Drawing Guideline for JKMS Manuscripts (05): Plots for Numeric Data

The appropriate plot effectively conveys the author’s conclusions to the readers. Journal of Korean Medical Science will provide a series of special articles to show you how to more easily make consistent and excellent plots. In this article, we will cover plots with numeric data.

Macakurzin C Derivatives as a Novel Pharmacophore for Pan-Peroxisome Proliferator-Activated Receptor Modulator

The natural flavonoid macakurzin C (1) exhibited adiponectin biosynthesis-inducing activity during adipogenesis in human bone marrow mesenchymal stem cells and its molecular mechanism was directly associated with a pan-peroxisome proliferator-activated receptor (PPAR) modulator affecting all three PPAR subtypes α, γ, and δ. In this study, increases in adiponectin biosynthesisinducing activity by macakurzin C derivatives (2–7) were studied. The most potent adiponectin biosynthesis-inducing compound 6, macakurzin C 3,5-dimethylether, was elucidated as a dual PPARα/γ modulator. Compound 6 may exhibit the most potent activity because of the antagonistic relationship between PPARδ and PPARγ. Docking studies revealed that the O-methylation of macakurzin C to generate compound 6 significantly disrupted PPARδ binding. Compound 6 has therapeutic potential in hypoadiponectinemia-related metabolic diseases.

Optimal drain management following complicated laparoscopic cholecystectomy for acute cholecystitis: a propensity-matched comparative study

Purpose@#This study was performed to investigate the effect of drain placement on complicated laparoscopic cholecystectomy (cLC) for acute cholecystitis (AC). @*Methods@#This single-center retrospective study reviewed patients with AC who underwent cLC between January 2010 and December 2020. cLC was defined as open conversion, subtotal cholecystectomy, adjacent organ injury during surgery, operation time of ≥90 minutes, or estimated blood loss of ≥100 mL. One-toone propensity score matching was performed to compare the surgical outcomes between patients with and without drain on cLC. @*Results@#A total of 216 patients (mean age, 65.8 years; 75 female patients [34.7%]) underwent cLC, and 126 (58.3%) underwent intraoperative abdominal drainage. In the propensity score-matched cohort (61 patients in each group), early drain removal (≤postoperative day 3) was performed in 42 patients (68.9%). The overall rate of surgical site infection (SSI) was 10.7%. Late drain removal demonstrated significantly worse surgical outcomes than no drain placement and early drain removal for overall complications (13.1% vs. 21.4% vs. 47.4%, p = 0.006), postoperative hospital stay (3.8 days vs. 4.4 days vs. 12.7 days, p < 0.001), and SSI (4.9% vs. 11.9% vs. 31.6%, p = 0.006). In the multivariate analysis, late drain removal was the most significant risk factor for organ space SSI. @*Conclusion@#This study demonstrated that drain placement is not routinely recommended, even after cLC for AC. When placing a drain, early drain removal is recommended because late drain removal is associated with a higher risk of organ space SSI.

Effects and safety of COVID-19 vaccination on assisted reproductive technology and pregnancy: A comprehensive review and joint statements of the KSRM, the KSRI, and the KOSAR / 대한생식의학회지

Humanity is in the midst of the coronavirus disease 2019 (COVID-19) pandemic, and vaccines—including mRNA vaccines—have been developed at an unprecedented speed. It is necessary to develop guidelines for vaccination for people undergoing treatment with assisted reproductive technology (ART) and for pregnancy-related situations based on the extant laboratory and clinical data. COVID-19 vaccines do not appear to adversely affect gametes, embryos, or implantation; therefore, active vaccination is recommended for women or men who are preparing for ART. The use of intravenous immunoglobulin G (IVIG) for the treatment of immune-related infertility is unlikely to impact the effectiveness of the vaccines, so COVID-19 vaccines can be administered around ART cycles in which IVIG is scheduled. Pregnant women have been proven to be at risk of severe maternal and neonatal complications from COVID-19. It does not appear that COVID-19 vaccines harm pregnant women or fetuses; instead, they have been observed to deliver antibodies against severe acute respiratory syndrome coronavirus 2 (SARSCoV-2) to the fetus. Accordingly, it is recommended that pregnant women receive COVID-19 vaccination. There is no rationale for adverse effects, or clinical cases of adverse reactions, in mothers or neonates after COVID-19 vaccination in lactating women. Instead, antibodies to SARS-CoV-2 can be delivered through breast milk. Therefore, breastfeeding mothers should consider vaccination. In summary, active administration of COVID-19 vaccines will help ensure the safe implementation of ART, pregnancy, and breastfeeding.

