Background: To analyze the effects of socioeconomic status (type of insurance and income level) and cancer stage on the survival of patients with liver cancer in Korea. Methods: A retrospective cohort study was constructed using data from the Healthcare Big Data Platform project in Korea between January 1, 2007, and December 31, 2017. A total of 143,511 patients in Korea diagnosed with liver cancer (International Classification of Diseases, 10th Revision [ICD-10] codes C22, C220, and C221) were followed for an average of 11 years. Of these, 110,443 died. The patient’s insurance type and income level were used as indicators of socioeconomic status. Unadjusted and adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using a Cox proportional hazards regression model to analyze the relationship between the effects of sex, age, and cancer stage at first diagnosis (Surveillance, Epidemiology, and the End Results; SEER), type of insurance, and income level on the survival of patients with liver cancer. The interactive effects of the type of insurance, income level, and cancer stage on liver cancer death were also analyzed. Results: The lowest income group (medical aid) showed a higher risk for mortality (HR (95% CI); 1.37 (1.27–1.47) for all patients, 1.44 (1.32–1.57) for men, and 1.16 (1.01–1.34) for women) compared to the highest income group (1–6) among liver cancer (ICD-10 code C22) patients. The risk of liver cancer death was also higher in the lowest income group with a distant cancer stage (SEER = 7) diagnosis than for any other group. Conclusion Liver cancer patients with lower socioeconomic status and more severe cancer stages were at greater risk of death. Reducing social inequalities is needed to improve mortality rates among patients in lower social class groups who present with advanced cancer.

Purpose: This study aimed to examine the interrupting effect of social distancing (SD) on emergency department (ED) patients with ischemic heart disease (IHD), stroke, asthma, and suicide attempts by PM 2.5 exposure in eight Korean megacities from 2017 to 2020. Materials and Methods: The study used National Emergency Department Information System and AirKorea data. A total of 469014 patients visited EDs from 2017 to 2020. Interrupted time series analysis was employed to examine changes in the level and slope of the time series, relative risk, and confidence intervals (CIs) by PM 2.5 exposure. The SD level was added to the sensitivity analysis. Results: The interrupted time series analysis demonstrated a significant increase in the ratio of relative risk (RRR) of IHD patients in Seoul (RRR=1.004, 95% CI: 1.001, 1.006) and Busan (RRR=1.007, 95% CI: 1.002, 1.012) post-SD. Regarding stroke, only patients in Seoul exhibited a significant decrease post-SD (RRR=0.995, 95% CI: 0.991, 0.999). No significant changes were observed for asthma in any of the cities. In the case of suicide attempts, Ulsan demonstrated substantial pre-SD (RR=0.827, 95% CI: 0.732, 0.935) and post-SD (RRR=1.200, 95% CI: 1.057, 1.362) differences. Conclusion While the interrupting effect of SD was not as pronounced as anticipated, this study did validate the effectiveness of SD in modifying health behaviors and minimizing avoidable visits to EDs in addition to curtailing the occurrence of infectious diseases.

Background: To investigate the effect of parental social class on cancer mortality in children under 5 in Korea, two birth cohorts were constructed by linking national birth data to under-5 death data from the Statistics Korea for 1995–1999 (3,323,613 births) and 2010–2014 (2,297,876 births). Methods: The Cox proportional hazards model adjusted for covariates was used in this study. Results: Social inequalities of under-5 cancer mortality risk in paternal education and paternal employment status were greater in 2010–2014 than in 1995–1999. The gap of hazard ratio (HR) of under-5 cancer mortality between lower (high school or below) and higher (university or higher) paternal education increased from 1.23 (95% confidence interval, 1.041.46) in 1995–1999 to 1.45 (1.11–1.97) in 2010–2014; the gap of HR between parents engaged in manual work and non-manual work increased from 1.32 (1.12–1.56) in 1995–1999 to 1.45 (1.12–1.89) in 2010–2014 for fathers, and from 1.18 (0.7–1.98) to 1.69 (1.03–2.79) for mothers. When the parental social class was lower, the risk of under-5 cancer mortality was higher in not only adverse but normal births. Conclusion Social inequalities must be addressed to reduce the disparity in cancer mortality of children under 5 years old.

