Jungsun Park

Cancer Mortality and Incidence in Korean Semiconductor Workers

Objectives The purpose of this study was to evaluate cancer risks in the Korean semiconductor industry. Methods A retrospective cohort study was performed in eight semiconductor factories between 1998 and 2008. The number of subjects was 113,443 for mortality and 108,443 for incidence. Standardized mortality ratios (SMR) and standardized incidence ratios (SIR) were calculated. Results The SMR of leukemia was 0.39 (95% Confidence Interval 0.08-1.14) in males (2 cases) and 1.37 (0.55-2.81) in females (7 cases). The SMR of non-Hodgkins lymphoma (NHL) was 1.33 (0.43-3.09, 5 cases) in males and 2.5 (0.68-6.40, 4 cases) in females. The SIR of leukemia was 0.69 (0.30-1.37, 8 cases) in males and 1.28 (0.61-2.36, 10 cases) in females. The SIR of NHL in females was 2.31 (1.23-3.95, 13 cases) and that of thyroid cancer in males was 2.11 (1.49-2.89, 38 cases). The excess incidence of NHL was significant in female assembly operators [SIR=3.15 (1.02-7.36, 5 cases)], but not significant in fabrication workers. The SIR of NHL in the group working for 1-5 years was higher than the SIR of NHL for those working for more than five years. The excess incidence of male thyroid cancer was observed in both office and manufacturing workers. Conclusion There was no significant increase of leukemia in the Korean semiconductor industry. However, the incidence of NHL in females and thyroid cancer in males were significantly increased even though there was no definite association between work and those diseases in subgroup analysis according to work duration. This result should be interpreted cautiously, because the majority of the cohort was young and the number of cases was small.

The Validity and Reliability of the Second Korean Working Conditions Survey

Background The aim of this study was to evaluate the quality of the Second Korean Working Conditions Survey (KWCS), focusing on its validity and reliability. Methods The external validity was evaluated by the assessment of sampling procedures and the response rate, in order to investigate the representativeness of the sample. The content validity was evaluated by the assessment of the development of the questionnaire, and the consistency of questions for the selected construct. The test-retest method was used to evaluate the reliability by means of a phone call survey of 30% of the respondents, who were randomly selected. The respondents satisfaction regarding the survey procedures and interview time were analyzed to evaluate the quality of survey data. Results The external validity was assured by an acceptable sampling procedure, rigid multi-stage stratified cluster random sampling. The content validity was also guaranteed by a reasonable procedure for the development of the questionnaire with a pretest. The internal consistency of the questions for work autonomy was maintained, with 0.738 of Cronbachs alpha. The response rate of 36% was lower than that of the European Working Conditions Survey (EWCS), with a contact rate of 66%, compared to 76% for the EWCS. The matching rates of the five retested questions were more than 98% reliable. Conclusion The quality of the second KWCS was assured by the high external and content validity and reliability. The rigid sampling procedure and development of the questionnaire contributed to quality assurance. The high level of reliability may be guaranteed by the sophisticated field survey procedures and the development of a technical manual for interviewers. The technical strategies for a high response rate should be developed for future surveys.

Hematopoietic and reproductive toxicity of 2-bromopropane, a recently introduced substitute for chlorofluorocarbons

2-Bromopropane and hydrochlorofluorocarbons (HCFCs), whose toxicity has scarcely been known, have recently been introduced as main substitutes for chlorofluorocarbons (CFCs). A major corporation in Korea replaced CFCs with 2-bromopropane and this actually led 23 Korean workers to be the worlds first 2-bromopropane intoxication victims. Out of 25 female workers in the tactile switch assembling section, 17 (68%) were diagnosed as having ovarian failure. Two affected female workers showed marked pancytopenia with markedly hypoplastic marrow. In the same section, two out of eight male workers showed azoospermia and four some degree of oligospermia. The above toxicity of 2-bromopropane was reproduced in experimental animal studies. Recently, health effects of HCFC 123, including toxic hepatitis, have been reported by several authors. The principle of replacement of toxic substances with non-toxic or less toxic chemicals is important in risk management, but substances still poorly known should not be confused with non-toxic or less toxic substances. Measures aimed at reducing exposure to chemicals with known toxicity rather than using new unknown alternatives may be a rational and effective approach to risk management.

