Korean Cities Research Articles

Quantifying urban sprawl and investigating the cause-effect links among urban sprawl factors, commuting modes, and time: A case study of South Korean cities

This study aims to create a detailed urban sprawl index, investigate the relationship between density and other urban sprawl factors, and analyze how these factors affect commuting mode time in South Korean cities using structural equation modeling and multiple linear regression. Urban sprawl factors are categorized from various individual perspectives into density, urban landscape, land-use mix, centeredness, and street connectivity. We show that while scores for urban landscape, density, and centeredness were high in cities with large populations, scores for land-use mix and street connectivity were high in cities with medium and small populations. We found that density had significant effects on urban landscape, centeredness, and street connectivity. The indirect effects of density on commuting modes and time counterbalance the direct effects, indicating that while the indirect effects do not change the direction of the direct effects, they reduce their magnitude, making the total effect smaller than the direct effect. A higher density was associated with fewer commuters using cars and higher numbers of public transit, but the reduction in cars was limited to less than 30 min of commuting time. In addition, high density was positively associated with commuting time. High scores for urban landscape, land-use mix, and street connectivity were associated with a reduction in commuting time but did not have an effect on the conversion from cars to public transit for the journey to work. High scores for urban landscape and street connectivity were associated with more walking commuters but were limited to commuting for less than 60 min. This study shows that urban sprawl factors are mutually complementary for commuting mode changes and time. This study provides evidence for establishing sustainable transportation plans. In addition, the urban sprawl index can be used in future research to investigate the effects of urban sprawl on various social and environmental phenomena.

Compound impact of heatwaves on vulnerable groups considering age, income, and disability

The increasing frequency and intensity of heat waves due to climate change and urbanization have caused serious public health problems, especially in urban areas in which the heat effects are amplified by dense infrastructure and limited green space. This study examined the impact of heatwaves on vulnerable populations in Korean cities, focusing on how age, income, and disability are associated with higher health risks. In our study, we analyzed healthcare big data from 2010 to 2022 for seven major Korean cities. We employed a distributed lag non-linear model to assess the relationship between heat exposure and health outcomes, allowing us to quantify the compounded vulnerabilities due to socioeconomic and physical factors. The results showed that the association of compounded vulnerability was more pronounced in patients hospitalized through the emergency room, a severe health outcome, than in patients with mild health outcome such as outpatient visits for heat-related illnesses. The association of compounded vulnerability was particularly evident in the elderly population. These findings suggest the need for tailored heatwave preparedness strategies for vulnerable groups, contributing to the broader discourse on climate adaptation and public health resilience.

B-063 Changes in nonalcoholic fatty liver disease and M2BPGi due to lifestyle intervention in primary healthcare

Abstract Background A healthy lifestyle is the most important method for managing nonalcoholic fatty liver disease (NAFLD). Mac-2-binding protein glycosylated isomer (M2BPGi) has been suggested as a biomarker for NAFLD. This study aimed to determine the efficacy of personalized lifestyle interventions on NAFLD remission. Methods This single-arm intervention study recruited participants with NAFLD who underwent health checkups at seven health-promotion centers in five South Korean cities. Fatty liver diagnosis was based on ultrasonography (US). The 109 individuals were recruited for personalized lifestyle interventions of hypocaloric diets and exercise. The participants attended the lifestyle intervention programs once per month for the first 3 months, and once every 3 months for the subsequent 6 months. And phone-based self-monitoring were also provided monthly during the 3-month follow-up period. The primary outcome was NAFLD remission at month 12 as measured on US and magnetic resonance elastography. The secondary outcomes were the changes in metabolic factors and M2BPGi. Results The 108 individuals (62 males and 46 females; age 51.1±12.4 years, mean±standard deviation) were finally analyzed after the 12month intervention. Body mass index, waist circumference (WC), blood pressure, blood lipids (total cholesterol, triglycerides, and HDL-C), and fasting blood sugar levels were improved relative to baseline (all P<0.05). Fatty liver at or above the moderate grade according to US was decreased at month 12 relative to baseline (67.6% vs 50.9%) (P=0.002). M2BPGi levels decreased during the 12-month study period (P<0.001). M2BPGi levels were moderately correlated with hepatic fat fraction by magnetic resonance imaging (r=0.33, P=0.05). WC (OR=0.82, 95% CI=0.67-1.00, P=0.05) and HDL-C (OR=1.17, 95% CI=1.03-1.32, P=0.014) were associated with remission of fatty liver in the multivariate analysis. Conclusions The personalized lifestyle intervention was effective in improving fatty liver and metabolic factors, but not hepatic stiffness, in NAFLD.

