Association between precarious employment and the onset of depressive symptoms in men and women: a 13-year longitudinal analysis in Korea (2009-2022).

AIMS: Increasing social concern surrounds the potential adverse health effects of precarious employment (PE). In this study, we explored the association between PE and the onset of depressive symptoms. METHODS: A total of 11,555 Korean waged workers (5700 females) contributed 62,217 observations from 2009 to 2022. PE was operationalized as a multidimensional construct, including employment insecurity, income inadequacy and lack of rights and protection. Depressive symptoms were evaluated using the Center for Epidemiological Studies-Depression Scale (11-item version). The association between PE and the onset of depressive symptoms in the subsequent year was estimated using generalized estimating equations. Effect sizes were reported as odds ratio (OR) and 95% confidence interval (CI). RESULTS: The overall incidence of depressive symptoms was 8.3% during the study period. In cross-sectional analysis, daily employment, disguised employment, lower monthly wages and lack of social insurance coverage were associated with concurrent depressive symptoms in both men and women. Longitudinally, fixed-term employment (OR: 1.17, 95% CI: 1.07-1.29), daily employment (OR: 1.64, 95% CI: 1.45-1.85) and disguised employment (OR: 1.36, 95% CI: 1.17-1.57) were associated with the onset of depressive symptoms among the overall sample. Among men, the lowest quartiles of wage were associated with the onset of depressive symptoms (OR: 1.34, 95% CI: 1.13-1.60), while the absence of a trade union was associated among women (OR: 1.18, 95% CI: 1.01-1.39). CONCLUSIONS: Employment insecurity, inadequate income and lack of rights and protection may contribute to depressive symptoms. Therefore, PE serves as a significant social determinant of mental health among workers in Korea. Active policy efforts are warranted to improve the overall quality of employment in the workforce.

Long working hours, work-life imbalance, and poor mental health: a cross-sectional mediation analysis based on the sixth Korean Working Conditions Survey, 2020-2021.

Background There has been growing concern about the negative mental health impact of long working hours and overwork. Our study examined how work-life imbalance (WLI) could be a mediator between working hours and poor mental well-being.Methods We included 34,968 individuals from a nationwide cross-sectional survey in Korea. Self-reported working hours per week was collected, and mental health was assessed by the WHO-5 Well-Being Index. Counterfactual-based mediation models were employed to disentangle the total effects into a direct effect (work hour - poor mental health) and an indirect effect (work hour - WLI - poor mental health).Results Out of 34,968 participants, 52.6% worked 35-40 h/week, 20.0% worked 41-48 h/week, 11.7% worked 49-54 h/week, and 15.6% worked ≥55 h/week. The odds ratios (ORs) of the total impact of working hours on poor mental health were 1.08 (95% CI: 1.01-1.16) for 41-48 h/week, 1.28 (1.17-1.39) for 49-54 h/week, and 1.60 (1.48-1.74) for ≥55 h/week in comparison to 35-40 h/week. The ORs of the indirect effects were 1.04 (1.03-1.05) for 41-48 h/week, 1.08 (1.07-1.09) for 49-54 h/week, and 1.14 (1.12-1.16) for ≥55 h/week, accounting for 51%, 31%, and 28% of the total effects.Conclusion: Our findings suggest that WLI can partially mediate the association of long working hours with mental health deterioration. Policy efforts are required to mitigate the adverse mental health effects of overwork.

Relationship between long working hours and smoking behaviors: Evidence from population-based cohort studies in Korea.

OBJECTIVES: Long working hours and overwork are growing public health concerns in the Western-Pacific region. We explored the relationship between working hours and smoking behaviors of Korean workers. METHODS: This study included 284 782 observations (50 508 workers) from four nationwide cohort studies in Korea. Using generalized estimating equations, we estimated the associations of working hours with current smoking status, smoking initiation, and smoking cessation within each cohort. Cohort-specific estimates were combined through random-effect meta-analysis. Effect sizes were presented as odds ratios (OR) and 95 confidence intervals (CI). RESULTS: The overall smoking prevalence was 26.8% within the cohorts. The adjusted OR (95% CI) of the association between working hours and current smoking were 1.01 (0.94-1.08) for <35 hours/week, 1.04 (1.01-1.09) for 41-48 hours/week, 1.06 (1.01-1.10) for 49-54 hours/week, and 1.07 (1.04-1.10) for ≥55 hours/week compared with 35-40 hours/week. The adjusted OR (95% CI) of the association between working hours and smoking cessation in the follow-up were 0.93 (0.85-1.02) for <35 hours/week, 0.89 (0.83-0.96) for 41-48 hours/week, 0.87 (0.81-0.95) for 48-54 hours/week, and 0.91 (0.85-0.98) for ≥55 hours/week compared with 35-40 hours/week. No clear associations were observed between working hours and smoking initiation. CONCLUSION: Long working hours are associated with high current smoking risk and reduced likelihood of smoking cessation among Korean workers. Policy interventions are required to promote smoking cessation and reduce excess overwork for individuals experiencing long working hours.

