Health Effects Associated With Humidifier Disinfectant Use: A Systematic Review for Exploration

Background@#It has been 10 years since the outbreak of lung disease caused by humidifier disinfectants in Korea, but the health effects have not yet been summarized. Therefore, this study aims to systematically examine the health effects of humidifier disinfectants that have been discovered so far. @*Methods@#All literature with humidifier disinfectants and their representative components as the main words were collected based on the web, including PubMed, Research Information Sharing Service, and government publication reports. A total of 902 studies were searched, of which 196 were selected. They were divided into four groups: published human studies (group 1), published animal and cytotoxicology studies (group 2), technical reports (group 3), and gray literature (group 4). @*Results@#Out of the 196 studies, 97 (49.5%) were published in peer-reviewed journals as original research. Group 1 consisted of 49 articles (50.5%), while group 2 consisted of 48 articles (49.5%). Overall, respiratory diseases such as humidifier disinfectant associated lung injury, interstitial lung disease, and asthma have a clear correlation, but other effects such as liver, heart, thymus, thyroid, fetal growth, metabolic abnormalities, and eyes are observed in toxicological experimental studies, but have not yet been identified in epidemiologic studies. @*Conclusion@#The current level of evidence does not completely rule out the effects of humidifier disinfectants on extrapulmonary disease. Based on the toxicological evidence so far, it is required to monitor the population of humidifier disinfectant exposure continuously to see if similar damage occurs.

Risk of Cerebro-Cardiovascular Diseases among Police Officers and Firefighters:A Nationwide Retrospective Cohort Study

Purpose@#Police officers and firefighters are exposed to risk factors for cerebro-cardiovascular diseases, and the actual risk is expected to increase compared with other occupational groups. The present study aimed to estimate the risks of cerebro-cardiovascular diseases in police officers and firefighters compared to other occupational groups. @*Materials and Methods@#Using the National Health Insurance Service data, we constructed a retrospective cohort of public officers. Three-year consecutive health insurance registration data were used to identify police officers and firefighters. Cerebro-cardiovascular diseases consisted of acute myocardial infarction, other ischemic heart disease, cardiac arrhythmia, and stroke. We compared the incidences of cerebro-cardiovascular diseases between each of the two occupational groups (police officers and firefighters) and other public officers by calculating standardized incidence ratios (SIRs). @*Results@#SIRs and 95% confidence intervals of all cerebro-cardiovascular diseases for police officers and firefighters were 1.71 (1.66–1.76) and 1.22 (1.12–1.31), respectively, as compared with all public officers. The incidence ratios remained significantly higher compared to general and education officers. Subgroup analyses for myocardial infarction, stroke, and cardiac arrhythmia exhibited significant increases in incidence ratios among police officers and firefighters. @*Conclusion@#This study suggests that both police officers and firefighters are at high risk of cerebro-cardiovascular diseases.Therefore, medical protection measures for these occupational groups should be improved.

Insufficient Rest Breaks at Workplace and Musculoskeletal Disorders Among Korean Kitchen Workers

Background@#The socioeconomic burden of musculoskeletal disorders (MSDs) is significant, and kitchen work is a high-risk occupation for MSDs due to the intensive manual workload and repetitive movements that are involved. However, there are very few studies on MSDs and rest breaks as a workplace intervention among kitchen workers. This study examined the relationship between insufficient rest breaks and increased MSD risk among Korean kitchen workers. @*Methods@#Sociodemographic and occupational factors of 1,909 kitchen workers were collected from the 3rd–4th Korean Working Conditions Survey data. Five items on rest breaks at work were categorized into two groups, “sufficient” and “insufficient.” The number of MSDs and work-related MSDs (WMSDs), an outcome variable, was obtained from the sum of MSDs/WMSDs in three anatomical sites (back, neck, and upper limb, lower limb). The association between rest breaks and MSDs was estimated using zero-inflated negative binomial analyses, with adjustments for age, education level, and weekly working hours, and the analyses were stratified by sex. @*Results@#After adjustment, significant associations were found between insufficient rest breaks and an increased risk of MSDs (odds ratio [OR] 1.68 95% confidence interval [CI] 1.11–2.54) and WMSDs (OR 1.40 95% CI 1.01–1.96) among female kitchen workers. Insufficient rest breaks were significantly associated with MSDs in female kitchen workers in all three anatomical sites. @*Conclusion@#This study emphasizes the need for rest breaks as a workplace intervention for preventing MSDs in kitchen workers. Further studies to reveal the causality of this relationship are required.

