Epidemiology of Urolithiasis with Sex and Working Status Stratification Based on the National Representative Cohort in Republic of Korea

Background@#This study aimed to estimate the annual prevalence and incidence of urolithiasis stratified by work status based on a large nationwide sample. @*Methods@#This study used data from the National Health Insurance Service-National Sample Cohort from 2002 to 2015. The prevalence and incidence of urolithiasis were estimated based on work status and gender stratification. The risk of urolithiasis among workers was calculated using age-standardized incidence ratio with stratification of work type. @*Results@#The prevalence of urolithiasis was significantly higher in workers than in non-workers, especially men, during the follow-up period. The total estimated number of urolithiasis cases was 41,086 and the overall incidence of urolithiasis was 0.3%. The age-standardized incidence ratio of urolithiasis was significantly higher among the total workers (1.14; 95% confidence interval, 1.13–1.16), self-employed workers (1.08; 95% confidence interval, 1.06–1.11), and paid workers (1.19; 95% confidence interval, 1.17–1.21) than among the non-working population. @*Conclusions@#Workers, especially paid workers and men, were vulnerable to urolithiasis. Further studies are required to investigate the effects of working conditions on urolithiasis.

The Association Between Long Working Hours and Infertility

Background@#This study aimed to investigate whether working long hours was related to infertility among female Korean workers, while taking age into consideration. @*Methods@#We used data from the 2018 National Survey on Fertility and Family Health and Welfare in Korea that is a cross-sectional, nationally representative, and population-based survey. Infertility was defined as women who were not pregnant after regular unprotected intercourse for a year. Working long hours was classified as ≥52 hours, and subgroups as per age were classified on the basis of being younger or older than 40 years of age. Differences in infertility risk between the long working hour group and none were estimated in crude and fully adjusted logistic regression models with age-group stratification. @*Results@#Of 5,909 Korean female workers, the crude and adjusted odds ratios (95% confidence intervals) of infertility for working long hours were 1.295 (0.948–1.737) and 1.303 (0.921–1.809), respectively. In the subgroup of patients below 40 years of age, the crude and adjusted odds ratios (95% confidence interval) were 1.957 (1.216–3.039) and 1.921 (1.144–3.120), whereas those aged 40 years or older had 0.994 (0.647–1.471) and 0.939 (0.560–1.501), respectively. The weighted prevalence of infertility increased as weekly working hours increased only for the younger than 40-year subgroup. @*Conclusions@#Infertility is associated with working long hours, especially in young-aged workers. Thus, the working schedule must be structured to better suit young female workers.

Associations of Abnormal Sleep Duration with Occupational and Leisure-time Physical Activity in the Working Population: A Nation-wide Population-based Study

Background@#The present study investigated the association between two domains of physical activity (occupational physical activity [OPA] and leisure-time physical activity [LTPA]) and sleep duration. @*Methods@#We investigated 3,421 paid workers from the Korea National Health and Nutrition Examination Survey, 2014–2015. Sleep duration was categorized into three categories (short for less than 5 h, optimal for 5–9 h, and long for more than 9 h). OPA and LTPA were defined in terms of answers to relevant questions. Odds ratios were calculated for sleep duration according to each physical activity domain using multinomial logistic regression models. @*Results@#There were 464 subjects (13.6%) who showed short sleep duration, and 169 subjects (4.9%) who showed long sleep duration. Prevalence of OPA and LTPA was higher in male workers than in female workers (for OPA: 3.67% and 1.76%, respectively, p = 0.0108; for LTPA: 16.14% and 6.07%, respectively, p < 0.0001). The odds ratio of OPA for long sleep duration in female workers was 3.35 (95% confidence interval, 1.37–8.21). Otherwise, LTPA was not associated with sleep duration in female paid workers, nor both physical activity domains in male paid workers. @*Conclusion@#Female paid workers with work-related physical activity were at risk of oversleeping. These findings also suggested that physical activity has distinct associations with sleep duration according to the physical activity domains and sex.

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.