Association of fluoride exposure with disease burden and neurodevelopment outcomes in children in South Korea.

Community water fluoridation is an effective public health strategy for preventing dental caries, yet. Concerns exist about potential health problems. This study explores associations between tap water fluoride levels and pediatric disease burden, as well as neurodevelopmental outcomes at 6years of age. This nationwide population-based cohort study included children born in Korean cities with and without tap water fluoridation projects, between 2006 and 2012, aiming for a fluoride concentration of 0.8 ± 0.2mg/L in treated tap water. Data from the National Health Insurance Service were used, spanning from birth to 2018. The relationship between exposure to fluoridated tap water and incidence of 16 childhood diseases that were previously identified as potentially linked to fluoride exposure were examined. Additionally, we evaluated the neurodevelopmental outcomes across various domains, including gross motor, fine motor, cognition, language, social skills, and self-help functions. These assessments were performed using data from a comprehensive national health screening program for children aged six years. A fluoride-unexposed group included 22,881 children, whereas a fluoride-exposed group comprised 29,991 children (52% males). Children in the fluoride-exposed group had a decreased risk of dental caries and bone fractures [hazard ratio (95% confidence interval, CI), 0.76 (0.63-0.93) and 0.89 (0.82-0.93), respectively] and increased risk of hepatic failures [1.85, (1.14-2.98)] compared to those in the unexposed group. Additionally, the risk ratio of abnormal neurodevelopmental screening outcomes increased by 9%, but this was statistically uncertain (95% CI, 0.95-1.26). Fluoridated tap water was associated with an increased risk of hepatic failure but a decreased risk of bone fractures in children. The association between fluoridated tap water and neurodevelopmental screening outcomes at 6years remains unclear, highlighting the need for further studies to clarify this association.

Integrated wind farm solutions: Harnessing clean energy for electricity, hydrogen, and freshwater production

This research explores the design, modeling, and feasibility of a multi-energy wind power plant in South Korea, aimed at producing electricity, fresh water, hydrogen, and oxygen. The main goal of the current study is to help the energy production system that uses the high potential of wind energy in areas with wind potential to increase power and efficiency and reduce harmful environmental effects for the production of hydrogen and fresh water. The system employs a PEM electrolyzer unit and reverses osmosis technology for hydrogen, oxygen, and freshwater generation. The innovation of this study lies in the integration of wind farm design with optimal electricity allocation to electrolyzers, reverse osmosis units, and the grid, maximizing efficiency and sustainability. A comprehensive case study is presented, evaluating the viability of putting the suggested strategy into practice in ten South Korean cities, with a focus on hydrogen production from wind energy. The study investigates ten scenarios for selecting the number of wind turbines, electrolyzers, and reverse osmosis devices, and sixteen scenarios for dividing wind farm coefficients to supply grid electricity, electrolyzer electricity, and reverse osmosis electricity. The optimal result indicates that 5% of wind farm electricity should be allocated to reverse osmosis units, 15% to electrolyzers, and 80% to the grid. The economic analysis indicates that among the system components, the wind farm, reverse osmosis, and PEM electrolyzer represent the highest costs. The system's performance is assessed across ten cities in South Korea, with Yeosu, Incheon, and Busan determined to be the best sites for the proposed power plant because of their strong potential to produce hydrogen using wind energy. Implementing the system in Yeosu, the optimal city, may stop 9664.326 tons of carbon dioxide from being released, generate 47374.15 MWh of electricity, and expand 46 ha of green space. Additionally, selling 9474.83 MW of electricity to the grid would meet the annual electricity needs of 929 people in Yeosu, South Korea. This study emphasizes the potential of wind power plants in South Korea to contribute to sustainable energy production and carbon dioxide reduction, highlighting their potential for a greener and more sustainable future.