Background: Conventional modality requires several days observation by Holter monitor to differentiate atrial fibril‑ lation (AF) between Paroxysmal atrial fibrillation (PAF) and Non-paroxysmal atrial fibrillation (Non-PAF). Rapid and practical differentiating approach is needed. Objective: To develop a machine learning model that observes 10-s of standard 12-lead electrocardiograph (ECG) for real-time classification of AF between PAF versus Non-PAF. Methods: In this multicenter, retrospective cohort study, the model training and cross-validation was performed on a dataset consisting of 741 patients enrolled from Severance Hospital, South Korea. For cross-institutional validation, the trained model was applied to an independent data set of 600 patients enrolled from Ewha University Hospital, South Korea. Lasso regression was applied to develop the model. Results: In the primary analysis, the Area Under the Receiver Operating Characteristic Curve (AUC) on the test set for the model that predicted AF subtype only using ECG was 0.72 (95% CI 0.65–0.80). In the secondary analysis, AUC only using baseline characteristics was 0.53 (95% CI 0.45–0.61), while the model that employed both baseline characteris‑ tics and ECG parameters was 0.72 (95% CI 0.65–0.80). Moreover, the model that incorporated baseline characteristics, ECG, and Echocardiographic parameters achieved an AUC of 0.76 (95% CI 0.678–0.855) on the test set. Conclusions Our machine learning model using ECG has potential for automatic differentiation of AF between PAF versus Non-PAF achieving high accuracy. The inclusion of  Echocardiographic parameters further increases model per‑ formance. Further studies are needed to clarify the next steps towards clinical translation of the proposed algorithm.

Background: This study aimed to establish a strategy to improve the poor working environment and working conditions among long-term healthcare workers in Korea. Methods: A total of 600 questionnaires with which long-term health care workers participated in the targeted base areas of each city and province nationwide were distributed directly and 525 responses were collected and 506 responses were analyzed. Surveys, on-site field visits, and in-depth interviews were also conducted to understand the working environment as well as conditions and establish a strategy for improving the working environment among long-term healthcare workers to understand the demands of working conditions and working conditions. Results: Korean long-term care workers firstly and mostly enumerated their risk factors for ill-health when lifting or moving elderly recipients directly by hand (69.9%), followed by increased physical workload with old beds, tools, and facilities (42.3%) in the workplaces, shortage of manpower (32%), and source of infection (30%). To improve the working environment as well as conditions, Korean long-term care workers considered improving low-wage structures, ergonomic improvements to solve excessive physical loads, and increasing various bonus payments as well as implementing the salary system, positive social awareness, and increasing resting time. Of 506 responses, 92.3% replied that the long-term care insurance system for the elderly should be developed to expand publicization at the national level. Conclusion This study proposes to improve the low-wage structure of Korean long-term care workers, automation and improvement of facilities, equipment, and tools to eliminate excessive physical loads (beneficiary elderly lifting), and reduction of night labor.

Purpose: This study aims to explore income-based disparities in breast cancer (BC) incidence and stage at presentation in a national population in South Korea, where a National Cancer Screening Program (NCSP) has been implemented. Methods: In 2007, new patients with BC were identified using the Korea Central Cancer Registry database. We calculated adjusted odds ratios (aORs) to evaluate the association between individual income level and the risk of distant stage BC at presentation, adjusting for women’s age, body mass index, disability registration, employment, region of residence, and year of diagnosis. Results: The cumulative age-standardized incidence of BC in the 11 years was highest among women in the richest quintile (2,040 per 100,000 women for 11 years), whereas the proportion of distant stage at presentation was the highest (10.2%) among the medical aid beneficiaries. The aOR of distant stage diagnosis at presentation was higher for lowerincome quintiles, and the risk was the highest in the medical aid beneficiaries (aOR, 2.25;95% confidence interval, 1.97–2.58) than in the richest quintile. The income-based gradient in aORs for distant stage did not differ between younger (< 40 years) and older patients. Conclusion A higher risk of distant stage BC at presentation among the lower-income and medical aid groups in the context of a NCSP was observed. A more focused approach toward women in lower-income groups is necessary to alleviate the disparity in the risk of advanced BC.

Objectives: We aimed to identify the factors related to depression and quality of life in patients with hypertension by using multilevel regression analysis. Methods: In 2019, 229 043 participants in the Korean Community Health Survey were selected as the study group. Individual factors were identified using data from the 2019 Community Health Survey. Regional factors were identified using data from the National Statistical Office of Korea. Multilevel regression analysis was conducted to find individual and local factors affecting depression and quality of life in patients with hypertension and to determine any associated interactions. Results: As individual factors in patients with hypertension, women, those with lower education-levels, recipients of basic livelihood benefits, and those with poor dietary conditions showed stronger associations with depression and quality of life. As regional factors and individual-level variables in patients with hypertension, lower gross regional personal income, fewer doctors at medical institutions, and lower rates of participation in volunteer activities presented stronger associations with depression and quality of life. In addition, the associations of depression with gross regional personal income, the number of doctors at medical institutions, and dietary conditions were significantly stronger in patients with hypertension than in patients without hypertension. The associations of gender and employment status with quality of life were also significantly greater. Conclusions Policy interventions are needed to adjust health behaviors, prevent depression, and improve quality of life for patients with hypertension, especially for those with the risk factors identified in this study.