Association between temporary employment and current smoking and change in smoking behaviors: A prospective cohort study from South Korea (2009-2018).

Background Previous studies have suggested that employment insecurity is associated with adverse health outcomes. We explored the association between temporary employment and smoking behaviors.Methods We analyzed 11,795 workers (51,867 observations) from the Korea Health Panel Study (2009-2018). Employment types were categorized as regular, fixed-term, or daily, based on the duration of labor contract. The outcomes were current smoking status and changes in smoking behavior (initiation or cessation) in the following year. Generalized estimating equations were used to estimate odds ratio (OR) and 95% confidence interval (CI).Results The proportions of fixed-term and daily workers were 41.2% and 16.4% for women and 23.6% and 12.4% for men, respectively. Temporary employment was associated with increased odds of current smoking, while also demonstrating prospective associations with changes in smoking behaviors. For instance, in prospective analyses, male workers with fixed-term and daily employments were associated with a decreased likelihood of smoking cessation (OR:0.77; 95% CI:0.65-0.91 for fixed-term employment and OR:0.66; 95% CI:0.52-0.83 for daily employment) in the following year compared to those with regular employment. Moreover, those experiencing consecutive temporary employment was most inversely associated with smoking cessation in both men (OR:0.56; 95% CI:0.44-0.71) and women (OR:0.37; 95% CI:0.16-0.85) compared to those experiencing consecutive regular employment. However, no clear association between temporary employment and smoking initiation was observed in both men and women.Conclusions Temporary employment is directly associated with current smoking and inversely associated with smoking cessation. Policies are needed to improve job insecurity among temporary employees.

A multiplex real-time RT-qPCR assay for simultaneous detection of porcine epidemic diarrhea virus, porcine deltacoronavirus, and swine acute diarrhea syndrome coronavirus.

Porcine epidemic diarrhea virus (PEDV), porcine deltacoronavirus (PDCoV), and swine acute diarrhea syndrome coronavirus (SADS-CoV) cause intestinal diseases with similar manifestations in suckling piglets. In this study, we developed a multiplex real-time PCR for differential diagnosis of PEDV, PDCoV, and SADS-CoV. The assay demonstrated high specificity with a detection limit of 5 copies/µl for each virus. The assay specifically detected PEDV, PDCoV, and SADS-CoV and excluded all other swine pathogens circulating in pigs. Furthermore, the assay exhibited satisfactory performance in analyzing clinical samples. The data indicate that the newly developed multiplex real-time PCR method can be applied for differential diagnosis of porcine enteric coronaviruses.

High-Reliability and Self-Rectifying Alkali Ion Memristor through Bottom Electrode Design and Dopant Incorporation.

Ionic memristor devices are crucial for efficient artificial neural network computations in neuromorphic hardware. They excel in multi-bit implementation but face challenges like device reliability and sneak currents in crossbar array architecture (CAA). Interface-type ionic memristors offer low variation, self-rectification, and no forming process, making them suitable for CAA. However, they suffer from slow weight updates and poor retention and endurance. To address these issues, the study demonstrated an alkali ion self-rectifying memristor with an alkali metal reservoir formed by a bottom electrode design. By adopting Li metal as the adhesion layer of the bottom electrode, an alkali ion reservoir was formed at the bottom of the memristor layer by diffusion occurring during the atomic layer deposition process for the Na:TiO2 memristor layer. In addition, Al dopant was used to improve the retention characteristics by suppressing the diffusion of alkali cations. In the memristor device with optimized Al doping, retention characteristics of more than 20 h at 125 °C, endurance characteristics of more than 5.5 × 105, and high linearity/symmetry of weight update characteristics were achieved. In reliability tests on 100 randomly selected devices from a 32 × 32 CAA device, device-to-device and cycle-to-cycle variations showed low variation values within 81% and 8%, respectively.