Correlational Analysis of Bone Health Status and Vitamin D-Related Biomarkers in Women Working in Agriculture

Objective@#The purpose of this study was to investigate the status of bone health in women working in agriculture and analyze the associations between bone health and various vitamin D-related biomarkers. @*Methods@#This observational study enrolled women working in agriculture (n = 210) and control occupations (n = 180). The concentration of serum total 25-hydroxy vitamin D [25(OH)D] was measured using the Elecsys Vitamin D Total Kit, and serum vitamin D-binding protein (VDBP) was measured by enzyme-linked immunosorbent assay (ELISA). Along with albumin, 25(OH)D and VDBP were used to calculate the concentrations of bioavailable and free 25(OH)D. Bone mineral density (BMD) and T-score were measured at lumbar 1–4 and the femur neck using dual-energy X-ray absorptiometry. To identify factors affecting BMD, log-linear model and linear regression analysis were performed for statistical analysis. @*Results@#Agricultural women workers showed higher serum concentrations of bioavailable 25(OH)D (12.8 ± 3.7 vs. 8.7 ± 5.1 ng/mL) and lower VDBP concentrations (201.8 ± 45.0 vs. 216.0 ± 68.2 μg/ mL) than control women. The association between these two vitamin D related-biomarkers and femur neck BMD were confirmed through univariable and multivariable linear model analysis. Although lumbar BMD did not differ between groups, the agricultural group displayed a lower femur BMD and a 4.3-fold increase in the risk of osteoporosis compared with the control group. @*Conclusions@#Women working in agriculture showed lower femur BMD than the control group. Of the vitamin D-related biomarkers tested, bioavailable 25(OH)D and VDBP were associated with BMD. As bioavailable 25(OH)D levels are affected mainly by VDBP levels, VDBP may play a role in the lower femur neck BMD values observed in the agricultural group. Thus, the measurement of VDBP concentration might be considered a simple and non-invasive method for measuring bone health status.

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.

Efficacy of sentinel lymph node biopsy with radioisotope alone and the prediction of sentinel node status using PET-CT in breast cancer

Purpose@#Sentinel lymph node biopsy (SLNB) using both a radioactive isotope (RI) and blue dye is considered highly effective; however, there were limitations with the use of both agents in some hospitals, and blue dye has been shown to have some adverse effects. Additionally, preoperative prediction of sentinel lymph node (SLN) status using the maximum standardized uptake value (SUVmax) on positron emission tomography-computed tomography (PET-CT) can help avoid unnecessary axillary dissection or SLNB. Thus, we evaluated the efficacy and oncologic safety of SLNB using an RI alone in terms of long-term outcomes and determined the association between SLN metastasis and SUVmax of the primary tumor. @*Methods@#This retrospective study was conducted at Konyang University Hospital between March 2011 and May 2018. Overall, 142 patients with breast cancer who underwent SLNB using an RI alone were enrolled. Data on identification and false-negative rates were collected. The SUVmax of primary tumors on PET-CT were analyzed for their association with SLN metastasis. @*Results@#The identification and false-negative rates were 98.6% and 0%, respectively. There was no axillary local recurrence in patients with negative SLN findings. The correlation between the SUVmax of the primary tumor and SLN status was significant (r=0.249, P=0.005); the cutoff value for negative SLN metastasis was <2.15. @*Conclusion@#The single agent method using an RI is not inferior to other methods and serves as a feasible option for SLNB. And the number of excised SLNs could be minimized when the SUVmax of primary tumor is extremely low.

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.

