Systematic review and meta-analysis of the association between long working hours and hypertension risk.

BACKGROUND: Hypertension, a major public health problem worldwide, has been linked to lifestyle factors and work conditions, with conflicting evidence on the association between long work hours and risk of hypertension. METHODS: We conducted a systematic review and meta-analysis of observational studies to investigate the relationship between working hours and hypertension or blood pressure, assessed the risk of bias and performed subgroup analyses. The protocol was registered with the International Prospective Register of Systematic Reviews. RESULTS: The pooled OR for the association between long working hours and risk of hypertension was 1.09 (95% CI: 0.88 to 1.35) in the 15 studies that used hypertension as the outcome. In the three studies that used blood pressure as the outcome, diastolic blood pressure was higher among those with long working hours compared with those with non-long working hours (1.24 mm Hg, 95% CI: 0.19 to 2.29). In subgroup analysis, the pooled OR for the association between long working hours and risk of hypertension was 1.28 (95% CI: 1.14 to 1.44) and 1.00 (95% CI: 0.64 to 1.56) in women and men, respectively. CONCLUSIONS: Although this study could not clearly confirm the relationship between long working hours and hypertension, the subgroup analysis suggests that long working hours may be associated with hypertension, particularly among women. More reliable research is needed to establish causality. PROSPERO REGISTRATION NUMBER: CRD42023406961.

Occupational Characteristics and Health Status of Vietnamese Male Migrant Workers in the Republic of Korea.

Background: The objective of this study is to identify the working conditions and health status of Vietnamese male migrant workers in Republic of Korea, in comparison to the Korean general population. Methods: We conducted our survey through the Migrant People Center, and we received completed questionnaires from 87 male Vietnamese migrant workers. The questionnaire employed was identical to those used in the Korean Working Conditions Survey and the 2020 Korea National Health and Nutrition Examination Survey. The collected data from the Vietnamese migrant workers was then compared with the Korean reference population using indirect age-standardization. Results: Vietnamese male workers demonstrated a higher prevalence of health problems including hearing problems (age-standardized prevalence ratio (aSPR) 13.22, 95% confidence interval [CI]: 8.07-20.4), skin problems (aSPR 13.49, 95% CI: 8.07-20.4), and low back pain (aSPR 8.40, 95% CI: 6.50-10.69). Elevated exposure to workplace hazards such as chemicals (aSPR 2.36, 95% CI: 1.51-3.51), organic solvents (aSPR 2.22, 95% CI: 1.44-3.28), handling of heavy objects (aSPR 1.67, 95% CI: 1.24-2.21), and high temperatures (aSPR 1.96, 95% CI: 1.46-2.57) was observed among them. Additionally, they faced a higher risk of no personal protective equipment (aSPR 2.53, 95% CI: 1.26-4.52) and a greater prevalence of unmet medical needs (aSPR 7.14, 95% CI: 4.74-10.32). Conclusion: Our findings highlight the elevated workplace hazards, health problems, and unmet medical needs among Vietnamese male workers compared to the Korean reference population. These findings underscores the urgency for enhanced scrutiny over working conditions and protective equipment provision, coupled with efforts to improve healthcare accessibility and worker education.

Who is the most precarious among the nonstandard workers? A comparative study of unmet medical needs among standard workers and subtypes of nonstandard workers.

OBJECTIVE: Nonstandard workers might have a relatively higher risk of unmet medical needs than standard workers. This study subdivided nonstandard workers to investigate the effects of nonstandard employment on unmet medical needs. METHODS: We used the Korea Health Panel 2011-2018 data. The independent variable, employment contract, was defined using the nonstandard form described by the ILO: Temporary workers, Part-time workers, and Temporary agent workers. The analytical method used in this study was a panel logit model that accounted for repeated measured participants. By controlling for time-invariant individual-fixed effects, we investigate the relationship between subdivided nonstandard work and the risk of unmet medical needs with reference to standard work. RESULTS: The results of the analysis clearly showed that compared with standard workers, temporary agency workers had a significantly higher risk of unmet medical needs (Odds ratio = 1.182, 95% CI = 1.016-1.374). The main cause of this phenomenon was economic reasons in this group. CONCLUSIONS: This study found that temporary agency workers in the general Korean population have a significantly higher risk of unmet healthcare needs. The result of this study implies that financial hardship might be a fundamental health hazard among workers with nonstandard employment.