Association of precarious employment with depressive symptoms and suicidal ideation among female workers: Findings from a nationwide longitudinal study in Korea.

BACKGROUND: In this study, we examined the relationship of precarious employment (PE) with depressive symptoms and suicidal ideation among Korean women. METHODS: We included a nationwide sample of 4162 women drawn from the Korean Longitudinal Study of Women and Families, comprising 7566 observations. PE was assessed using three dimensions: employment insecurity, income inadequacy, and lack of rights and protection. Depressive symptoms were assessed using the 10-item version of the Center for Epidemiological Studies Depression Scale. Generalized estimating equations were used to estimate the association between each element of PE and the depressive symptoms and suicidal ideation over a two-year follow-up period, represented as odds ratios (ORs) and confidence intervals (CIs). RESULTS: The overall prevalence rates of depressive symptoms and suicidal ideation were 11.8 % and 1.9 %, respectively. Compared with permanent employment, fixed-term employment (OR [95 % CI]:1.29 [1.00-1.67]) or daily employment (OR [95 % CI]:1.53 [1.26-1.99]) was associated with the depressive symptoms at the follow-up. Additionally, lack of social benefits (OR [95 % CI]:1.40 [1.09-1.79]) and high perceived vulnerability (OR [95 % CI]:1.27 [1.08-1.49]) were associated with the depressive symptoms at the follow-up. Additionally, daily employment was associated with the suicidal ideation at the follow-up (OR [95 % CI]:1.94 [1.02-3.68]) and high perceived vulnerability was marginally associated with an increased suicidal ideation risk (OR [95 % CI]:1.49 [0.98-2.29]). LIMITATION: Causal effect of PE could not be asserted due to the observational nature of this study. CONCLUSIONS: PE is a social determinant of women's mental health and policy interventions are required to improve their employment conditions.

Association between long working hours and diet quality and patterns: A latent profile analysis of a nationally representative sample of Korean workers.

BACKGROUND: Long working hours are associated with cardiovascular and metabolic diseases. This study investigated the relationship between the working hours and dietary qualities and patterns in Korean workers. METHODS: Data from 24,523 workers were extracted from the Korea National Health and Nutrition Examination Survey, 2013-2021. The Korean Healthy Eating Index (KHEI), which ranges from 0 to 100, with a higher score indicating greater adherence to Korean dietary guidelines and superior dietary quality, was used for dietary assessment. We identified dietary patterns and classified workers using latent profile analysis. Logistic regressions were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: Five distinct dietary patterns emerged: healthy diet (24.8%), low-vegetable diet (14.0%), average diet (7.8%), low-fruit diet (31.4%), and poor diet (22.0%). The mean KHEI score was 60.8, with the highest score observed in the healthy diet pattern (71.3) and the lowest, in the poor diet pattern (50.0). Compared with working 35-40 h/week, working ≥55 h/week was negatively associated with KHEI scores (ß: -1.08; 95% CI: -1.67, -0.49). Those working ≥55 h/week were less likely to have a healthy diet pattern (OR: 0.81; 95% CI: 0.72, 0.91) and more likely to have a low-fruit diet (OR: 1.36; 95% CI: 1.20, 1.55) or poor diet pattern (OR: 1.23; 95% CI: 1.05, 1.43) compared with those working 35-40 h/week. CONCLUSION: Long working hours are associated with undesirable dietary quality and patterns. Policy interventions aimed at enhancing dietary quality are needed to alleviate the health burdens associated with long working hours.

Clinical and radiological features of malformed mesiodens in the nasopalatine canal: an observational study.

