Typology of ROII Patterns on Cluster Analysis in Korean Enterprises

OBJECTIVES: Authors investigated the pattern of the rate of occupational injuries and illnesses (ROII) at the level of enterprises in order to build a network for exchange of experience and knowledge, which would contribute to workers' safety and health through safety climate of workplace. METHODS: Occupational accidents were analyzed at the manufacturing work site unit. A two step clustering process for the past patterns regarding the ROII from 2001 to 2009 was investigated. The ROII patterns were categorized based on regression analysis and the patterns were further divided according to the subtle changes with Mahalanobis distance and Ward's linkage. RESULTS: The first clustering of ROII through regression analysis showed 5 different functions; 29 work sites of the linear function, 50 sites of the quadratic function, 95 sites of the logarithm function, 62 sites of the exponential function, and 54 sites of the sine function. Fourteen clusters were created in the second clustering. There were 3 clusters in each function categorized in the first clustering except for sine function. Each cluster consisted of the work sites with similar ROII patterns, which had unique characteristics. CONCLUSION: The five different patterns of ROII suggest that tailored management activities should be applied to every work site. Based on these differences, the authors selected exemplary work sites and built a network to help the work sites to share information on safety climate and accident prevention measures. The causes of different patterns of ROII, building network and evaluation of this management model should be evaluated as future researches.

Typology of ROII Patterns on Cluster Analysis in Korean Enterprises

OBJECTIVES: Authors investigated the pattern of the rate of occupational injuries and illnesses (ROII) at the level of enterprises in order to build a network for exchange of experience and knowledge, which would contribute to workers' safety and health through safety climate of workplace. METHODS: Occupational accidents were analyzed at the manufacturing work site unit. A two step clustering process for the past patterns regarding the ROII from 2001 to 2009 was investigated. The ROII patterns were categorized based on regression analysis and the patterns were further divided according to the subtle changes with Mahalanobis distance and Ward's linkage. RESULTS: The first clustering of ROII through regression analysis showed 5 different functions; 29 work sites of the linear function, 50 sites of the quadratic function, 95 sites of the logarithm function, 62 sites of the exponential function, and 54 sites of the sine function. Fourteen clusters were created in the second clustering. There were 3 clusters in each function categorized in the first clustering except for sine function. Each cluster consisted of the work sites with similar ROII patterns, which had unique characteristics. CONCLUSION: The five different patterns of ROII suggest that tailored management activities should be applied to every work site. Based on these differences, the authors selected exemplary work sites and built a network to help the work sites to share information on safety climate and accident prevention measures. The causes of different patterns of ROII, building network and evaluation of this management model should be evaluated as future researches.

Risk Factors for Absenteeism due to Work related Musculo-skeletal Disorders among Korean Employees / 대한산업의학회지

OBJECTIVES: Absenteeism due to musculo-skeletal disorders (MSDs) of workers is an important index of occupational health. Since research on its causes is rare in Korea, the risk factors for absenteeism due to MSDs should be studied. METHODS: Using the 2nd Korean working condition survey data, we investigated the prevalence of absenteeism due to MSDs. We also analyzed the risk factors for absenteeism by multiple logistic regression analysis in Korean employees. RESULTS: Prevalence of absenteeism due to MSDs was 0.7% in all employees, 0.5% in men, and 0.9% in women. In logistic regression analysis, gender, age, presence of a representative worker organization, working on tight deadlines, and pace of work dependent on automated equipment/machine were risk factors of absenteeism due to MSDs for both sexes. For males, working time, working at a very high speed were additional risk factors. For females, pace of work dependent on numerical production, performance, and targets were additional risk factors. Although not included in the multiple logistic regression analysis, handling heavy loads in both sexes and average monthly income for women were risk factors in the univariate analysis. CONCLUSIONS: For absenteeism due to MSDs, the presence of a representative worker organization, along with work pace and its determinants were important risk factors.

Prevalence and Risk Factors of Hearing Loss Using the Korean Working Conditions Survey

BACKGROUND AND OBJECTIVES: The hearing loss of workers can occur when they are affected by age, otologic disease, and work-related risks such as noise and chemicals. Based on the Korean Working Conditions Survey (KWCS) in 2010, this research aimed to estimate the prevalence rate of hearing loss and to identify the risk factors affecting its occurrence. SUBJECTS AND METHODS: The subjects were 10019 employees who completed an interview conducted as part of KWCS in 2010. The prevalence rate of hearing loss according to sex, age, education, income, smoking, drinking, hypertension, industrial type, occupations, employment status, working period, and hazards at the workplace were assessed. The factors that could affect the occurrence of hearing loss were investigated based on a logistic regression analysis. RESULTS: The prevalence rate of hearing loss was 2.7%. In a logistic multivariate analysis, sex, age, occupations, working period, noise, and exposure to chemicals showed statistically significant correlations to the occurrence of hearing loss. The adjusted odd ratios were as follows: 1.74 [95% confidence interval (CI), 1.03-2.96] for males, 2.11 (95% CI, 1.14-3.89) for those in their 40s, 2.24 (95% CI, 1.19-4.20) for those in their 50s, 2.21 (95% CI, 1.18-4.15) for manage/professional works, 2.73 (95% CI, 1.69-4.41) for manufacturing, 2.07 (95% CI, 1.36-3.15) for those who have worked for more than 20 years, 1.72 (95% CI, 1.14-2.58) for noise exposure, 1.53 (95% CI, 1.02-2.30) for vibration exposure and 1.58 (95% CI, 1.11-2.24) for chemical exposure. CONCLUSIONS: The overall occupational and non-occupational risk factors related to employees' hearing loss were reviewed. In addition to the exposure to noise, occupational risks of hearing loss, such as isolated exposure to vibration and chemicals, and combined exposure to noise and these hazards, were identified. Multiple exposure to hazards, along with prolonged noise exposure increased the risk of hearing loss.