Associations of Abnormal Sleep Duration with Occupational and Leisure-time Physical Activity in the Working Population: A Nation-wide Population-based Study

Background@#The present study investigated the association between two domains of physical activity (occupational physical activity [OPA] and leisure-time physical activity [LTPA]) and sleep duration. @*Methods@#We investigated 3,421 paid workers from the Korea National Health and Nutrition Examination Survey, 2014–2015. Sleep duration was categorized into three categories (short for less than 5 h, optimal for 5–9 h, and long for more than 9 h). OPA and LTPA were defined in terms of answers to relevant questions. Odds ratios were calculated for sleep duration according to each physical activity domain using multinomial logistic regression models. @*Results@#There were 464 subjects (13.6%) who showed short sleep duration, and 169 subjects (4.9%) who showed long sleep duration. Prevalence of OPA and LTPA was higher in male workers than in female workers (for OPA: 3.67% and 1.76%, respectively, p = 0.0108; for LTPA: 16.14% and 6.07%, respectively, p < 0.0001). The odds ratio of OPA for long sleep duration in female workers was 3.35 (95% confidence interval, 1.37–8.21). Otherwise, LTPA was not associated with sleep duration in female paid workers, nor both physical activity domains in male paid workers. @*Conclusion@#Female paid workers with work-related physical activity were at risk of oversleeping. These findings also suggested that physical activity has distinct associations with sleep duration according to the physical activity domains and sex.

Multidimensional sleep quality of dependent self-employment workers

Anxiety, Depression and Sleep Disturbance among Customer-Facing Workers

The Effects of Workplace Rest Breaks on Health Problems Related to Long Working Hours and Shift Work among Male Apartment Janitors in Korea

BACKGROUND: Rest breaks at work are reported to reduce fatigue and job stress. Apartment janitors in Korea who perform night shift work and work long hours can be exposed to various health problems (HPs). However, few studies have evaluated relationships between their rest breaks and HPs. This study was conducted to examine the relationships between long working hours, shift work, and insufficient rest breaks and HPs among Korean apartment janitors.METHODS: Data on 1,212 selected male apartment janitors were obtained from the 3rd and 4th Korean Working Conditions Surveys. Demographic and occupational characteristics were collected using self-reported questionnaires. Rest breaks at work were classified as “sufficient” or “insufficient.” Long working hours were considered as working more than 60 hours per week. Zero-inflated negative binomial (ZINB) regression was performed to investigate the effects of shift work and long working hours on HPs and the effects of rest breaks on relationships between HPs and long working hours and shift work.RESULTS: Among those with insufficient rest breaks at work, significant associations were found between long working hours and the risk of HPs [odds ratio (OR) = 1.489; 95% confidence interval (CI) = 1.038–2.136] and work-related HPs (WRHPs) [OR 1.621; 95% CI = 1.156–2.272], and between shift work and HPs [OR = 1.603; 95% CI = 1.084–2.372]. These relationships became nonsignificant when sufficient rest breaks were provided.CONCLUSION: It is important to provide breaks at work to reduce HPs because of long working hours and shift work among aged workers such as apartment janitors.

Multidimensional sleep quality of dependent self-employment workers

BACKGROUND@#The number of workers in non-standard employment (NSE) is increasing due to industrial change and technological development. Dependent self-employment (DSE), a type of NSE, was created decades ago. Despite the problems associated with this new type of employment, few studies have been conducted on the effects by DSE on health, especially sleep quality. This study aims to determine the relationship between DSE and sleep quality.@*METHODS@#This study analyzed data of 50,250 wage workers from the fifth Korean Working Conditions Survey. Workers that did not respond or refused to answer any questions related to variables were excluded, and finally 36,709 participants were included in this study. A total of 2,287 workers (6.2%) were compared with non-DSE (34,422; 93.8%) workers, and multiple logistic regression analyses were applied.@*RESULTS@#DSE status had a significant association with difficulty falling asleep (odds ratio [OR]: 1.331, 95% confidence interval [CI]: 1.178–1.504), difficulty maintaining sleep (OR: 1.279; 95% CI: 1.125–1.455), and extreme fatigue after waking up (OR: 1.331; 95% CI: 1.184–1.496). A multiple logistic regression of the variables for sleep quality in DSE showed a significant association with exposure to physical factors for all types of poor sleep quality as well as shift work for difficulty maintaining sleep with extreme fatigue after waking up. Long working hours and emotional labor were also associated with extreme fatigue after waking up.@*CONCLUSIONS@#This study shows a significant association between DSE and poor sleep quality, especially when workers were exposed to physical risk factors (noise, vibration, abnormal temperature, etc.) and shift work.

