen (HBeAg) positive patients (P = 0.035), especially with high viral load (P = 0.012), although there was no significant difference in overall VR between two groups. The type of antivirals was not an independent factor for long-term VR. CONCLUSIONS: Although either ETV or TDF, overall, may show a comparable long-term antiviral efficacy in treatment-naïve CHB, TDF might be better regimen than ETV in the subgroup of HBeAg-positive CHB, especially with a higher HBV DNA levels.

The effect of aircraft noise on sleep disturbance among the residents near a civilian airport: a cross-sectional study.

BACKGROUND: Aircraft noise is a major environmental noise problem. This study was conducted in order to investigate the relationship between sleep disturbance and exposure to aircraft noise on the residents who are living near an airport. METHODS: There were 3308 residents (1403 in the high exposure group, 1428 in the low exposure group, and 477 in the non-exposure group) selected as the subjects for this study. The Insomnia severity Index (ISI) and Epworth Sleepiness Scale (ESS) questionnaires were used to evaluate sleep disturbance. RESULTS: The mean ISI and ESS scores were 6.9 ± 6.4 and 5.5 ± 3.7, respectively, and the average scores were significantly greater in the aircraft noise exposure group, as compared to the non-exposure group. The percentage of the abnormal subjects, which were classified according to the results of the ISI and ESS, was also significantly greater in the noise exposure group, as compared to the control group. The odd ratios for insomnia and daytime hypersomnia were approximately 3 times higher in the noise exposure group, as compared to the control group. CONCLUSIONS: The prevalence of insomnia and daytime hypersomnia was higher in the aircraft noise exposure group, as compared to the control group. Further study is deemed necessary in order to clarify the causal relationship.

Carbon monoxide poisoning-induced cardiomyopathy from charcoal at a barbecue restaurant: a case report.

OBJECTIVE: Acute carbon monoxide poisoning has important clinical value because it can cause severe adverse cardiovascular effects and sudden death. Acute carbon monoxide poisoning due to charcoal is well reported worldwide, and increased use of charcoal in the restaurant industry raises concern for an increase in occupational health problems. We present a case of carbon monoxide poisoning induced cardiomyopathy in a 47-year-old restaurant worker. MATERIALS AND METHODS: A male patient was brought to the emergency department to syncope and complained of left chest pain. Cardiac angiography and electrocardiography were performed to rule out acute ischemic heart disease, and cardiac markers were checked. After relief of the symptoms and stabilization of the cardiac markers, the patient was discharged without any complications. RESULTS: Electrocardiography was normal, but cardiac angiography showed up to a 40% midsegmental stenosis of the right coronary artery with thrombotic plaque. The level of cardiac markers was elevated at least 5 to 10 times higher than the normal value, and the carboxyhemoglobin concentration was 35% measured at one hour after syncope. Following the diagnosis of acute carbon monoxide poisoning induced cardiomyopathy, the patient's medical history and work exposure history were examined. He was found to have been exposed to burning charcoal constantly during his work hours. CONCLUSIONS: Severe exposure to carbon monoxide was evident in the patient because of high carboxyhemoglobin concentration and highly elevated cardiac enzymes. We concluded that this exposure led to subsequent cardiac injury. He was diagnosed with acute carbon monoxide poisoning-induced cardiomyopathy due to an unsafe working environment. According to the results, the risk of exposure to noxious chemicals such as carbon monoxide by workers in the food service industry is potentially high, and workers in this sector should be educated and monitored by the occupational health service to prevent adverse effects.

Differentiation of acute and chronic hepatitis B in IgM anti-HBc positive patients.

AIM: To identify the factors that differentiate acute hepatitis B (AHB) from chronic hepatitis B with acute exacerbation (CHB-AE). METHODS: From 2004 to 2013, a total of 82 patients (male n = 52, 63.4%; female n = 30, 36.6%) with clinical features of acute hepatitis with immunoglobulin M antibodies to the hepatitis B core antigen (IgM anti-HBc) were retrospectively enrolled and divided into two groups; AHB (n = 53) and CHB-AE (n = 29). The AHB group was defined as patients without a history of hepatitis B virus (HBV) infection before the episode and with loss of hepatitis B surface antigen within 6 mo after onset of acute hepatitis. Biochemical and virological profiles and the sample/cutoff (S/CO) ratio of IgM anti-HBc were compared to determine the differential diagnostic factors. RESULTS: The multivariate analysis demonstrated that, the S/CO ratio of IgM anti-HBc and HBV DNA levels were meaningful factors. The S/CO ratio of IgM anti-HBc was significantly higher in the AHB group, while the HBV DNA level was significantly higher in the CHB-AE group. The optimal cutoff values of IgM anti-HBc and HBV DNA levels for differentiating the two conditions were 8 S/CO ratio and 5.5 log10 IU/mL, respectively. The sensitivity and specificity were 96.2% and 89.7% for the S/CO ratio of IgM anti-HBc and 81.1% and 72.4% for HBV DNA levels, respectively. The area under receiver operating characteristic curves of both the S/CO ratio of IgM anti-HBc and HBV DNA levels were not significantly different (0.933 vs 0.844, P = 0.105). When combining IgM anti-HBc and HBV DNA, the diagnostic power significantly improved compared to HBV DNA alone (P = 0.0056). The combination of these factors yielded a sensitivity and specificity of 98.1% and 86.2%, respectively. CONCLUSION: The combination of the S/CO ratio of IgM anti-HBc and HBV DNA levels was a useful tool for differentiating AHB from CHB-AE in patients with positive IgM anti-HBc.

The effect of organisational system on self-rated depression in a panel of male municipal firefighters.

OBJECTIVES: The present study evaluated the effects of job stress, including organisational system to self-rated depression through a panel study of male municipal firefighters in the Republic of Korea. METHODS: A panel of 186 municipal firefighters reported self-rated depressive symptoms according to the Beck Depression Inventory (BDI). The effects of job stress were evaluated using the Korea Occupational Stress Scale, taken one year earlier and classified by the median value. Panel members were classified into Depression or Control groups according to BDI scores, with a cut-off level of 'over mild depression' in a follow-up survey. RESULTS: The Depression group included 17 (9.1%) workers. Firefighters who scored high on occupational system had an 8.3 times greater risk of being assigned to the Depression group than those who had not (adjusted odds ratio [OR] = 8.03, 95% confidence interval (CI) = [1.73-37.22]). In contrast, job stress from a 'difficult physical environment' revealed negative risks related to being classified in the Depression group (AOR = 0.20, 95% CI = [0.04-0.92]). CONCLUSIONS: Although the healthy worker effect may be involved, job stress based on perceptions of organisational system was a strong risk factor for depression. A comprehensive approach should be considered that encompasses social issues when assessing or mental health in high-risk groups, as well as the practical issue of physiochemical hazards.