Association of summer temperatures and acute kidney injury in South Korea: a case-crossover study.

BACKGROUND: Due to climate change, days with high temperatures are becoming more frequent. Although the effect of high temperature on the kidneys has been reported in research from Central and South America, Oceania, North America and Europe, evidence from Asia is still lacking. This study aimed to examine the association between short-term exposure to high temperatures and acute kidney injury (AKI) in a nationwide study in South Korea. METHODS: We used representative sampling data from the 2002-2015 National Health Insurance Service-National Sample Cohort in South Korea to link the daily mean temperatures and AKI cases that occurred in the summer. We used a bidirectional case-crossover study design with 0-7 lag days before the emergency room visit for AKI. In addition, we stratified the data into six income levels to identify the susceptible population. RESULTS: A total of 1706 participants were included in this study. The odds ratio (OR) per 1°C increase at 0 lag days was 1.051, and the ORs per 1°C increase at a lag of 2 days were both 1.076. The association between exposure to high temperatures and AKI was slightly greater in the low-income group (OR = 1.088; 95% CI: 1.049-1.128) than in the high-income group (OR = 1.065; 95% CI: 1.026-1.105). CONCLUSIONS: In our study, a relationship between exposure to high temperatures and AKI was observed. Precautions should be taken at elevated temperatures to minimize the risk of negative health effects.

The Relationship between Hospital Selection by Employer and Disabilities in Occupational Accidents in Korea.

Background: In the event of an industrial accident, the appropriate choice of hospital is important for worker health and prognosis. This study investigates whether the choice of hospital by the employer in the case of industrial accidents affects the prognosis of injured employees. Methods: Data from the 2018 Panel Study of Workers' Compensation Insurance in Korea were used in an unmatched case-controlled study. The exposure variable is "hospital selection by an employer," and the outcome variable is 'worker's disability." Odds ratios (ORs) were estimated by modified Poisson regression and adjusted for age, gender, underlying disease, injury severity, and workplace size and stratified by industrial classification. The group at increased risk was analyzed and stratified by age, gender, and area. Results: In the construction industry, hospital selection by the employer was significantly associated with increased risk of disability (adjusted OR 1.26; 95% confidence interval [CI]: 1.20-1.32) and severe disability (adjusted OR 1.38; 95% CI: 1.08-1.76) among the injured. Female and younger workers not living in the Seoul capital area were more at risk of disability and severe disability than those living in the Seoul capital area. Conclusions: Hospital selection by employers affects the prognosis of workers injured in an industrial accident. For protecting workers' health and safety, workplace emergency medical systems should be improved, and the selection of appropriate hospitals to supply treatment should be reviewed.

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.

The Association Between Long Working Hours of Parents and Dyslipidemia in Their Children.

The purpose of our study is to examine the association between children's low-density lipoprotein cholesterol (LDL-C) levels and their parents' working hours. We used data from the 2010-2018 Korea National Health and Nutrition Examination Survey in which lipid profile samples of 3,799 children were eligible. Logistic regression analyses were used with an outcome variable of the dichotomous LDL-C group and an exposure variable of the father's and mother's working hours, respectively. In logistic regression models adjusted for age, sex, household income, education level of children and parents, and working hours of the parents, mothers' working hours more than 52 h per week were significantly associated with their children's dyslipidemia [OR 2.14, 95% confidence interval (CI) 1.33-3.47] compared to working 40 h or less, whereas fathers' working hours did not show statistical significance (OR 1.08, 95% CI 0.71-1.66) in the same manner. The association was greatest for elementary school students for mothers working more than 52 h per week (OR 3.42, 95% CI 1.64-7.14) compared to those working hours 40 h per week or less. Mothers' long working hours were associated with a higher prevalence of dyslipidemia in their children. The association was strongest for elementary school students. Proper working time of parents is required for their children's health.

Association between Obesity and Anemia in a Nationally Representative Sample of South Korean Adolescents: A Cross-Sectional Study.