The Occupational Characteristics and Health Status of Workers in Geographically Isolated and Confined Areas in the Republic of Korea

Background@#This study investigates the safety and health status of geographically isolated and confined workers. @*Methods@#This study was conducted in Baekryeong Island in Korea in 2020. The agestandardized prevalence ratios (aSPR) for occupational injury, unmet medical needs, psychological status, and lifestyle were estimated from the available data. Also, we compared the aSPRs of workers in Baekryeong Island with a reference study population who participated in a nationally representative survey in Korea. @*Results@#The study revealed that Baekryeong Island workers had an increased risk of acquiring health and safety problems compared to the general worker population. The island workers showed a significant increase in unmet medical care (aSPR, 5.319; 95% confidence interval [CI], 3.984–6.958) and occupational injury (aSPR, 8.371; 95% CI, 3.820–15.892). @*Conclusion@#This study identified the safety and health problems of geographically isolated workers in Baekryeong Island. The risk of occupational injury and unmet medical care are simultaneously highlighted in the region's population, thereby underscoring the importance of prevention.

The Occupational Characteristics and Health Status of Workers in Geographically Isolated and Confined Areas in the Republic of Korea

Background@#This study investigates the safety and health status of geographically isolated and confined workers. @*Methods@#This study was conducted in Baekryeong Island in Korea in 2020. The agestandardized prevalence ratios (aSPR) for occupational injury, unmet medical needs, psychological status, and lifestyle were estimated from the available data. Also, we compared the aSPRs of workers in Baekryeong Island with a reference study population who participated in a nationally representative survey in Korea. @*Results@#The study revealed that Baekryeong Island workers had an increased risk of acquiring health and safety problems compared to the general worker population. The island workers showed a significant increase in unmet medical care (aSPR, 5.319; 95% confidence interval [CI], 3.984–6.958) and occupational injury (aSPR, 8.371; 95% CI, 3.820–15.892). @*Conclusion@#This study identified the safety and health problems of geographically isolated workers in Baekryeong Island. The risk of occupational injury and unmet medical care are simultaneously highlighted in the region's population, thereby underscoring the importance of prevention.

Insufficient Rest Breaks at Workplace and Musculoskeletal Disorders Among Korean Kitchen Workers

Background@#The socioeconomic burden of musculoskeletal disorders (MSDs) is significant, and kitchen work is a high-risk occupation for MSDs due to the intensive manual workload and repetitive movements that are involved. However, there are very few studies on MSDs and rest breaks as a workplace intervention among kitchen workers. This study examined the relationship between insufficient rest breaks and increased MSD risk among Korean kitchen workers. @*Methods@#Sociodemographic and occupational factors of 1,909 kitchen workers were collected from the 3rd–4th Korean Working Conditions Survey data. Five items on rest breaks at work were categorized into two groups, “sufficient” and “insufficient.” The number of MSDs and work-related MSDs (WMSDs), an outcome variable, was obtained from the sum of MSDs/WMSDs in three anatomical sites (back, neck, and upper limb, lower limb). The association between rest breaks and MSDs was estimated using zero-inflated negative binomial analyses, with adjustments for age, education level, and weekly working hours, and the analyses were stratified by sex. @*Results@#After adjustment, significant associations were found between insufficient rest breaks and an increased risk of MSDs (odds ratio [OR] 1.68 95% confidence interval [CI] 1.11–2.54) and WMSDs (OR 1.40 95% CI 1.01–1.96) among female kitchen workers. Insufficient rest breaks were significantly associated with MSDs in female kitchen workers in all three anatomical sites. @*Conclusion@#This study emphasizes the need for rest breaks as a workplace intervention for preventing MSDs in kitchen workers. Further studies to reveal the causality of this relationship are required.

The relationship between night work and breast cancer

BACKGROUND: Since the International Agency for Research on Cancer classified shift work that involves circadian disruption as “probably carcinogenic to humans,” there has been growing concern on the relationship between night work and breast cancer. In Korea, about 10–15% of workers are engaged in night-shift work, and breast cancer is one of the most common cancers in women. The purpose of this study was to review epidemiologic evidence on the relationship between night work and breast cancer. METHODS: We reviewed 21 original articles and 5 meta analyses on relationship between nightwork and breast cancer, and investigated the compensation criteria of Denmark. RESULTS: The association between breast cancer and night work has been reported by numerous epidemiologic studies, including cohort studies, case-control studies, and meta-analysis. However, a dose-response relationship has not clearly emerged among workers exposed to less than 20 years of night work. CONCLUSION: Although there are some limitations to the epidemiological studies so far, further consideration of breast cancer cases in patients with high exposure to night work is needed to assess breast cancer as a work-related disease.