Efficacy of sentinel lymph node biopsy with radioisotope alone and the prediction of sentinel node status using PET-CT in breast cancer

Purpose@#Sentinel lymph node biopsy (SLNB) using both a radioactive isotope (RI) and blue dye is considered highly effective; however, there were limitations with the use of both agents in some hospitals, and blue dye has been shown to have some adverse effects. Additionally, preoperative prediction of sentinel lymph node (SLN) status using the maximum standardized uptake value (SUVmax) on positron emission tomography-computed tomography (PET-CT) can help avoid unnecessary axillary dissection or SLNB. Thus, we evaluated the efficacy and oncologic safety of SLNB using an RI alone in terms of long-term outcomes and determined the association between SLN metastasis and SUVmax of the primary tumor. @*Methods@#This retrospective study was conducted at Konyang University Hospital between March 2011 and May 2018. Overall, 142 patients with breast cancer who underwent SLNB using an RI alone were enrolled. Data on identification and false-negative rates were collected. The SUVmax of primary tumors on PET-CT were analyzed for their association with SLN metastasis. @*Results@#The identification and false-negative rates were 98.6% and 0%, respectively. There was no axillary local recurrence in patients with negative SLN findings. The correlation between the SUVmax of the primary tumor and SLN status was significant (r=0.249, P=0.005); the cutoff value for negative SLN metastasis was <2.15. @*Conclusion@#The single agent method using an RI is not inferior to other methods and serves as a feasible option for SLNB. And the number of excised SLNs could be minimized when the SUVmax of primary tumor is extremely low.

Relationship of Bone Mineral Density and Knee Osteoarthritis (Kellgren-Lawrence Grade):Fifth Korea National Health and Nutrition Examination Survey

Background@#Osteoarthritis (OA) and osteoporosis (OP) are the 2 most common bone disorders associated with aging. We can simply assume that older patients have a higher incidence of OA and OP with more severity. Although several papers have conducted studies on the relationship between OA and OP, none of them has demonstrated a conclusive link. In this study, we used radiological knee OA and bone mineral density (BMD; T-score of the total hip and lumbar spine) to analyze the incidence of OA and OP in a large population. We aimed to determine the relationship between OA and OP and investigate the associated risk factors. @*Methods@#This cross-sectional study used data extracted from the 2010–2012 Korea National Health and Nutrition Examination Survey. We evaluated a total of 4,250 participants aged ≥ 50 years who underwent knee radiography and dual-energy X-ray absorptiometry and their laboratory results. The relationship between radiological knee OA and BMD was assessed. The generalized linear model was used to evaluate the relationship between BMD and Kellgren-Lawrence (KL) grade. @*Results@#The higher KL grade was associated with older age, higher body mass index (BMI), female sex, and lower hemoglobin level (p 0.05). After adjusting for confounding factors (age, BMI, diabetes, hypertension, smoking, and alcohol consumption), the average T-scores of total hip and lumbar spine were the highest in the mild OA group with KL grade 2 (–0.22 ± 1.08 and –0.89 ± 1.46, respectively,p < 0.001). The average T-scores of the total hip and lumbar spine significantly decreased as OA progressed from moderate (KL grade 3; –0.49 ± 1.05 and –1.33 ± 1.38, respectively, p < 0.001) to severe (KL grade 4; –0.73 ± 1.13 and –1.74 ± 1.75, respectively, p < 0.001). T-scores of the moderate-to-severe OA group were significantly lower than those of the non-OA group (KL grades 0 and 1, p < 0.001). @*Conclusions@#Compared with the non-OA group, BMD (T-scores of the total hip and lumbar spine) was higher in the mild OA group and lower in the moderate-to-severe OA group.