Anemia is associated with physical, cognitive, and developmental problems. Given that there are limited studies on anemia prevalence among obese Asian adolescents and that past evidence is controversial, this study investigated the relationship between obesity and anemia in a nationally representative sample of South Korean adolescents. Data were obtained from the 2007-2019 Korea National Health and Nutrition Examination Survey. Overall, 10,231 subjects were included in the analysis. Multiple logistic regression was performed to determine the relationship between obesity and anemia. Compared with the non-obesity group, the adjusted odds ratio (OR; 95% confidence interval [CI]) of anemia was 1.00 (0.66-1.50) in the obesity group. However, in the early adolescent subgroup of 10-13 years (adjusted OR, 2.88; 95% CI, 1.20-6.95), the risk of anemia was significantly higher in the obese group than in the non-obese group. Obesity was associated with an increased risk of anemia in early adolescents. Obese adolescents aged 10-13 require special care, especially through regular examination and management for anemia.

Premenstrual syndrome incidence rate and risk factors among the working population in the Republic of Korea: a prospective cohort study.

BACKGROUND: Premenstrual syndrome (PMS) is the most common disease of the genitourinary tract in women. Although a sizeable proportion of women have symptoms or diagnosed PMS, its etiology remains unclear. The purpose of this cohort is to offer incidence and relevant risk factors of PMS among reproductive-aged Korean female workers. METHODS: Cohort data used were from the National Health Insurance Service-Female Employees (from 2007 to 2015) conducted by the NHIS. A total of 121,024 female workers were analyzed to estimate the incidence and hazard ratio of PMS. PMS data was based on information obtained from medical facility visits during an eight-year follow-up. RESULTS: The incidence of PMS was 7.0% during follow-up periods. In industrial classification, human health and social work activities have the highest incidence (9.0%) of PMS. Cumulative incidence of PMS has continuously increased by approximately 1% annually for eight years. Adjusted hazard ratio with 95% confidence interval was significantly higher in the 15-19 years old age group (2.81, 95%CI 2.35-3.36), manual worker (1.06, 95%CI 1.01-1.12), with anemia (1.13, 95%CI 1.06-1.20), and underweight (1.21, 95%CI 1.10-1.25) compared to those in the reference group. CONCLUSION: This study describes the PMS status with trend and risk factors using follow-up design among women under a middle-aged working population. Further study is warranted for better understanding on the risk factors of PMS for reproductive-aged female workers.

Association between Rheumatoid Arthritis and Poor Self-Perceived Oral Health in Korean Adults.

BACKGROUND AND OBJECTIVE: Rheumatoid arthritis (RA) and oral health problems have been reported as specific disease units; however, this study was conducted to evaluate the association between RA and comprehensive oral health status. Therefore, this study aimed to assess the association between RA and oral health using self-perceived oral health (SPOH) variables that can determine the oral health status in Korean adults using representative national data. METHODS: Data from 40,186 selected participants were collected from the Korea National Health and Nutrition Examination Survey (KNHANES) between 2007 and 2018. The prevalence relative risk (PRR) was estimated using Poisson regression analysis to obtain the risk ratio of the SPOH according to RA. RESULTS: The risk of SPOH depending on the RA status was statistically significant (odds ratio [OR] = 1.108, 95% confidence interval [CI] 1.005-1.222). In addition, the risk of SPOH depending on the RA status was higher in the group with diabetes mellitus (DM) (OR = 1.205, 95% CI 0.966-1.503) than in the group without DM (OR = 1.088, 95% CI 0.976-1.214). CONCLUSIONS: In this study, a significant association was identified between RA and SPOH. Oral health experts should identify the factors affecting the oral health of patients with RA and provide correct oral health care; however, additional research is needed.

Comparative analyses of occupational injuries among temporary agency worker and direct contract workers: Findings from the Korea Health Panel 2009-2018.

OBJECTIVES: Several studies have reported health or safety risk of temporary agency workers (TAW). Since most of the studies are just cross-sectional studies, we intended to identify the risk of occupational injury in TAW, using longitudinal study design. METHODS: The Korea Health Panel 2009-2018 data were used in the study. For the statistical analysis of this study, we used a panel logit model to identify the risk of occupational injury in TAW compared to direct contract workers (DCW). RESULTS: There was no significant difference in risk of occupational injury between TAW and DCW among the overall population (adjusted OR 0.920, 95% CI 0.600-1.411). However, there was a significant increase in occupational injury in women (adjusted OR 2.134, 95% CI 1.092-4.170) and the "19-34" age group (adjusted OR 2.744, 95% CI 1.103-6.825) of TAW. CONCLUSIONS: This study provides evidence for vulnerable groups such as women and younger age groups in the relationship between TAW and occupational injury.