The Risk Rating System for Noise-induced Hearing Loss in Korean Manufacturing Sites Based on the 2009 Survey on Work Environments

OBJECTIVES: In Korea, an average of 258 workers claim compensation for their noise-induced hearing loss (NIHL) on an annual basis. Indeed, hearing disorder ranks first in the number of diagnoses made by occupational medical check-ups. Against this backdrop, this study analyzed the impact of 19 types of noise-generating machines and equipment on the sound pressure levels in workplaces and NIHL occurrence based on a 2009 national survey on work environments. METHODS: Through this analysis, a series of statistical models were built to determine posterior probabilities for each worksite with an aim to present risk ratings for noise levels at work. RESULTS: It was found that air compressors and grinding machines came in first and second, respectively in the number of installed noise-generating machines and equipment. However, there was no direct relationship between workplace noise and NIHL among workers since noise-control equipment and protective gear had been in place. By building a logistic regression model and neural network, statistical models were set to identify the influence of the noise-generating machines and equipment on workplace noise levels and NIHL occurrence. CONCLUSION: This study offered NIHL prevention measures which are fit for the worksites in each risk grade.

Occupational Injury Statistics in Korea

OBJECTIVES: The occupational accident rate was officially reported to be 0.77 per 100 workers in 2001 and 0.70 in 2009. The stagnant decrease in accident rate raises a question about the effectiveness of prevention activity because there have been active prevention efforts in the past 10 years. It is also necessary to know the exact status of occupational injuries to direct a prevention strategy. METHODS: The author re-analyzed occupational injury statistics to find the reason for stagnant decreases in occupational injuries. Compensated occupational injuries cases were used to calculate fatal and non-fatal injury rates. Injuries from commuting accidents and sports activities were excluded as well as occupational diseases. The number of workers was adjusted to that of full time equivalent employees. RESULTS: The fatal injury rate excluding injuries associated with commuting accidents, sports activities, and occupational diseases decreased from 12.59 in 2001 to 8.20 in 2009. In 2007, 67.5% of accidents that involved being caught in objects, which are mostly caused by machines and equipment, occurred in the manufacturing industry; this type of incident has decreased since 2001. The fatal and non-fatal injury rates in the manufacturing industry have continuously decreased while the rates in the service industry have not changed from 2001 to 2009. Non-fatal injuries might not be reported in many cases. The number of insured workers was underestimated as long working hours were not adjusted for in the reporting system. CONCLUSION: The occupational fatal injury rate has decreased and the non-fatal injury rate might have decreased during the last 10 years, although the statistics show stagnancy. The decrease of the injury rate was countervailed by various factors. Hence, the current accident rate does not reflect the actual situation of accidents in Korea. Korea needs to develop an improved system to more accurately calculate occupational fatal and non-fatal injury rates.

The Prevalence of Work Related Sickness Absences According to the Second Korean Working Condition Survey / 대한산업의학회지

OBJECTIVES: Worker's health is an important index used to evaluate working conditions and to prioritize prevention policies. However, this index has never before been calculated in Korea. The purpose of this study was to calculate the prevalence of health problems caused by work related sickness absences using the second Korean Working Condition Survey (KWCS) conducted in 2010. METHODS: The second KWCS was conducted from June to October 2010 as a household survey for employed workers. The work related sickness absence rate was estimated using gender, age, business size, occupational status, level of education, and level of income. A logistic regression was performed in order to evaluate the relationship of the work related sickness absence with general characteristics and work-related conditions. RESULTS: The rate of work related sickness absence was 1.8(+/-0.2)% for all workers, with 6.0(+/-0.3)% of it being in agriculture, forestry, and fishing, and 2.2(+/-0.5)% in manufacturing. Musculoskeletal disorders (MSD) were the most common work related disorder [1.01(+/-0.12)%], followed by psychiatric disorders [0.18(+/-0.05)%], and respiratory disorders [0.14(+/-0.04)%]. The highest odds ratio (OR) for the work related sickness absence rate was in self-employed workers with employees (OR=2.23, 95%CI=1.05~4.74). CONCLUSIONS: The work related sickness absence rate for all workers, both self-employed and employed, including agriculture, forestry and fishing workers, and wholesale and retail trade workers was 1.8(+/-0.2)%. Because the KWCS was based on a self-reported questionnaire survey, this figure might be overestimated. In addition, it might omit chronic occupational disease and death cases.

Polypoid Cystitis Mimicking Bladder Tumor: A Case Report

Polypoid cystitis without a history of catheterization is rare. We report a case in which the condition occurred in a 16-year-old girl complaining of dysuria, urgency, frequency, and a residual urine sensation. Cystography revealed a large intravesical filling defect with bladder distension, while sonography and CT demonstrated a large, inhomogeneously enhancing solid mass in the urinary bladder.