The Usefulness of Preoperative Colonoscopic Tattooing with Autologous Blood for Localization in Laparoscopic Colorectal Surgery

Purpose@#In colorectal cancer surgery, it is important to have accurate resection margins. However, it is challenging to localize lesions during laparoscopy. Therefore, to reduce surgical errors, many preoperative localizing methods have been introduced. In this study, we aimed to assess the preoperative feasibility and safety of autologous blood tattooing. @*Methods@#A total of 11 patients underwent preoperative colonoscopic autologous blood tattooing from August 2017 to February 2020. At the start of the surgery, the surgeon assessed the patients for the precision of visibility and other complications such as abscess or spillage. The patients’ characteristics, outcomes, and complications were collected retrospectively. @*Results@#The study comprised 8 men and 3 women, with an average age of 63 years. Ten patients showed precise visibility, and no localization errors were observed during surgery. No complication was observed in all patients. @*Conclusion@#Preoperative autologous blood tattooing is a very useful and safe technique because it has high visibility with no complications. This method does not require additional agents or facilities. A large-scale study will be required to develop standard guidelines.

Which Patients Are a Better Candidate of Laparoscopic Repair in Obturator Hernia Patients?

Purpose@#Obturator hernia is a difficult disease to diagnose. If a surgical treatment is delayed in obturator hernia, a bowel resection may be required due to strangulation. The surgical treatment of this disease is to use a classical laparotomy. Recently, the laparoscopic approach has been reported and reviewed for efficiency. We checked the indicators that determine the most appropriate surgical method according to the patient’s condition. @*Methods@#In the study, a single-institution, retrospective analysis of surgical patients undergoing an obturator hernia surgery between 2003 and 2018 was performed. The patients were divided into a laparoscopic group (5 patients underwent laparoscopic repair; no intestinal resection) and an open group (13 patients who underwent open repair; 10 with and 3 without intestinal resection). The outcomes were compared between the groups. We analyzed the relevant factors that could predict the proper method of surgery. @*Results@#A total 18 patients were included in the study. All patients were female, with body mass index (BMI) of under 21 kg/m2. Of the various factors, only the WBC and CRP counts were the factors that had shown significant differences between the two groups. It is noted that patients with open surgery had a higher WBC counts (10406 versus 6520/μl; p=0.011) and CRP counts (7.84 vs. 0.32 mg/dl; p=0.027). @*Conclusion@#Obturator hernia can be treated with a laparoscopic surgery. The choice of surgical treatment can be considered in advance through the review of the patient’s WBC count or CRP count.

Diallyl Biphenyl-Type Neolignans Have a Pharmacophore of PPARα/γ Dual Modulators

Adiponectin secretion-promoting compounds have therapeutic potentials in human metabolic diseases. Diallyl biphenyl-type neolignan compounds, magnolol, honokiol, and 4-O-methylhonokiol, from a Magnolia officinalis extract were screened as adiponectin-secretion promoting compounds in the adipogenic differentiation model of human bone marrow mesenchymal stem cells (hBM-MSCs). In a target identification study, magnolol, honokiol, and 4-O-methylhonokiol were elucidated as PPARα and PPARγ dual modulators. Diallyl biphenyl-type neolignans affected the transcription of lipid metabolism-associated genes in a different way compared to those of specific PPAR ligands. The diallyl biphenyl-type neolignan structure provides a novel pharmacophore of PPARα/γ dual modulators, which may have unique therapeutic potentials in diverse metabolic diseases.

Multidimensional sleep quality of dependent self-employment workers

Anxiety, Depression and Sleep Disturbance among Customer-Facing Workers

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 25-hydroxy vitamin D and vitamin D-binding protein concentrations according to the severity of endometriosis / 대한생식의학회지