Long Working Hours and Risk of Depression by Household Income Level: Findings From the Korea National Health and Nutrition Examination Survey (KNHANES).

OBJECTIVES: To investigate the relationship between working hours and the risk of depression according to household income level. METHODS: We used the data from the Korea National Health and Nutrition Examination Survey. The information on working hours was obtained from the questionnaire, and depression was assessed by The Patient Health Questionnaire-9. After stratifying by household income level, the risk of depression for long working hour group (more than or equal to 52 hours a week), compared with the 30 to 51 working hour group as a reference, were calculated using multiple logistic regression. RESULTS: It was found that long working hours associated with high risk for depression in the group with the highest income, but not in the group with the lowest income. CONCLUSIONS: The relationship between long working hours and the risk of depression varied by household income level.

Association of sedentary work with colon and rectal cancer: systematic review and meta-analysis.

OBJECTIVES: There has been no research on sedentary behaviour in the occupational domain that occupies a large portion of the daily life. METHODS: We conducted a meta-analysis to investigate the association between sedentary work and colorectal cancer. We searched PubMed, Embase and Cochrane databases up to 12 August 2020 for peer-reviewed journal articles that assessed the association between sedentary work and colon or rectal cancer. Pooled estimates of ORs were obtained using random effects models. Statistical tests for publication bias, heterogeneity and sensitivity analysis were applied. RESULTS: Of the 5 381 studies initially identified, 23 studies with 64 reports were eligible for inclusion. Sedentary work significantly increased the risk of colon cancer (pooled OR=1.21, 95% CI 1.11 to 1.31, p value ≤0.0001) and rectal cancer (pooled OR=1.08, 95% CI 1.00 to 1.16, p value=0.0395). The adjustment for leisure time physical activity attenuated the association and made the risk estimates non-significant for sedentary behaviour, but the association was independent of sex, control of body mass index and assessment of sedentary behaviour. CONCLUSIONS: We found evidence of association between sedentary work and the risk of colon or rectal cancer. Limiting excessive sedentary work could be an important means of preventing colon and rectal cancer.

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.

Effect of Noise on Sleep and Autonomic Activity in Children according to Source.

BACKGROUND: Noise has been a major issue in children due to its effect on emotional symptoms and sleep problems. The present study investigated the effect of noise on sleep and autonomic activity in children according to three variables, namely, road traffic noise, aircraft noise, and noise sensitivity (NS). METHODS: The study is epidemiological in nature. A total of 474 subjects of four elementary schools were evaluated in conjunction with the 2014 noise map data gathered from two metropolitan regions, Seoul and Ulsan, in South Korea. Each subject completed the children's sleep habits questionnaire, and heart rate variability (HRV) was recorded. Analysis of covariance was performed using monthly income as a covariate. RESULTS: Aircraft noise was associated with night waking (P = 0.047), whereas no significant association was observed between sleep and road traffic noise. After stratifying by NS, no significant results were obtained for road traffic noise. However, high levels of aircraft noise in the high-NS group were associated with high degrees of bedtime resistance (P = 0.049). In terms of HRV, no significant difference was observed in the results between groups. CONCLUSION: Road traffic noise did not significantly alter sleep or autonomic activity in children, whereas aircraft noise exerted a negative effect on sleep. The findings suggest that the impact of noise on sleep in children varies depending on noise sources.

Shift Work and Dry Eye Disease in the Korean Working Population: A Population-Based Cross-Sectional Study.

This study aimed to evaluate the association between shift work and dry eye disease (DED) in the general population. The 2011 Korea Health Panel (KHP) was used. Chi-square test and multivariate logistic regression were used to assess the relationship between shift work and DED. Stratification analysis was conducted by sex and age. Overall, the odds ratio (OR) of DED according to shift work did not showed significant results (adjusted OR = 1.230, 95% CI 0.758-1.901). When findings were stratified based on age older or younger than 40 years, the OR of DED increased to 2.85 (95% CI: 1.25-5.90) in shift workers under 40 years of age. Our results show an association between shift work and DED in a group of younger subjects.

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 age-standardized 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.

Impact of preoperative factors on recovery of continence after artificial urinary sphincter implantation in postprostatectomy incontinence.