Multidimensional sleep quality of dependent self-employment workers

BACKGROUND@#The number of workers in non-standard employment (NSE) is increasing due to industrial change and technological development. Dependent self-employment (DSE), a type of NSE, was created decades ago. Despite the problems associated with this new type of employment, few studies have been conducted on the effects by DSE on health, especially sleep quality. This study aims to determine the relationship between DSE and sleep quality.@*METHODS@#This study analyzed data of 50,250 wage workers from the fifth Korean Working Conditions Survey. Workers that did not respond or refused to answer any questions related to variables were excluded, and finally 36,709 participants were included in this study. A total of 2,287 workers (6.2%) were compared with non-DSE (34,422; 93.8%) workers, and multiple logistic regression analyses were applied.@*RESULTS@#DSE status had a significant association with difficulty falling asleep (odds ratio [OR]: 1.331, 95% confidence interval [CI]: 1.178–1.504), difficulty maintaining sleep (OR: 1.279; 95% CI: 1.125–1.455), and extreme fatigue after waking up (OR: 1.331; 95% CI: 1.184–1.496). A multiple logistic regression of the variables for sleep quality in DSE showed a significant association with exposure to physical factors for all types of poor sleep quality as well as shift work for difficulty maintaining sleep with extreme fatigue after waking up. Long working hours and emotional labor were also associated with extreme fatigue after waking up.@*CONCLUSIONS@#This study shows a significant association between DSE and poor sleep quality, especially when workers were exposed to physical risk factors (noise, vibration, abnormal temperature, etc.) and shift work.

Differences in the performance of health officers at the workplace according to their qualifications

BACKGROUND: Health officers are an integral part of the occupational health service, and there have been studies to identify and improve the role of health officers in the workplace in order to improve the level of health care in the workplace. This study aimed to determine the contribution of health officers to the role of a health officer as prescribed by law and the percentage of health management work performed during work according to their qualifications. METHODS: Questionnaires were distributed to a total of 4584 workplaces where health officers were hired, and a total of 806 copies (17.58%) were returned. Of these, 336 questionnaires were finally analyzed, after excluding questionnaires missing the main variables. Using the data, the difference of role contributions and the percentage of health care work performed during the whole day according to the qualification of the health officer was analyzed. RESULTS: Nurses were highly rated in the field of medical care, and industrial hygienists and air environmental engineers were highly rated in terms of chemicals and risk factor management. The percentage of health care work performed during the whole day differed according to the size of the workplace and industrial classification, but it was generally the lowest among air environmental engineers. CONCLUSIONS: Health officers play a very different role in the workplace depending on their qualification, and they need support for areas of other qualification. In order to effectively manage the health of the staff at a workplace, it is necessary to consider the development of a support system for small- and medium-sized enterprises and adjust the conditions of employment of the health officer according to the law.

The Association between Involuntary Smoking Exposure with Urine Cotinine Level and Blood Cadmium Level in General Non-Smoking Populations

Unintentional environmental exposure to toxicants is associated with an aggravated health status of the general population. Involuntary smoking (IS) exposure is one of the main routes to involuntary toxicants exposure. However, few studies have attempted to understand the environmental cadmium exposure by IS exposure in the general, non-smoking population. The purpose of the current study was to examine the relationship between blood cadmium level and IS level according to gender and age. We used the Korea National Health and Nutrition Examination Survey (KNHANES) IV–VI data that included heavy metal and urine cotinine sampling with IS exposure history. The final analysis comprised 3,493 adults (1,231 males and 2,262 females) and 395 adolescents (210 males and 185 females). Linear regression was performed to estimate the association between self-reported IS exposure with urine cotinine level and blood cadmium level in non-smokers with gender and age group stratification. In final regression model, the effect values (B) (standard errors [SE]) between blood cadmium and urine cotinine level in men was 0.0004 (0.0001) and 0.0006 (0.0002) in adults and adolescents, the B (SE) in women was 0.0006 (0.0002) and 0.0016 (0.0006) in adults and adolescents. Our study revealed, for the first time, a significant association between blood cadmium and IS exposure in non-smokers. Greater efforts are needed to improve environmental justices of the general population from IS, considering the severe harmful effects of involuntary exposure to even a low level of cadmium.