Creating a Culture of Prevention in Occupational Safety and Health Practice

The incidence of occupational injuries and diseases associated with industrialization has declined markedly following developments in science and technology, such as engineering controls, protective equipment, safer machinery and processes, and greater adherence to regulations and labor inspections. Although the introduction of health and safety management systems has further decreased the incidence of occupational injuries and diseases, these systems are not effective unless accompanied by a positive safety culture in the workplace. The characteristics of work in the 21st century have given rise to new issues related to workers health, such as new types of work-related disorders, noncommunicable diseases, and inequality in the availability of occupational health services. Overcoming these new and emerging issues requires a culture of prevention at the national level. The present paper addresses: (1) how to change safety cultures in both theory and practice at the level of the workplace; and (2) the role of prevention culture at the national level.

The Magnitude of Mortality from Ischemic Heart Disease Attributed to Occupational Factors in Korea - Attributable Fraction Estimation Using Meta-analysis

Objectives Ischemic heart disease (IHD) is a major cause of death in Korea and known to result from several occupational factors. This study attempted to estimate the current magnitude of IHD mortality due to occupational factors in Korea. Methods After selecting occupational risk factors by literature investigation, we calculated attributable fractions (AFs) from relative risks and exposure data for each factor. Relative risks were estimated using meta-analysis based on published research. Exposure data were collected from the 2006 Survey of Korean Working Conditions. Finally, we estimated 2006 occupation-related IHD mortality. Results For the factors considered, we estimated the following relative risks: noise 1.06, environmental tobacco smoke 1.19 (men) and 1.22 (women), shift work 1.12, and low job control 1.15 (men) and 1.08 (women). Combined AFs of those factors in the IHD were estimated at 9.29% (0.3-18.51%) in men and 5.78% (-7.05-19.15%) in women. Based on these fractions, Koreas 2006 death toll from occupational IHD between the age of 15 and 69 was calculated at 353 in men (total 3,804) and 72 in women (total 1,246). Conclusion We estimated occupational IHD mortality of Korea with updated data and more relevant evidence. Despite the efforts to obtain reliable estimates, there were many assumptions and limitations that must be overcome. Future research based on more precise design and reliable evidence is required for more accurate estimates.

Outbreak of Sudden Cardiac Deaths in a Tire Manufacturing Facility: Can It Be Caused by Nanoparticles?

Objectives The purpose of this study was to review clinical characteristics and working environments of sudden cardiac death (SCD) cases associated with a tire manufacturer in Korea, and review possible occupational risk factors for cardiovascular disease including nanoparticles (ultrafine particles, UFPs). Methods We reviewed (i) the clinical course of SCD cases and (ii) occupational and non-occupational risk factors including chemicals, the physical work environment, and job characteristics. Results Possible occupational factors were chemicals, UFPs of rubber fume, a hot environment, shift work, overworking, and noise exposure. The mean diameter of rubber fume (63-73 nm) was (larger than diesel exhaust [12 nm] and outdoor dust [50 nm]). The concentration of carbon disulfide, carbon monoxide and styrene were lower than the limit of detection. Five SCD cases were exposed to shift work and overworking. Most of the cases had several non-occupational factors such as hypertension, overweight and smoking. Conclusion The diameter of rubber fume was larger than outdoor and the diesel exhaust, the most well known particulate having a causal relationship with cardiovascular disease. The possibility of a causal relation between UFPs of rubber fume and SCD was not supported in this study. However, it is necessary to continue studying the relationship between large sized UFPs and SCD.

Unexpected Natural Death among Korean Workers.