BACKGROUND: The purpose of this study was to determine the influence of preoperative factors on the recovery of continence after artificial urinary sphincter (AUS) implantation in postprostatectomy incontinence. MATERIALS AND METHODS: Seventy-two patients who underwent AUS implantation between April 2006 and March 2020 were analyzed. The clinical features and preoperative urodynamic parameters were correlated with the postoperative continence rate using linear and logistic regression analysis. The recovery of continence was defined by the patient requiring no use of a protective urine pad during the 24 hours. RESULTS: Of the 72 patients, 57 (79.2%) recovered continence (dry group), while 15 (20.8%) were wearing more than 1 pad per day (wet group) on the last follow-up visit. In the clinical characteristics, only the interval between radical prostatectomy and AUS (in months) showed a statistically significant difference (35.4 ± 26.2 in the dry group, 22.7 ± 12.2 in the wet group, p = 0.009). Other preoperative clinical features such as the underlying disease, surgical methods, size of prostate, tumor stage, and radio nor hormonal therapy did not present statistically significant differences.Of the preoperative urodynamic parameters, only the abdominal leak point pressure (ALPP) showed statistical significance when related to surgical outcomes by 88.6 ± 33.6 in the dry group and 66.1 ± 29.6 in wet the group (P = 0.024). The number of patients for whom ALPP was higher than 80 cm H2O was 61.4% in the dry group and 20% in the wet group (95% confidence interval: 1.612-25.11). Other preoperative UDS features including detrusor underactivity, maximum urethral closure pressure, and others were not statistically significant. CONCLUSIONS: The interval between RP and AUS, as well as the preoperative ALPP, can be possible predictive factors for the surgical outcomes of AUS implantation. In addition, an ALPP of >80 cm H2O has a high degree of predictability for success of AUS surgical outcomes in post-RP incontinence.

Relationship Between Emotional Labor and Perceived Health Status Among Service and Sales Workers: Findings From the Korea National Health and Nutrition Examination Survey 2007 to 2009.

OBJECTIVES: This study examined the relationship between emotional labor and general health status in a nationally representative sample of South Korean service and sales workers. METHODS: Data were obtained from the 2007 to 2009 Korea National Health and Nutrition Examination Survey. A total of 1907 subjects were included in the analysis. Multiple logistic regression was performed to determine the relationship between emotional labor and perceived health status (PHS). RESULTS: The adjusted odds ratio (95% confidence interval) of poor PHS was 1.869 (1.464 to 2.391) among high emotional labor group, compared with the low emotional labor group as the reference. Perceived stress accounted for 35.57% of the variance in the relationship between high emotional labor and poor PHS. CONCLUSIONS: Emotional labor was associated with increased risk of poor PHS.

The Health Status of Informal Waste Collectors in Korea.

Background: A broad, holistic approach was performed among informal waste collectors (IWCs) in Korea to understand their complex multidimensional health and safety problems. Methods: In the quantitative study, a survey of IWCs was conducted at four junk shops in Gangbuk-gu, Seoul, and survey data were used to calculate age-standardized prevalence rates based on comparisons with the general population in Korea. A qualitative study was also performed to provide more details on IWCs' occupational and musculoskeletal injuries and depression. Results: In the quantitative study, the age-standardized prevalence rate (aSPR) of occupational injury was higher than that of the general standard population (aSPR: 10.42, 95% confidence interval (CI) 5.19-18.64) and that of blue-collar workers (aSPR: 4.65, 95% CI 2.32-8.32). Regarding musculoskeletal problems, compared to employed populations, the aSPRs of shoulder pain (aSPR: 2.63, 95% CI 1.60-4.06), wrist pain (aSPR: 3.33, 95% CI 1.33-6.86), knee pain (aSPR: 1.51, 95% CI 1.01-2.17), and ankle pain (aSPR: 3.54, 95% CI 1.14-8.26) were higher. Regarding psychological problems, depression (aSPR: 2.55, 95% CI 1.27-4.56) and suicidal or self-harm ideation (aSPR: 2.09, 95% CI 1.11-3.58) were higher compared to general populations. Through the qualitative study and case study on muscular problems, more details on the work environment problems of IWCs were obtained. Conclusions: IWCs are exposed to various occupational hazards and lack proper protection. They show a high prevalence of occupational injury, musculoskeletal disease, and depression.