Purpose: We explored the role of parental social class in preterm birth (PTB) and low birth weight (LBW) in association with child mortality in Korea. Materials and Methods: A total of 7,302,732 births in Korea between 1995 and 2007 were used for designing the national retrospective cohort study. Kaplan-Meier survival curves and Cox proportional hazard models were used to determine the risk of child death after adjusting for covariates. Results: Parental social class was associated with adverse birth outcomes and child mortality in Korea. Parental social class increased the strength of the relationship of adverse birth outcomes with child mortality. Child mortality was higher among PTB and LBW infants from parents with a lower social class than normal births from parents with a higher social class. In particular, the disparity in child mortality according to parental social class was greater for LBW and PTB than intrauterine growth retardation births.When one of the parents had a middle-school education or lower, the disparity in child mortality due to adverse birth outcomes was large regardless of the other spouse’s educational status. Inactive economic status for the father, as well as an occupation in manual labor by the mother, increased the risk of child mortality. Conclusion Strong relationships for social inequalities and adverse birth outcomes with inequalities in child mortality in South Korea were found in this study. Tackling social inequalities, as well as reducing adverse birth outcomes, are needed to reduce the disparities in child mortality in South Korea.

Purpose: Thrombotic stroke is a type of ischemic stroke characterized by motor dysfunction and memory impairments. In the present study, the effect of treadmill exercise on motor function and short-term memory was evaluated in relation with synaptic plasticity in the mice with photothrombotic stroke. Methods: Photothrombotic stroke was induced by cortical photothrombotic vascular occlusion. The mice in the treadmill exercise groups performed running on a motorized treadmill for 28 days. Motor function was determined using rota-rod test and foot fault test. Step-through avoidance task was conducted to evaluate short-term memory. Immunohistochemistry for 5-bromo-2′-deoxyuridine and doublecortin was conducted to detect new cell generation. Postsynaptic density protein 95, synaptophysin, brain-derived neurotrophic factor (BDNF), and tyrosine kinase B receptor (TrkB) were determined using western blot. The number of dendritic spines was determined using Golgi stain. Results: Treadmill exercise improved motor function and short-term memory in mice with the photothrombotic stroke. The infarct size was reduced and the number of dendritic spines and expression of postsynaptic density protein 95 and synaptophysin in the peri-infarct cortex and hippocampus were increased by treadmill exercise in photothrombotic stroke mice. Treadmill exercise enhanced neurogenesis through increasing the expression of the hippocampal BDNF and TrkB in photothrombotic stroke mice. Conclusions Treadmill exercise improved motor function and short-term memory through increasing synaptic plasticity and neurogenesis in photothrombotic stroke mice. Treadmill exercise can be used as an effective treatment strategy to improve brain function related to stroke.

PURPOSE: Goserelin is a drug used for chemical castration. In a rat model, we investigated whether surgical and chemical castration affected memory ability through the protein kinase A (PKA)/cyclic adenosine monophosphate response element-binding protein (CREB)/brain-derived neurotrophic factor (BDNF) and c-Raf/mitogen-activated protein kinases-extracellular signal–regulated kinases (MEK)/extracellular signal–regulated kinases (ERK) pathways in the hippocampus. METHODS: Orchiectomy was performed for surgical castration and goserelin acetate was subcutaneously transplanted into the anterior abdominal wall for chemical castration. Immunohistochemistry was done to quantify neurogenesis. To assess the involvement of the PKA/CREB/BDNF and c-Raf/MEK/ERK pathways in the memory process, western blots were used. RESULTS: The orchiectomy group and the goserelin group showed less neurogenesis and impaired short-term and spatial memory. Phosphorylation of PKA/CREB/BDNF and phosphorylation of c-Raf/MEK/ERK decreased in the orchiectomy and goserelin groups. CONCLUSIONS: Short-term memory and spatial memory were affected by surgical and chemical castration via the PKA/CREB/BDNF and c-Raf/MEK/ERK signaling pathways.
Abdominal Wall ; Adenosine Monophosphate ; Blotting, Western ; Castration ; Cyclic AMP-Dependent Protein Kinases ; Down-Regulation ; Goserelin ; Hippocampus ; Immunohistochemistry ; Memory ; Memory, Short-Term ; Models, Animal ; Neurogenesis ; Orchiectomy ; Phosphorylation ; Phosphotransferases ; Spatial Memory