Prediction of Return-to-original-work after an Industrial Accident Using Machine Learning and Comparison of Techniques

BACKGROUND: Many studies have tried to develop predictors for return-to-work (RTW). However, since complex factors have been demonstrated to predict RTW, it is difficult to use them practically. This study investigated whether factors used in previous studies could predict whether an individual had returned to his/her original work by four years after termination of the worker's recovery period. METHODS: An initial logistic regression analysis of 1,567 participants of the fourth Panel Study of Worker's Compensation Insurance yielded odds ratios. The participants were divided into two subsets, a training dataset and a test dataset. Using the training dataset, logistic regression, decision tree, random forest, and support vector machine models were established, and important variables of each model were identified. The predictive abilities of the different models were compared. RESULTS: The analysis showed that only earned income and company-related factors significantly affected return-to-original-work (RTOW). The random forest model showed the best accuracy among the tested machine learning models; however, the difference was not prominent. CONCLUSION: It is possible to predict a worker's probability of RTOW using machine learning techniques with moderate accuracy.

Risk factors associated with mortality from pneumonia among patients with pneumoconiosis

BACKGROUND: The aim of this study was to evaluate factors associated with increased risk of mortality from pneumonia among patients with pneumoconiosis. METHODS: Medical records of 103 pneumoconiosis patients hospitalized for pneumonia were investigated. Seven patients who had lung cancer or other malignancy and 13 patients with insufficient medical record were excluded. Two female patients were excluded due to small number to analyze. The subjects were divided into two groups by clinical outcome of pneumonia, the deceased group and the survival group. The two groups were compared in terms of age, smoking history, episode of recent pneumonia, concomitancy of interstitial fibrosis or fungal ball infection, extent of small opacities, grade of large opacities and results of spirometry. Multiple logistic regression was applied to determine the association between these variables and mortality from pneumonia. RESULTS: The deceased group showed more frequent history of recent pneumonia (p = 0.006), higher prevalence of interstitial fibrosis (p = 0.007) and longer hospitalization period (p = 0.044). The proportion of subjects who had decreased FVC, less than 70 % of predicted value, was higher in the deceased group (p < 0.001). In multiple logistic regression, after adjusting age, smoking history, recent pneumonia, fungal ball, large opacity, profusion and FVC (or FEV1) less than 70 % of predicted value, history of recent pneumonia, concomitancy of interstitial fibrosis, type of pneumoconiosis and fungal ball presented statistically significant association with mortality from pneumonia. CONCLUSIONS: The concomitancy of fungal ball or interstitial fibrosis, history of recent pneumonia within last 90 days, type of pneumoconiosis, FVC less than 70 % of predicted value, FEV1 less than 70 % of predicted value presented statistically significant association with mortality from pneumonia. More attention should be given to patients who have such factors when treating pneumonia with pneumoconiosis.

Factors associated with suicide ideation among subway drivers in Korea

BACKGROUND: There were several suicide events of subway drivers in Korea. The aim of this study is to explore work-related factors associated with suicide ideation among subway drivers. METHODS: We analyzed data from 980 male subway drivers. A section of the Korean version of the Composite International Diagnostic Interview (K-CIDI 2.1) was administered by trained interviewers to judge whether a driver has suicide ideation and to diagnose psychiatric disorders. A questionnaire was also administered to collect data on sociodemographic characteristics, work environments, occupational stress, person under train (PUT) experience, and work-related problems. Occupational stress was examined by using the Korean Occupational Stress Scale (KOSS). Logistic regression was applied to evaluate the association between work-related factors and suicide ideation among subway drivers. RESULTS: Regarding work-related problems, conflict with passengers and sudden stops due to the emergency bell were significantly associated with suicide ideation. MDD, PTSD, and panic disorder were strongly associated with suicide ideation. In the analysis of occupational stress, insufficient job control (OR 2.34) and lack of reward (OR 2.52) were associated with suicide ideation even after being adjusted for psychiatric disorders and other work-related factors. CONCLUSIONS: Insufficient job control and lack of reward were associated with suicide ideation among subway drivers. Strategies for drivers to have autonomy while working and to achieve effort-reward balance should be implemented. Furthermore, drivers who have experienced negative work-related problems should be managed appropriately.