OBJECTIVES: The purpose of this study is to investigate the morphological changes that occur when mesiodens is located within the nasopalatine canal, as well as clinical characteristics. METHODS: Clinical records and CT images of patients who had mesiodens in the nasopalatine canal were retrospectively analysed. In addition to demographic information, clinical symptoms and complications associated with extraction of mesiodens were recorded. Using CT images, number, location, size, and tooth morphology were evaluated. RESULTS: This study included 32 patients and 38 mesiodens within the nasopalatine canal. Supernumerary teeth exhibited a characteristic feature of thin and elongated shape in the canal (narrow width and elongation were observed in 96.6% and 53.3% of the patients, respectively). Fusion was found in 4 patients and dilaceration in 12. A complication occurred in 2 patients, which was tooth remnant, not a neurologic complication. Only 5 mesiodens could be detected in the nasopalatine canal on panoramic images. CONCLUSIONS: Morphological abnormalities in mesiodens within the nasopalatine canal were frequently detected, and these could be effectively diagnosed through 3D imaging analysis.

Association between long working hours and the development of suicidal ideation among female workers: An 8-year population-based study using the Korean Longitudinal Survey of Women & Family (2012-2020).

Long working hours and overwork have recently emerged as pressing public health concerns. We explored the association between long working hours and suicidal ideation in female workers. A total of 8017 women (24,331 observations) from the fourth to eighth waves of the Korean Longitudinal Survey of Women and Families (2012-2020) were analyzed. To address the repeated measurements within each participant, we employed a generalized estimating equation to estimate the odds ratio (OR) and 95% confidence intervals (CIs). The prevalence of suicidal ideation was 1.9% for those working 35-40 h/week and 4.4% for those working ≥55 h/week. Compared to individuals working 35-40 h/week, those working ≥55 h/week were more likely to experience concurrent suicidal ideation (OR [95% CI]:1.85 [1.43-2.39]). The OR (95% CI) of the association between long working hours and onset of suicidal ideation in the subsequent wave was 1.69 (1.20-2.38) for ≥55 h/week. In subgroup analysis, this association was pronounced among workers with low-income levels (OR [95% CI]: 1.97 [1.29-3.02]) and blue-collar occupations (OR [95% CI]: 2.27 [1.41-3.66]). Policy efforts are required to protect the mental health of female workers exposed to long working hours.

Association between long working hours and engagement in preventive healthcare services in Korean workers: Findings from the Korean National Health and Nutrition Examination Survey.

BACKGROUND: Engagement in preventive healthcare services is crucial for preventing diseases. We explored how working hours are associated with engagement in preventive healthcare services, with a focus on gender differences. METHODS: This cross-sectional study used data from the 2007-2012 Korean National Health and Nutrition Examination Survey. The dependent variable was engagement in each of the five preventive healthcare services (health check-ups, influenza vaccination, and stomach, breast, and cervical cancer screenings). We estimated the prevalence ratios (PRs) and 95% confidence intervals (CIs) using robust Poisson regression. RESULTS: The study analyzed 19,819 workers (9119 women). The adjusted PRs (95% CI) of the association between working ≥55 h per week and engagement in preventive healthcare services among men were 0.95 (0.90-1.00) for health check-ups, 0.86 (0.77-0.96) for influenza vaccination, and 0.95 (0.87-1.03) for stomach cancer screening compared to working 35-40 h per week. Among women, the adjusted PRs (95% CI) of the association between working ≥55 h per week and engagement in preventive healthcare services were 0.84 (0.78-0.91) for health check-ups, 0.82 (0.73-0.92) for influenza vaccination, and 0.88 (0.80-0.97) for stomach, 0.85 (0.78-0.94) for breast, and 0.82 (0.74-0.91) for cervical cancer screenings. CONCLUSION: Long working hours were negatively associated with engagement in preventive healthcare services, and the association was pronounced among female workers. Efforts to promote preventive healthcare participation among individuals with long working hours are necessary, and it is essential to consider the unique vulnerabilities of women when developing such policies.

Performance pressure and mental health among finance workers in Korea: a cross-sectional study.