The Perceived Socioeconomic Status Is an Important Factor of Health Recovery for Victims of Occupational Accidents in Korea

We aimed to examine whether there is a correlation between the health recovery of industrial accident victims and their perceived socioeconomic status. Data were obtained from the first Panel Study of Worker's Compensation Insurance, which included 2,000 participants. We performed multivariate regression analysis and determined the odds ratios for participants with a subjectively lower socioeconomic status and for those with a subjectively lower middle socioeconomic status using 95% confidence intervals. An additional multivariate regression analysis yielded the odds ratios for participants with a subjectively lower socioeconomic status and those with a subjectively upper middle socioeconomic class using 95% confidence intervals. Of all participants, 299 reported a full recovery, whereas 1,701 did not. We examined the odds ratio (95% confidence intervals) for participants' health recovery according to their subjective socioeconomic status while controlling for sex, age, education, tobacco use, alcohol use, subjective state of health prior to the accident, chronic disease, employment duration, recovery period, accident type, disability status, disability rating, and economic participation. The odds of recovery in participants with a subjectively lower middle socioeconomic status were 1.707 times greater (1.264-2.305) than that of those with a subjectively lower socioeconomic status. Similarly, the odds of recovery in participants with a subjectively upper middle socioeconomic status were 3.124 times greater (1.795-5.438) than that of those with a subjectively lower socioeconomic status. Our findings indicate that participants' perceived socioeconomic disparities extend to disparities in their health status. The reinforcement of welfare measures is greatly needed to temper these disparities.

The Perceived Socioeconomic Status Is an Important Factor of Health Recovery for Victims of Occupational Accidents in Korea

We aimed to examine whether there is a correlation between the health recovery of industrial accident victims and their perceived socioeconomic status. Data were obtained from the first Panel Study of Worker's Compensation Insurance, which included 2,000 participants. We performed multivariate regression analysis and determined the odds ratios for participants with a subjectively lower socioeconomic status and for those with a subjectively lower middle socioeconomic status using 95% confidence intervals. An additional multivariate regression analysis yielded the odds ratios for participants with a subjectively lower socioeconomic status and those with a subjectively upper middle socioeconomic class using 95% confidence intervals. Of all participants, 299 reported a full recovery, whereas 1,701 did not. We examined the odds ratio (95% confidence intervals) for participants' health recovery according to their subjective socioeconomic status while controlling for sex, age, education, tobacco use, alcohol use, subjective state of health prior to the accident, chronic disease, employment duration, recovery period, accident type, disability status, disability rating, and economic participation. The odds of recovery in participants with a subjectively lower middle socioeconomic status were 1.707 times greater (1.264-2.305) than that of those with a subjectively lower socioeconomic status. Similarly, the odds of recovery in participants with a subjectively upper middle socioeconomic status were 3.124 times greater (1.795-5.438) than that of those with a subjectively lower socioeconomic status. Our findings indicate that participants' perceived socioeconomic disparities extend to disparities in their health status. The reinforcement of welfare measures is greatly needed to temper these disparities.

Facing Complaining Customer and Suppressed Emotion at Worksite Related to Sleep Disturbance in Korea

This study aimed to investigate the effect of facing complaining customer and suppressed emotion at worksite on sleep disturbance among working population. We enrolled 13,066 paid workers (male = 6,839, female = 6,227, age < 65 years) in the 3rd Korean Working Condition Survey (2011). The odds ratio (OR) and 95% confidence intervals (CI) for sleep disturbance occurrence were calculated using multiple logistic regression models. Among workers in working environments where they always engage complaining customers had a significantly higher risk for sleep disturbance than rarely group (The OR [95% CI]; 5.46 [3.43–8.68] in male, 5.59 [3.30–9.46] in female workers). The OR (95% CI) for sleep disturbance was 1.78 (1.16–2.73) and 1.63 (1.02–2.63), for the male and female groups always suppressing their emotions at the workplace compared with those rarely group. Compared to those who both rarely engaged complaining customers and rarely suppressed their emotions at work, the OR (CI) for sleep disturbance was 9.66 (4.34–20.80) and 10.17 (4.46–22.07), for men and women always exposed to both factors. Sleep disturbance was affected by interactions of both emotional demands (engaging complaining customers and suppressing emotions at the workplace). The level of emotional demand, including engaging complaining customers and suppressing emotions at the workplace is significantly associated with sleep disturbance among Korean working population.