Unexpected Natural Death among Korean Workers: Jungsun Park, et al. Industrial Safety and Health Research Institute, Korea Industrial Safety Corporation—Even though workers deaths can be compensated for in Korea if work stress is substantiated as a cause, neither a definition nor a measure has been officially provided to verify occupational stress or overwork. This study was carried out to identify epidemiological characteristics and components of work stress associated with workers death. All the records of claims for compensation during 1994‐1995 were reviewed to select only the cases of natural death. A descriptive study on the characteristics of workers natural death and a matched case‐control study on stress components were carried out. Cerebrovascular accidents was the commonest cause of death (47.3%) in claims for compensation due to work stress, and coronary artery diseases took second place (29.9%). Sudden death occurring within 24 h after the attack comprised about 1/2 of the total cases. The attack took place most frequently at the workplace and most often during work. When work stress was classified and observed in four categories: sudden physical exertion, sudden psychologic excitement, prolongation of work time, and change in responsibility, only physical exertion within 24 h before the onset of symptoms proved to be significantly associated with workers unexpected natural death.

Long Working Hours in Korea: Based on the 2014 Korean Working Conditions Survey

Background Long working hours adversely affect worker safety and health. In 2004, Korea passed legislation that limited the work week to 40 hours, in an effort to improve quality-of-life and increase business competitiveness. This regulation was implemented in stages, first for large businesses and then for small businesses, from 2004 to 2011. We previously reported that average weekly working hours decreased from 2006 to 2010, based on the Korean Working Conditions Survey. Methods In the present study, we examine whether average weekly working hours continued to decrease in 2014 based on the 2014 Korean Working Conditions Survey. Results The results show that average weekly working hours among all groups of workers decreased in 2014 relative to previous years; however, self-employed individuals and employers (who are not covered by the new legislation) in the specific service sectors worked > 60 h/wk in 2014. Conclusion The Korean government should prohibit employees from working excessive hours and should also attempt to achieve social and public consensus regarding work time reduction to improve the safety, health, and quality-of-life of all citizens, including those who are employers and self-employed.

Vulnerability of employees in businesses with fewer than five workers (micro‐enterprises) to occupational safety and health problems

INTRODUCTIONnWe assessed the characteristics of micro-enterprises (businesses with fewer than five workers) focusing on occupational safety and health (OSH) issues.nnnMETHODSnWe performed a secondary analysis of data from the Economically Active Population Supplementary Survey and the fourth Korean Working Conditions Survey of 2014.nnnRESULTSnRelative to larger businesses, micro-enterprises employ more women, temporary workers, and older workers (>55 years). In addition, more workers in micro-enterprises held elementary occupations (unskilled or under-skilled) or sales and service jobs. Key sectors of such employment included the sectors of wholesale and retail trade and hotel and restaurants. Furthermore, lower skilled workers in such micro-enterprises more frequently reported exposure to ergonomic risk factors and subsequent musculoskeletal disorders, and they also experienced a much higher fatality rate due to occupational injuries.nnnCONCLUSIONnOur results indicate that Korean workers in micro-enterprises are more vulnerable to OSH problems than workers in larger businesses.

Gender differences in occupations and complaints of musculoskeletal symptoms: Representative sample of South Korean workers: Gender differences in occupations and complaints of musculoskeletal symptoms

INTRODUCTIONnThe present study examines gender differences in occupations, occupational hazards, and musculoskeletal symptoms in Korean workers.nnnMETHODSnWe performed a secondary analysis of data from the fourth Korean Working Conditions Survey (KWCS).nnnRESULTSnRelative to managers, men who were craft and related trades workers, equipment, machine operating and assembling workers, and in elementary occupations were more likely to report back pain (ORs: 2.08, 2.33, and 2.71, respectively); women who were skilled agricultural, forestry, and fishery workers were more likely to report back pain (OR: 3.96). Back pain was more likely to be reported in men exposed to carrying/moving heavy loads, painful/tiring postures, and repetitive hand/arm movements (ORs: 1.20, 2.26, and 1.28, respectively).nnnCONCLUSIONnMen and women workers differed in their reporting of ergonomic risk factors, and complaints of musculoskeletal symptoms. Am. J. Ind. Med. 60:342-349, 2017.