Inchul Jeong

Working Hours and Cardiovascular Disease in Korean Workers: A Case-control Study

Working Hours and Cardiovascular Disease in Korean Workers: A Case‐control Study: Inchul JEONG, et al. Graduate School of Public Health, Yonsei University, Republic of Korea—

Allergic Diseases and Multiple Chemical Sensitivity in Korean Adults

Purpose Multiple chemical sensitivity (MCS) is a clinical syndrome representing multi-organ and psychological symptoms caused by chronic exposure to various chemicals in low concentrations. We evaluated the prevalence and related factors of MCS targeting Korean adults using the Quick Environmental Exposure and Sensitivity Inventory (QEESI©). Methods A total of 446 participants were recruited from Severance Hospital. Participants underwent a questionnaire interview including questions on sociodemographic factors, occupational and environmental factors, allergic diseases, and the QEESI©. Among them, 379 participants completed the questionnaire and the QEESI©. According to the QEESI© interpretation results, participants were divided into very suggestive (VS) group and less suggestive (LS) group. Results The estimated prevalence of MCS was higher in allergic patients than non-allergic participants (19.7% and 11.3%, respectively, P=0.04). In the multivariate logistic regression analysis, ages of 30-39 (OR, 2.94; 95% CI, 1.25-6.95) and those of 40-49 (OR, 2.51; 95% CI, 1.02-6.21) were significantly related to MCS compared to those aged less than 30 years. Female sex (OR, 2.16; 95% CI, 1.11-4.18), experience of dwelling in a new house (OR, 2.05; 95% CI, 1.04-4.03), and atopic dermatitis (OR, 1.95; 95% CI, 1.04-3.69) were also significantly related to MCS. However, only age of 30-39 in the allergic group was significant in the stratified analysis. Conclusions The estimated prevalence of MCS was higher among allergic patients than non-allergic participants. People with experience of dwelling in a new house and atopic dermatitis were more at risk of being intolerant to chemicals. Further studies to provide the nationally representative prevalence data and clarify risk factors and mechanisms of MCS are required.

A New Disability Rating Method according to the Job Using the Korean Academy of Medical Science Disability Guideline

The purpose of this study was to develop a disability rating scale according to job classification using the Korean Academy of Medical Society (KAMS) guidelines. All jobs were categorized based on their level of physical activity and professional skills. The KAMS guidelines were used for the impairment rating. We modified the California Schedule for rating permanent disabilities. The differences were plotted to compare between the impairment rate and the job-adjusted disability rate. The KAMS job-adjusted disability rates were then compared to the McBride and workers compensation rates. A total of 1,206 occupations were classified into 44 groups. The occupational disability indexes were rated on a scale of 1 to 7. The differences in the McBride disability rates varied inconsistently from 0% to 35%, while the differences in the KAMS disability rates were between 0% and 18%. The KAMS disability rates were slightly higher than the McBride disability rates for the upper extremities, but were lower for the lower extremities and internal organs. This is the first Korean job-adjusted disability rating method. There are several limitations, but its impairment rating is more scientific and reflects the current Korean occupational environment.

Return-to-Work According to Impairment Type Among Occupationally Injured Workers in Korea

This study examined the association between return-to-work and impairment type. Database of the Korea Workers Compensation and Welfare Service was used to identify disabled persons; and return-to-work information was obtained from the Korea Employment Information Services database. The study participants were 79,328 persons who received Workers compensation and who were confirmed as disabled during 2009-2011. Logistic regression was used to analyze the association between return-to-work and impairment type, adjusted by age, sex, impairment severity, pre-injury businesses size, and pre-injury occupational category. Compared to injuries of the upper limbs, the odds ratio of return-to-work was 0.63 (95% CI, 0.60-0.65) for injuries involving the lower limbs, 0.62 (95% CI, 0.59-0.66) for the spine, 0.75 (95% CI, 0.66-0.86) for the eyes, 0.98 (95% CI, 0.77-1.25) for the oral cavity, 0.44 (95% CI, 0.37-0.53) for the ears, 1.02 (95% CI, 0.83-1.25) for the figure, 0.75 (95% CI, 0.72-0.79) for pain, and 0.36 (95% CI, 0.32-0.41) for neuropsychiatric impairment. These findings indicate that impairment type influences return-to-work rates.

Impact of near work on perceived stress according to working hours: The Korea National Health and Nutrition Examination Survey VI (2013–2015)

The purpose of this study was to investigate the relationships among working hours, near work time, and perceived stress. In total, data of 3,776 workers from the Korea National Health and Nutrition Examination Survey VI were examined. The workers’ working hours per week, daily near work time, and complaints of perceived stress were analyzed in conjunction with other sociodemographic and occupation-related variables. Multivariate logistic analysis found that workers with 3 and ≥4 hours of near work were more likely to report high perceived stress than were the reference group who had <1 hour per day of near work, with odds ratios (ORs) (95% confidence intervals [CIs]) of 1.34 (1.01–1.78) and 1.94 (1.53–2.46), respectively. Additionally, those working 50 and more hours a week were more likely to report high perceived stress with ORs of 1.51 (1.19–1.90) and 1.88 (1.42–2.48), respectively. When stratified by working hours, workers with daily near work time of ≥4 hours were more likely to report high perceived stress with ORs of 2.21 (1.45–3.37), 2.27 (1.30–3.97), and 3.47 (1.80–6.69), among the workers with 40–49, 50–59, and ≥60 weekly working hours, respectively. Workers with greater near work time are at risk for high perceived stress. Moreover, this risk was found to be higher among workers with longer working hours. Therefore, work cycle modification and reductions in near work time are necessary to prevent stress-related health outcomes.