Workplace Violence Experienced by Substitute (Daeri) Drivers and Its Relationship to Depression in Korea

Workplace violence is related to various health effects including mental illness such as anxiety or depression. In this study, the relationship between the experience of workplace violence and depression in substitute drivers in Korea, namely, daeri drivers, was investigated. To assess workplace violence, questions regarding types and frequency of the experience of violence over the past year were asked to the daeri drivers. In order to assess the risk of depression, the Center for Epidemiological Studies Depression Scale was used. Odds ratios with 95% confidence intervals of depression were estimated using multiple logistic regression analysis. All of the daeri drivers had experienced instance of verbal violence while driving and 66 of the drivers (34.1%) had been in such a situation more than once in the past quarter of a year. Sixty-eight daeri drivers (42.2%) had experienced certain type of physical violence over the past year. Compared to daeri drivers who had experienced workplace verbal violence less than 4 times and who had not experienced workplace physical violence over the past year, higher odds ratio was observed in daeri drivers who had experienced workplace verbal violence or physical violence, more than 4 times and more than one time respectively, after adjustment. Experience of verbal or physical type of workplace violence over the past year increased the risk of depression in the daeri drivers. Because violence against drivers can compromise the safety of the driver, the customer, and all the passengers, it is imperative that the safety and health of daeri drivers be highlighted.

Factors related to the physician and the employer influencing successful return to work in Korea: results from the first panel study of workers' compensation insurance (PSWCI)

OBJECTIVES: This study aims to investigate associated factors including the physician and the employer of successful return to work (RTW) in occupationally injured workers. METHODS: This study is based on the first panel study of workers' compensation insurance (PSWCI), published in June 2014. The PSWCI is a sample survey of occupationally injured workers who completed medical care in 2012 (89,921 people). A total of 2000 subjects were sampled based on sex, age, nine metropolitan-based regions, disability ratings, duration of rehabilitation, and whether vocational rehabilitation service was used. We divided the study population into two groups: return to work (RTW) group (job retention, reemployment, unpaid family worker, and self-employment), and non-RTW group (joblessness and economical inactivity). The odds ratios (ORs) and 95 % confidence intervals (CI) related to differences in basic characteristics, part of physician and employer-related factors between those who succeeded to RTW and those who did not were measured using multivariable logistic regression model. RESULTS: The success of RTW is 70.6 % (n = 1412) among participants. The ORs (95 % CI) of the participants belonging to RTW who received periodic recovery assessment from the medical care institution and the physician are 1.51 (1.07-2.13). The ORs (95 % CI) are 1.68 (1.05-2.69) for the RTW group who received work ability assessment and referral for vocational return. When the employer maintains the relationship with the occupationally injured worker, the worker has 1.39 times higher odds (95 % CI: 1.41-2.26) of the RTW group compared to the non-RTW group. CONCLUSIONS: The physician and the employer have a significant impact on the RTW.

The association between concealing emotions at work and medical utilization in Korea

OBJECTIVES: We aimed to investigate the association between concealing emotions at work and medical utilization. METHODS: Data from the 2007-2009 4th Korea National Health and Nutrition Examination Survey (KNHANES IV) was used, 7,094 participants (3,837 males, 3,257 females) aged between 20 and 54 who were economically active and completed all necessary questionnaire items were included. Odds ratios (ORs) and 95% confidence intervals (95% CI) for differences in hospitalization, outpatient visits, and pharmaceutical drug use between those who concealed their emotions and those who did not were investigated using logistic regression models with and without gender stratification. RESULTS: Among those who concealed their emotions (n = 2,763), 47.4% were females, and 50.1% had chronic disease. In addition, 9.7% of the concealing emotions group had been hospitalized within the last year, 24.8% had been outpatients in the last two weeks, and 28.3% had used pharmaceutical drugs in the last two weeks. All ORs represent the odds of belonging to the concealing emotions group over the non-concealing emotions group. After adjustment for individual, occupational, socioeconomic and disease factors, the adjusted ORs (95% CI) in hospitalization are 1.29 (1.08 ~ 1.53) in the total population, 1.25 (0.98 ~ 1.60) in males and 1.30 (1.02 ~ 1.66) in females, in outpatient visits are 1.15 (1.02 ~ 1.29) in the total population, 1.05 (0.88 ~ 1.24) in males and 1.25 (1.06 ~ 1.47) in females and in pharmaceutical drug use are 1.12 (1.01 ~ 1.25) in the total population, 1.08 (0.92 ~ 1.27) in males and 1.14 (0.98 ~ 1.33) in females. CONCLUSIONS: Those who concealed their emotions at work were more likely to use medical services. Moreover, the health effects of concealing emotions at work might be more detrimental in women than in men.