Work-related COPD after years of occupational exposure

BACKGROUND: Cigarette smoking is known as the most important risk factor of chronic obstructive pulmonary disease (COPD). However, occupational exposure to other substances can result in COPD. CASE REPORT: A 76-year-old man with occupational exposures to mixtures of silica dust, gas, and fumes for 10 years and with a 25 pack-year smoking history was diagnosed with COPD. His computed tomogram scan revealed some hyperinflation with emphysematous change in both upper lobes. In the pulmonary function tests, his post-bronchodilator forced vital capacity (FVC), forced expiratory volume in one second (FEV1), and FEV1/FVC% were 2.20 L (67% of the predicted value), 1.12 L (52% of the predicted value), and 51%, respectively, indicating moderate COPD. This case of COPD was confirmed as a work-related disease by the Occupational Lung Disease Research Institute in Korea Workers' Compensation & Welfare Service. CONCLUSION: Exposure to various substances such as silica dust, gas, and fumes from furnace and boiler installation was likely the cause of COPD in this patient. Thus, occupational exposure should be considered an important risk factor of COPD.

The effects of individual, occupational, and supportive factors on successful return to work using a structural equation model

OBJECTIVES: We aimed to ascertain the relationship between several factors and successful return to work using a structural equation model. METHODS: We used original data from the Panel Study of Worker's Compensation Insurance, and defined four latent variables as occupational, individual, supportive, and successful return to work. Each latent variable was defined by its observed variables, including age, workplace size, and quality of the medical services. A theoretical model in which all latent variables had a relationship was suggested. After examining the model, we modified some pathways that were not significant or did not fit, and selected a final structural equation model that had the highest goodness of fit. RESULTS: All three latent variables (occupational, individual, and supportive) showed statistically significant relationships with successful return to work. The occupational and supportive factors had relationships with each other, but there was no relationship between individual and the other factors. Nearly all observed variables had significance with their latent variables. The correlation coefficients from the latent variables to successful return to work were statistically significant and the indices for goodness of fit were satisfactory. In particular, four observed variables-handicap level, duration of convalescence, working duration, and support from the company-showed construct validities with high correlation coefficients. CONCLUSIONS: All factors that we examined are related to successful return to work. We should focus on the supportive factor the most because its variables are modifiable to promote a return to work by those injured in their workplace.

The association between psychiatric disorders and work-related problems among subway drivers in Korea

OBJECTIVES: This study aimed to find the prevalence and occupational risk factors for major psychiatric disorders among subway drivers in South Korea. METHODS: Of all 998 current subway drivers, 995 participated in this study. The Korean version of the Composite International Diagnostic Interview (K-CIDI 2.1) was administered by trained interviewers to diagnose psychiatric disorders in all participants. The questions on socio-demographic characteristics and working conditions included some questions related to a person under train (PUT) experience and work-related problems. One-year prevalence and lifetime prevalence of major depressive disorder (MDD), post-traumatic stress disorder (PTSD), and panic disorder were diagnosed through the interview. The standardized prevalence ratios (SPRs) of these three disorders were calculated in the sample of subway drivers using the 2011 Korean National Epidemiologic Survey data as a basis. Multiple logistic regressions were performed to determine the association between work-related factors and the prevalence of the psychiatric disorders. RESULTS: The standardized prevalence ratios (SPRs) for a 1-year prevalence of MDD and PTSD among subway drivers were 1.1 (95% CI 0.7-1.7) and 5.6 (95% CI 3.1-8.8), respectively. Conflict with passengers was significantly associated with an increased risk for both MDD and PTSD in 1-year and in lifetime prevalence. Experiencing a sudden stop due to an emergency bell increased the risk of the lifetime prevalence of MDD (OR 2.61, 95% CI 1.14-6.97) and PTSD (OR 7.53, 95% CI 1.77-32.02). The risk of PTSD significantly increased among drivers who once experienced a near accident in terms of both the 1-year prevalence (OR 8.81, 95% CI 1.96-39.3) and the lifetime prevalence (OR 6.36, 95% CI 2.40-16.90). CONCLUSIONS: PTSD and panic disorder were more prevalent among subway drivers than in the general population. We found that having a conflict with passengers, a near accident, and a breakdown while driving can be risk factors for psychiatric disorders among subway drivers. Therefore, a prompt and sensitive approach should be introduced for these high risk groups within the subway company.