Objectives: While issues related to mental health, including suicide, have been frequently reported among finance workers, no formal investigation has been undertaken. This study was conducted to analyze correlations between indicators of performance pressure, which is a characteristic of the finance sector, and mental health. Methods: An online survey was administered to 1,181 participants. Brief questionnaires were employed to ask general questions about participant characteristics, work environment, and the presence of performance pressure, suicidal thoughts/plans/attempts, depression (indicated by the Patient Health Questionnaire-9), and anxiety (measured with the Generalized Anxiety Disorder-7). Frequency analysis, chi-square testing, and multivariate logistic regression analysis were performed. Results: Of the 1,181 respondents, 797 (83.54%) reported feeling pressure to perform at work, while 252 (26.42%) admitted to occasional willingness to achieve results even through illegal activities. Multivariate logarithmic regression analysis was employed to examine the correlation between performance pressure and mental health. This analysis revealed that those expressing willingness to achieve. Results: through illegal activities exhibited higher levels of suicidal ideation (adjusted odds ratio [aOR], 1.63; 99% confidence interval [CI], 1.04-2.55), plans (aOR, 1.75; 99% CI, 1.01-3.01), and attempts (aOR, 2.72; 99% CI, 1.06-6.98). Additionally, these individuals demonstrated higher levels of depression (aOR, 2.02; 99% CI, 1.34-3.06) and anxiety (aOR, 2.84; 99% CI, 1.81-4.46). Conclusion: Performance pressure is prevalent within the finance industry. This pressure serves as a major source of stress for employees and is evident in 3 representative indicators of mental health: suicide, depression, and anxiety.

Origin of minicircular mitochondrial genomes in red algae.

Eukaryotic organelle genomes are generally of conserved size and gene content within phylogenetic groups. However, significant variation in genome structure may occur. Here, we report that the Stylonematophyceae red algae contain multipartite circular mitochondrial genomes (i.e., minicircles) which encode one or two genes bounded by a specific cassette and a conserved constant region. These minicircles are visualized using fluorescence microscope and scanning electron microscope, proving the circularity. Mitochondrial gene sets are reduced in these highly divergent mitogenomes. Newly generated chromosome-level nuclear genome assembly of Rhodosorus marinus reveals that most mitochondrial ribosomal subunit genes are transferred to the nuclear genome. Hetero-concatemers that resulted from recombination between minicircles and unique gene inventory that is responsible for mitochondrial genome stability may explain how the transition from typical mitochondrial genome to minicircles occurs. Our results offer inspiration on minicircular organelle genome formation and highlight an extreme case of mitochondrial gene inventory reduction.

Occupational risk factors associated with lower urinary tract symptoms among female workers: a systematic review.

A systematic review was performed aiming to identify the various occupational risk factors of lower urinary tract symptoms (LUTS) among female workers. A systematic, comprehensive literature search of PubMed, Embase and Cochrane Library databases was conducted to identify studies published until 24 November 2021, evaluating the possible occupational risk factors of LUTS among female workers. Two reviewers assessed all articles retrieved through a computerised search for eligibility using predetermined criteria. Data on the first author, publication year, country, study design, participants, identified occupational risk factors, outcome variables and main results were extracted from the selected articles. The Newcastle-Ottawa Quality Assessment Scale guidelines were adopted to estimate the quality scores. Overall, our search yielded a total of 16 articles suitable for review. The occupational risk factors identified in the studies were strenuous physical demand and activity, prolonged sitting, occupational stress, shift work, limited use of the toilet at work and other occupational environments (eg, an unclean and uncomfortable workplace, dangerous job and probability of accidents, feeling pressed for time and awkward position for long periods). The findings of this review may raise awareness regarding the risk of LUTS among female workers with these factors. From an occupational health perspective, the implementation of tailored prevention strategies based on these occupational factors may prevent female workers from developing LUTS. PROSPERO registration number CRD42022316728.

Association of paternal cadmium and other heavy metal exposure to birth outcomes using propensity score matching.

BACKGROUND: Human exposure to cadmium has various effects on health, especially on male reproductive organs. Although it is widely known that prenatal maternal cadmium exposure can affect birth outcomes, the effect of paternal exposure to cadmium remains unclear. OBJECTIVES: This study aimed to evaluate the effect of paternal cadmium exposure on fetal growth by considering maternal cadmium exposure and exposure to other heavy metals, namely mercury and lead. METHODS: The Mothers and Children's Environmental Health (MOCEH) study is a prospective birth cohort study in Korea. Overall, 1313 families (father-mother-child triple) without child abnormalities and who completed paternal whole blood cadmium assessments were included in this study. Families were divided into two subgroups based on the blood sampling periods, namely early and late pregnancy. Subjects were selected as follows: one family triple with a high level of paternal cadmium and two triples with low levels of paternal cadmium, using the method of propensity score matching. And linear regression analyses were performed. RESULTS: The group with high paternal cadmium exposure (80% or more; 1.93 µg/L) had lower birth weight infants compared to the group with low cadmium concentrations (ß(se) = -0.21(0.10); p-value = 0.0283). After stratification by infant sex, prenatal paternal cadmium exposure significantly reduced the birth weight of females in subgroups of different sampling times, namely early pregnancy (ß(se) = -0.52 (0.22); p-value = 0.0170) and late pregnancy (ß(se) = -0.43 (0.18); p-value = 0.0160). Finally, after performing propensity score matching in the early pregnancy measurement group, it was found that the prenatal exposure of father to cadmium significantly reduced birth weight in females (ß(se) = -0.72(0.25); p-value = 0.0047). CONCLUSION: This study assessed the effect of paternal cadmium exposure on birth outcomes in family units consisting of a father, mother, and child. Prenatal paternal cadmium exposure negatively affected birth weight, especially that of female, considering covariates and other heavy metals exposure, namely mercury and lead.

