Reconstruction of the Korean Asbestos Job Exposure Matrix

Background@#A job-exposure matrix (JEM) is an important surrogate indicator to evaluate past exposure levels. Although a Korean asbestos JEM has been constructed previously, this JEM includes only a few industrial and occupational groups. This study aimed to reconstruct the JEM by integrating the latest organized data to improve its utility. @*Methods@#We used recent Korean standard industry and occupation codes and extracted 36 articles from a systematic literature review to initiate the reconstruction of the previous Korean asbestos JEM. The resulting data consisted of 141 combinations of industrial and occupational groups. Data from the Netherlands's JEM were also reviewed and categorized into 70 industrial and 117 occupational groups by matching with the Korean data. We also utilized Germany's data, which consisted of 10 industrial and 14 occupational groups. @*Results@#The reconstructed Korean asbestos JEM had 141 combinations of industries and occupations. The time periods are from the 1980s to the 2000s in 10-year intervals. Most of the data were distributed between the 1990s and the 2000s. Occupations with high exposure to asbestos included knitting and weaving machine operators, automobile mechanics or assemblers, ship mechanics or assemblers, mineral ore and stone products processing mechanics, and metal casting machine operators or mold makers. @*Conclusions@#The reconstructed Korean asbestos JEM has expanded the type and duration of the occupational groups of the previous JEM and can serve as an important reference tool for evaluating asbestos exposure and designing compensation and prevention policies in Korea.

Reconstruction of the Korean Asbestos Job Exposure Matrix

Background@#A job-exposure matrix (JEM) is an important surrogate indicator to evaluate past exposure levels. Although a Korean asbestos JEM has been constructed previously, this JEM includes only a few industrial and occupational groups. This study aimed to reconstruct the JEM by integrating the latest organized data to improve its utility. @*Methods@#We used recent Korean standard industry and occupation codes and extracted 36 articles from a systematic literature review to initiate the reconstruction of the previous Korean asbestos JEM. The resulting data consisted of 141 combinations of industrial and occupational groups. Data from the Netherlands's JEM were also reviewed and categorized into 70 industrial and 117 occupational groups by matching with the Korean data. We also utilized Germany's data, which consisted of 10 industrial and 14 occupational groups. @*Results@#The reconstructed Korean asbestos JEM had 141 combinations of industries and occupations. The time periods are from the 1980s to the 2000s in 10-year intervals. Most of the data were distributed between the 1990s and the 2000s. Occupations with high exposure to asbestos included knitting and weaving machine operators, automobile mechanics or assemblers, ship mechanics or assemblers, mineral ore and stone products processing mechanics, and metal casting machine operators or mold makers. @*Conclusions@#The reconstructed Korean asbestos JEM has expanded the type and duration of the occupational groups of the previous JEM and can serve as an important reference tool for evaluating asbestos exposure and designing compensation and prevention policies in Korea.

Distribution of working position among workers with varicose veins based on the National Health Insurance and National Employment Insurance data

Background@#This study aimed to determine the effect of specific working postures on the development of varicose veins (VV). By using Korea's National Health Insurance (NHI) and National Employment Insurance (NEI) data, we analyzed the general characteristic and difference in proportions of VV cases according to occupational working posture. @*Methods@#From the NEI and NHI data, participant demographics, such as gender, age, body mass index, and number of workers in specific occupations or industries were obtained.We classified the 240 occupations into blue-collar (BC) and white-collar (WC) occupations and subdivided them into standing, sitting, and walking groups according to the dominant working posture. @*Results@#The number of VV patients per 100,000 individuals increased with age, with a higher number of women than men and a higher number of patients in the BC than WC groups. For the BC group, the proportion of VV cases was the highest in the standing group, followed by the walking and sitting groups, but there was no significant difference between standing and walking groups in man. For the WC group, the standing group had a higher proportion of VV cases than the sitting group, but there was no significant difference between the standing and sitting group in man. In the BC group, the proportion of VV cases was the highest among medical and welfare-related elementary workers, bakers and cookie makers, automobile assemblers, cleaning and guarding-related elemental workers, and nurses and dental hygienists. In the WC group, the proportion of VV cases was the highest among food/ lodging/tourism/entertainment/sports-related managers, environment/cleaning/protective services-related managers, finance and insurance clerks, accounting book-keeping clerks, and social welfare and counseling professionals. @*Conclusions@#This study was performed to determine the characteristics of VV with different working posture among Korean workers. It is expected to be the basis of further studies on occupational musculoskeletal diseases.