OBJECTIVE: To investigate serum 25-hydroxyl vitamin D (25(OH)D) and vitamin D-binding protein (VDBP) concentrations in women with endometriosis according to the severity of disease. METHODS: Women with mild endometriosis (n = 9) and advanced endometriosis (n = 7), as well as healthy controls (n = 16), were enrolled in this observational study. Serum total 25(OH)D concentrations were analyzed using the Elecsys vitamin D total kit with the Cobas e602 module. Concentrations of bioavailable and free 25(OH)D were calculated. Concentrations of VDBP were measured using the Human Vitamin D BP Quantikine ELISA kit. Variables were tested for normality and homoscedasticity using the Shapiro-Wilk test and Leven F test, respectively. Correlation analysis was used to identify the variables related to total 25(OH)D and VDBP levels. To assess the effects of total 25(OH)D and VDBP levels in the three groups, multivariate generalized additive modeling (GAM) was performed. RESULTS: Gravidity and parity were significantly different across the three groups. Erythrocyte sedimentation rate (ESR) and CA-125 levels increased as a function of endometriosis severity, respectively (p= 0.051, p= 0.004). The correlation analysis showed that total 25(OH)D levels were positively correlated with gravidity (r = 0.59, p< 0.001) and parity (r = 0.51, p< 0.003). Multivariate GAM showed no significant relationship of total 25(OH)D levels with EMT severity after adjusting for gravidity and ESR. However, the coefficient of total 25(OH)D levels with gravidity was significant (1.87; 95% confidence interval, 0.12–3.63; p= 0.040). CONCLUSION: These results indicate that vitamin D and VDBP levels were not associated with the severity of endometriosis.

Analysis of vitamin D-binding protein (VDBP) gene polymorphisms in Korean women with and without endometriosis / 대한생식의학회지

OBJECTIVE: Vitamin D-binding protein (VDBP) mediates various biological processes in humans. The goal of this study was to investigate whether VDBP gene polymorphisms could predispose Korean women to endometriosis. METHODS: We prospectively enrolled women with endometriosis (n = 16) and healthy controls (n = 16). Total serum 25-hydroxyl vitamin D (25(OH)D) concentrations were measured using an Elecsys vitamin D total kit. Levels of bioavailable and free 25(OH)D were calculated. Concentrations of VDBP were measured using a vitamin D BP Quantikine ELISA kit. DNA was extracted using a DNeasy blood & tissue kit. Two single-nucleotide polymorphisms (SNPs; rs4588 and rs7041) in GC, the gene that codes for VDBP, were analyzed using a TaqMan SNP genotyping assay kit. The functional variant of VDBP was determined based on the results of the two SNPs. RESULTS: Gravidity and parity were significantly lower in the endometriosis patients than in the control group, but serum CA-125 levels and the erythrocyte sedimentation rate were significantly higher. Total serum 25(OH)D levels in the endometriosis patients were significantly lower than in the control group. However, serum bioavailable 25(OH)D, free 25(OH)D, and VDBP levels did not differ significantly between the endometriosis and control groups. The genotypes and allele frequencies of GC were similar in both groups. CONCLUSION: Korean women with endometriosis had lower total serum 25(OH)D concentrations than controls. Neither serum VDBP concentrations nor polymorphisms in the gene coding for VDBP were associated with endometriosis. Further studies are needed to investigate the pathophysiology and clinical implications of 25(OH)D and VDBP in endometriosis.

Association between shift work and hyperhomocysteinemia in male workers

BACKGROUND: Shift work is associated with a higher risk of cardiovascular diseases. Here, we sought to assess the relationship between shift work and plasma homocysteine levels. Determining the correlations between shift work and homocysteine levels may provide a better understanding of the mechanisms underlying cardiovascular diseases. METHODS: This study was performed using data from routine health examinations of steel workers in 2017. In total, 431 male workers (70 daytime workers and 361 shift workers) employed on a rolling departure schedule were recruited. Plasma homocysteine levels > 15 μmol/L were considered elevated. The χ2, analysis of variance, and multiple logistic regression analyses were used to examine the association between shift work and plasma homocysteine levels. RESULTS: In comparison to daytime workers, the odds ratio (OR) of hyperhomocysteinemia in individuals with < 10 years of shift work was 1.14 (95% confidence interval [CI]: 0.64–2.03), compared to 2.01 (95% CI: 1.14–3.54) for workers with ≥ 10 years of experience. After adjusting for confounding variables, the adjusted OR for shift workers with < 10 years of experience was 0.95 (95% CI: 0.50–1.80), compared to 2.00 (95% CI: 1.07–3.74) for workers with ≥ 10 years of experience. CONCLUSIONS: The risk of hyperhomocysteinemia was significantly higher in shift workers compared to those working normal daytime hours, particularly among long-term shift workers.

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.