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.

Association between long working hours and liver enzymes: evidence from the Korea National Health and Nutrition Examination Survey, 2007-2017.

Background: Long working hours causes several health risks, but little is known about its effects on the liver. This study aimed to examine the correlation between working hours and abnormal liver enzyme levels. Methods: We used data from the Korea National Health and Nutrition Examination Survey IV-VII. For the final 15,316 study participant, the information on working hours was obtained through questionnaires, and liver enzyme levels, consisting of serum levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT), through blood tests. The relationship between weekly working hours and abnormal levels of liver enzymes was analyzed using multiple logistic regression, and a trend test was also conducted. Results: In male, working ≥ 61 hours per week was significantly associated with elevated AST and ALT levels compared with working 35-52 hours per week. Even after adjusting for covariates, the odds ratios (ORs) of abnormal AST and ALT increased by 1.51 (95% confidence interval: 1.20-2.05) and 1.25 (1.03-1.52), respectively, and a dose-response relationship was observed. This association was more prominent among the high-risk group, such as those aged > 40 years, obese individuals, worker on non-standard work schedule, pink-collar workers, or temporary worker. No correlation was observed in female. Conclusions: Long working hours are associated with abnormal liver function test results in male. Strict adherence to statutory working hours is necessary to protect workers' liver health.

Development of a multiplex PCR assay for the simultaneous detection of big blue octopus (Octopus cyanea), giant Pacific octopus (Enteroctopus dofleini), and common octopus (Octopus vulgaris).

Since octopuses are similar in appearance and can be processed into various forms, seafood fraud has been reported. In this study, we developed the PCR assay to simultaneously detect three octopuses (big blue octopus, giant Pacific octopus, and common octopus). Specific primer sets were designed based on COI gene. We observed that the specific PCR amplicon sizes were 84 bp for big blue octopus, 117 bp for giant Pacific octopus, and 166 bp for common octopus, respectively. This assay was then used to test for specificity and did not show cross-reactivity with 15 cephalopods families. The limit of detection of the multiplex PCR assay was 0.1 pg. Subsequently, 30 commercial food products were then monitored to evaluate the applicability of this assay. All products were specifically amplified, and three octopus species of interest were distinguished. Therefore, this assay can be used as an octopus authentication tool in the seafood industry.

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.

Multiplex PCR Assay for Simultaneous Identification of Five Types of Tuna (Katsuwonus pelamis, Thunnus alalonga, T. albacares, T. obesus and T. thynnus).

There is a need to identify the species of similar types of fish, especially those that are commercially sold. Particularly, the price of tuna varies depending on its type, which is difficult to determine as they are sold in cut or processed forms. This study developed a multiplex polymerase chain reaction (PCR) assay to identify the five most common tuna species: bigeye, skipjack, Atlantic bluefin, albacore, and yellowfin tunas. Newly designed species-specific primer sets for these five tuna species were created. Subsequently, the amplicon sizes obtained were 270, 238, 200, 178, and 127 base pairs for bigeye, skipjack, Atlantic bluefin, albacore, and yellowfin tunas, respectively. Each primer's specificity was further tested using 15 other fish species, and no cross-reactivity was observed. To identify multiple targets in a single reaction, multiplex PCR was optimized to increase its resolution and accuracy. The detection levels of the multiplex PCR assay were confirmed to be 1 pg for all the five tunas. Additionally, it was successfully applied to 32 types of commercial tuna products. Therefore, this multiplex PCR assay could be an efficient identification method for various tuna species.