Distribution of working position among workers with varicose veins based on the National Health Insurance and National Employment Insurance data

Background@#This study aimed to determine the effect of specific working postures on the development of varicose veins (VV). By using Korea's National Health Insurance (NHI) and National Employment Insurance (NEI) data, we analyzed the general characteristic and difference in proportions of VV cases according to occupational working posture. @*Methods@#From the NEI and NHI data, participant demographics, such as gender, age, body mass index, and number of workers in specific occupations or industries were obtained.We classified the 240 occupations into blue-collar (BC) and white-collar (WC) occupations and subdivided them into standing, sitting, and walking groups according to the dominant working posture. @*Results@#The number of VV patients per 100,000 individuals increased with age, with a higher number of women than men and a higher number of patients in the BC than WC groups. For the BC group, the proportion of VV cases was the highest in the standing group, followed by the walking and sitting groups, but there was no significant difference between standing and walking groups in man. For the WC group, the standing group had a higher proportion of VV cases than the sitting group, but there was no significant difference between the standing and sitting group in man. In the BC group, the proportion of VV cases was the highest among medical and welfare-related elementary workers, bakers and cookie makers, automobile assemblers, cleaning and guarding-related elemental workers, and nurses and dental hygienists. In the WC group, the proportion of VV cases was the highest among food/ lodging/tourism/entertainment/sports-related managers, environment/cleaning/protective services-related managers, finance and insurance clerks, accounting book-keeping clerks, and social welfare and counseling professionals. @*Conclusions@#This study was performed to determine the characteristics of VV with different working posture among Korean workers. It is expected to be the basis of further studies on occupational musculoskeletal diseases.

Comparison of facet joint degeneration in firefighters and hospital office workers

BACKGROUND: There are few published studies on the relationship between occupational lumbar load and facet joint degeneration (FJD). This cross-sectional study was conducted to evaluate the effect of physical lumbar load on FJD by comparing magnetic resonance imaging (MRI) findings of firefighters (FFs) and hospital office workers (HOWs). METHODS: We randomly sampled 341 male FFs and 80 male HOWs by age stratification. A questionnaire and clinical examination, including MRI of the lumbar spine (T12-S1), were conducted. FJD was diagnosed and graded by using the classification of Pathria et al., and reclassified into two groups as follows: no FJD (grade 0) and FJD (grades 1, 2, and 3). The prevalence of FJD was analyzed according to occupational group. RESULTS: The prevalence of FJD ranged from 31% (L1–L2) to 75% (L4–L5) in the FFs, and from 18% (L1–L2) to 69% (L4–L5) in the HOWs. After adjustment for age, body mass index, and frequency of physical exercise, the adjusted odds ratios (OR) for FJD in the FFs were significantly higher than those in the HOWs at all lumbar spinal levels, except for L3–L4 (L1–L2: OR, 2.644; 95% confidence interval [CI], 1.317–5.310; L2–L3: OR, 2.285; 95% CI, 1.304–4.006; L4–L5: OR, 1.918; 95% CI, 1.037–3.544; L5–S1: OR, 1.811; 95% CI, 1.031–3.181). CONCLUSION: This study shows that FFs exhibit a greater likelihood of having FJD than HOWs after controlling for other risk factors of FJD. This suggests that the physical occupational demands of FFs affect their risk of developing FJD.

Effects of high occupational physical activity, aging, and exercise on heart rate variability among male workers

OBJECTIVES: Effects of aging and leisure time physical activity (LPA) might influence the effect of occupational physical activity (OPA) on risk for cardiovascular disease (CVD). This study was conducted to determine whether OPA affects CVD after controlling the effects of LPA and other risk factors for CVD such as job stress. METHODS: Participants were 131 male Korean manual workers. Tests for heart rate variability (HRV) were conducted for five minutes in the morning at work. We defined OPA as the combined concept of relative heart rate ratio (RHR), evaluated using a heart rate monitor. RESULTS: Whereas high OPA was not related to any HRV items in the younger age group, high OPA was associated with an increased number of low-value cases among all HRV items in older workers. Exercise had beneficial effects only in the younger group. After controlling for exercise and other risk factors, the odds ratios of the root-mean square of the difference of successive normal R-R intervals (rMSSD) and high frequency band power (HF) among the older age and high OPA group compared with the younger age and low OPA group were 64.0 and 18.5, respectively. Social support and shift work were independent risk factors in HRV. CONCLUSIONS: OPA in aging workers increases CVD risks. This study provides support for the need for protection of aging workers from physical work overload, and indicates the need for further study of optimal limits of OPA.