Impacts of Return-to-Work Type and Period on Job Retention in Workers with Occupational Injuries and Diseases

Background Despite the necessity of job retention in achieving return-to-work (RTW) goals, many workers leave their jobs after returning to work. The objective of this study was to examine the impacts of RTW type and period on job retention in Korean workers with occupational injuries and diseases. Methods Data were derived from the Panel Study of Workers Compensation Insurance, including data from 2,000 systemically sampled workers who had finished recuperation in 2012; three waves of survey data were included in the analyses. Workers who returned to work (n = 1,610) were included in the analysis of the relationship between RTW type and job retention, and 664 workers who returned to their original workplaces were included in the analysis of the relationship between RTW period and job retention. The participants completed a questionnaire, and administrative data were provided by workers compensation insurance. Results A Cox proportional-hazards regression analysis showed an increased hazard ratio (HR) for non-retention of 2.66 (95% confidence interval, 2.11–3.35) in reemployed workers compared to that in workers returning to their original workplaces. Among workers returning to their original workplaces, HRs for non-retention were increased in workers with a RTW period of 13–24 months (3.03 [1.52–6.04]) and > 24 months (5.33 [2.14–13.25]) compared to workers with a RTW period of ≤ 3 months. Conclusion RTW type and period were significantly related to job retention, suggesting that policies for promoting job retention rate should be implemented.

Effects of changes in occupational stress on the depressive symptoms of Korean workers in a large company: a longitudinal survey

BackgroundProspective studies on occupational stress and depression among Korean workers are scarce. This study aimed to investigate the causal relationship between changes in occupational stress and the presence of depression.MethodsThis study analyzed data from a survey conducted with workers in a large Korean company (2015–2016). Occupational stress was measured using the Korean Occupational Stress Scale, and depression was screened using the WHO-5 Well-being Index. The levels of occupational stress were grouped in quartiles based on subjects’ occupational stress scores in 2015, and changes in occupational stress were measured using the score changes between the 2015 and 2016 surveys. Subjects were divided into four groups according to the presence or absence of depression in 2015 and 2016: a non-depressed group whose mental health did not change, a non-depressed group whose mental health deteriorated, a depressed group that continued to be depressed, and a depressed group whose symptoms of depression were alleviated. Logistic regression analysis was used to calculate the odds ratios (ORs) and confidence intervals (CIs) of the subjects’ deterioration in mood or alleviation of depression by occupational stress levels and changes.ResultsThe OR for developing depressive symptoms was 2.51 (95% CI 1.46–4.33) and 2.73 (95% CI 1.39–5.36) in the third and the fourth quartiles of occupational stress, respectively, compared to the first quartile. When the occupational stress score increased by 1 point, the OR for increasing depressive symptoms was 1.07 (95% CI 1.04–1.10). There was no significant difference in the alleviation of depressive symptoms between the groups by level of occupational stress. However, when the occupational stress score decreased by 1 point, the OR for alleviating depressive symptoms was 1.08 (95% CI 1.05–1.11).ConclusionThe results showed that increased occupational stress increased the presence of depressive symptoms, and that reduced occupational stress suppressed the development of depressive symptoms. More attention should be paid to stress management among workers.

Two Cases of Lung Cancer in Foundry Workers

BackgroundIron and steel foundry workers are exposed to various toxic and carcinogenic substances including crystalline silica, polycyclic aromatic hydrocarbons, and arsenic. Studies have been conducted on lung cancer in iron and steel founding workers and the concentration of crystalline silica in foundries; however, the concentration of crystalline silica and cases of lung cancer in a single foundry has never been reported in Korea. Therefore, the authors report two cases of lung cancer and concentration of crystalline silica by the X-ray diffraction method.Case presentationA 55-year-old blasting and grinding worker who worked in a foundry for 33xa0years was diagnosed with lung cancer. Another 64-year-old forklift driver who worked in foundries for 39xa0years was also diagnosed with lung cancer. Shot blast operatives were exposed to the highest level of respirable quartz (0.412xa0mg/m3), and a forklift driver was exposed to 0.223xa0mg/m3.ConclusionsThe lung cancer of the two workers is very likely due to occupationally related exposure given their occupational history, the level of exposure to crystalline silica, and epidemiologic evidence. Further studies on the concentration of crystalline silica in foundries and techniques to reduce the crystalline silica concentration are required.