Work-related Musculoskeletal Disorders in Korea Provoked by Workers' Collective Compensation Claims against Work Intensification

This article presents the process of workers' problems with work related musculoskeletal disorders (WMSDs), the introduction of risk assessments (RA) for their prevention, and the consequences of this process in Korea. In 1997, economic crisis caused a rapid increase of massive layoffs, worker dispatch system introduction, job insecurity, and use of irregular workers resulting in work intensification. Work intensification increased WMSDs, which created massive workers' compensation collective claims. Workers argued for the reduction of work intensity. The RAs introduced as a consequence of the workers' struggle is unique in the world. Whereas these RAs were expected to play a pivotal role in WMSDs prevention, they dis not due to workers' lack of engagement after the compensation struggle. In fact, changes in the compensation judgment system and criteria have resulted in lower compensation approval rates leading to lower workers' compensation claims. The Korean experience provides insight into WMSDs causes in a globalized world. In such a the globalized world, work intensification as the result of work flexibility could be an international trend.

Relationship of Glomerular Basement Membrane Alterations to Epithelial Cell Structure and Clinical Parameters in Alport Syndrome

PURPOSE: This study was performed to evaluate the relationship between glomerular basement membrane (GBM) alterations to epithelial cell (EpC) structure and renal function in Alport Syndrome (AS) patients. METHODS: Fifteen patients diagnosed with AS (4-26yrs) were examined. The GBM in AS was categorized as: C1) normal, C2) minor alterations (widening of lamina rara interna or externa without lamina densa change), C3) nonspecific splitting of lamina densa, C4) basket-weaving pattern of lamina densa splitting. The length of each GBM portion along the epithelial side was measured on the systematically obtained electron microscopic photographs. Furthermore to obtain an objective assessment of the degree of glomerular EpC foot process change, the number of slit pores along 10 microm of peripheral GBM in each category was obtained. RESULTS: The percentage of normal GBM portion (C1) correlated inversely with daily protein excretion (g/day/m2, P <0.05) and sum of the percentage of abnormal GBM portion (C2+C3+C4) had direct correlation with daily protein excretion (g/day/m2, P <0.05). There were no significant relationships between the percentages of other categories of GBM alterations and creatinine clearance or protein excretion. There were no significant relationships between of creatinine clearance in relation to normal GBM(C1) portion as well as that in relation to sum of the percentage of abnormal GBM portion (C2+C3+C4). GBM abnormality did not correlate with age at biopsy. CONCLUSION: The extent of GBM structural abnormality is related to proteinuria in AS but the epithelial response is uniform even though the GBM ultrastructural lesions are not.

Respiratory Symptoms, Pulmonary Function Tests, and Asbestos Related Chest Radiograph Abnormalities of Former Asbestos Textile Factory Workers / 대한산업의학회지

OBJECTIVES: The objective of this study was to examine the prevalence of respiratory symptoms, asbestos-related chest radiograph abnormalities and abnormal pulmonary function tests among former asbestos textile factory workers and to reveal the related factors of these abnormal findings. METHODS: There were 119 persons former asbestos textile industry workers registered in the health management pocketbook. Of 97 retired asbestos workers living in Busan, Yangsan and Gimhae, 63(64.9%) retired asbestos workers were enrolled into this study. The researchers administered questionnaires, and performed chest radiographys, and pulmonary function tests (PFT) on participants. The survey was conducted during July, 2009. RESULTS: Among former workers the number of lung fibrosis, pleural plaque, pleural calcification, and pleural thickening was 13(20.6%), 6(9.5%), 3(4.8%), and 1(1.6%) in chest radiography, respectively. Asbestos-related disorders and abnormal pulmonary function test groups had higher prevalence of respiratory symptoms. Participants with crocidolite exposure or long latency period had higher asbestos-related x-ray findings or abnormal PFT findings. CONCLUSIONS: Former asbestos textile workers had a high rate of asbestos-related disorders. Workers with crocidolite exposure or having had a longer latency period had more asbestos-related disorders. Because gradual increase of asbestos related disorders among high asbestos exposure group is expected, sustained, and intensive management is needed for these former workers.

Chronic and Acute Effects of Work-related Factors on Heart Rate Variability / 대한산업의학회지

OBJECTIVES: Reduced heart rate variability (HRV) is one of the serious risk factors for heart diseases. We evaluated the acute and chronic effects of work-related factors on HRV. METHODS: The five-minute HRV of 85 male workers from an automobile assembly factory were measured at 9 A.M. (before-work) and at 5 P.M. (after-work). The workplace noise, temperature and physical workload levels were measured as work-related factors. We postulated that the HRV measured at beforework represents the chronic effects and the HRV measured at after-work represents the acute effects of work-related factors. We used generalized linear regression analysis with adjusting for the general characteristics and/or the morning HRV. RESULTS: The subjects exposed to noise or a hot environment showed increased HRV in the afternoon and decreased HRV in the morning. Machine oil and interpersonal conflict decreased the HRV in the morning, but other chemicals did not show any effect on the HRV. A physical workload decreased the HRV in both the morning and afternoon. CONCLUSION: The physical and chemical environment, psychosocial stress and a physical workload may affect the autonomic nerve system.

The Relationship between Work Ability and Job Stress Factors in Manufacturing Industries / 대한산업의학회지

OBJECTIVE: This study was performed to investigate the association between work ability and job stress factors in three manufacturing industries. METHODS: The data were gathered from 705 workers of 3 manufacturing industries, from August 2007 to January 2008. A structured, self-reported questionnaire was used to access the demographic, socioeconomic and work related characteristics. Work ability and job stress factors were determined using two questionnaires: the work ability index (WAI) of the Finnish Institute of Occupational Health and the Korean Occupational Stress Scale (KOSS), respectively. RESULTS: According to the logistic regression analysis results, WAI was related to job stress factors after adjustment for age, shift work, employment type and exercise. Of the eight subscales, job demand, interpersonal conflict, lack of reward, occupational climate and total score were significantly associated with WAI. In the analysis of each factory, interpersonal conflict, job insecurity and lack of reward were significantly associated with WAI in factory II, and organizational system, lack of reward and total score in factory III, but there was no significant association in factory I. CONCLUSIONS: Job stress factors were significantly associated with WAI in two of the three manufacturing industries. Further and more detailed study needs to be conducted to reduce the job stress and improve the work ability.

Difference in Severity of Acute Rejection Grading between Superfical Cortex and Deep Cortex in Renal Allograft Biopsies

Twenty-six renal allograft biopsies which showed acute rejection and had renal capsule and medulla in the same specimen were selected in order to compare the severity of acute rejection between superficial cortex, deep cortex and medulla. Disregarding the mid cortical region, the superficial cortex was considered as being one-third of the distance from the renal capsule to the medulla and the deep cortex as being that one-third of the cortex which was adjacent to the medulla. Using semiquantitative histologic analysis the following parameters were compared in superficial cortex, deep cortex, and medulla: interstitial inflammation, edema, tubulitis, and acute tubulointerstitial rejection grade. Also, the presence of lymphocyte activation and polymorphonuclear leukocytes was evaluated. Significantly greater histologic changes of acute rejection were found in the deep cortex vs. superficial cortex for the following parameters: interstitial inflammation(P=0.013), edema (P= 0.023) and tubulointerstitial rejection grade(P=0.016). These findings support the view that biopsies in which deep cortex is not included may result in underestimation of the severity of renal allograft rejection.

Dose-Response Relationships between Work-Related Musculoskeletal Neck Symptom and Physical Risk Factors (2 year follow-up study) / 대한산업의학회지

OBJECTIVES: To estimate the association of work-related musculoskeletal neck symptom and occupational risk factors, and to identify the dose-response relationships between work-related musculoskeletal neck symptom and physical condition. METHODS: Workers from four metal industry companies were enrolled in the study. General characteristics, psyhcosocial and physical risk factors and work-related musculoskeletal neck symptom were investigated by questionnaire in the baseline study. At the follow-up study 2 years later, the neck symptom was surveyed. Workers who did not complain neck symptom at baseline and complain at follow-up, and workers who did complain neck symptom at baseline and follow-up were defined as case. The adjusted odds ratios (ORs) of physical risk factors were estimated for these subjects. Additionally, subjects who did not change their work at follow-up were analysed. RESULTS: Among the cohort of 251, 199 (79.3%) were used in the analysis, of which 71 (35.7%) were classified as cases. The adjusted ORs and the ORs of the subjects who did not change their work were increased with exposure to the following kinds of work: 'repetitive', 'lift', 'push/pull', 'neck/shoulder (overhead/bend)', 'hand/wrist (bend/pinch)', 'trunk (twist/bend)', 'pressure point', and 'incentive work'. Finally, with increasing exposure to 'repetitive', 'lift', 'push/pull', 'awkward postures', 'pressure point', and 'incentive work', the risks of work-related musculoskeletal neck symptom were increased. CONCLUSIONS: Work-related musculoskeletal neck symptom was increased with increasing exposure time of certain physical risk factors, and a dose-response relationship was observed.