Relationship between hospital ethical climate, critical thinking disposition, and nursing task performance

BackgroundAs ethical conflicts increase in the ever-changing healthcare field, nursing task performance, which is the overall ability of a nurse’s professional knowledge, attitude, and skills, is important for patient health and safety, the provision of quality nursing care, and the appropriate resolution of nursing ethical problems. This study aimed to evaluate the mediating effect of critical thinking disposition on the relationship between hospital ethical climate and nursing task performance.MethodsA cross-sectional study was conducted. A total of a convenience sample of 200 clinical nurses from two Korean cities were recruited between November and December 2021. Direct questionnaires and online surveys were used to collect the data. The study variables were analyzed using descriptive statistics, correlations, and a model tested using the Hayes PROCESS macro (Model 4) mediation model.ResultsThe mean scores for hospital ethical climate, critical thinking disposition, and nursing task performance were 91.86 ± 11.29, 97.74 ± 10.70, and 138.58 ± 14.95, respectively. Hospital ethical climate and critical thinking disposition were positively correlated with nursing task performance. In the mediation test model, hospital ethical climate was found to be positively and significantly associated with nursing task performance (ß = 0.46, p < .001) with the mediation of critical thinking disposition (ß = 0.70, p < .001).ConclusionsHospital ethical climate and critical thinking disposition may be important determinants of task performance among clinical nurses. Hospital administrators should make efforts to create a more positive ethical climate in hospitals and conduct education and campaigns on a positive hospital ethical climate for hospital staff to improve nurses’ performance.

Assessing the impact of urbanization on forest carbon stocks and social costs using a machine learning approach

Urbanization frequently precipitates urban sprawl, resulting in deforestation and alterations in landscape and land alterations. Such transformations profoundly impact the carbon stocks within metropolitan regions. This study examines the ramifications of urbanization on alterations in carbon stocks within urban forests across ten South Korean cities experiencing substantial urbanization over the past 15 years. Leveraging machine learning techniques and high-resolution satellite imagery, we scrutinize changes in land usage and urban forests, utilizing them to gauge the societal costs linked with shifts in urban carbon stocks. Furthermore, we integrate regional-level data sourced from national forests to enhance the precision of carbon stock estimations. Data analysis reveals that over the 15 years, urban areas expanded at an average rate of 4.43 km2 annually. In comparison, forested areas decreased by an average of −2.19 km2 per year, resulting in an average annual decline of −3171 tC in forest carbon stocks due to urbanization. The fluctuation in carbon stocks across the urban forests of the ten cities ranged from −68 % to 48 % over 15 years, primarily influenced by the extent of preserved forest area, with forest composition playing a secondary role. Concurrently, carbon sequestration efficiency varied between cities, ranging from 8 % to 57 % over 15 years, contingent upon tree type and forest age composition. An approximate loss of 174,380 tCO2eq of carbon stocks attributable to urbanization is estimated, with the associated social cost of increased emissions estimated at $8,893,396. Effective management of carbon emissions and sinks within urban locales is paramount for climate change mitigation, given the substantial contribution of urban areas to global carbon emissions. This study underscores the significance of urban forest management in carbon governance and furnishes valuable insights into nations undergoing rapid urban expansion.

Diagnosing communities’ childcare friendliness: case studies of two South Korean cities

ABSTRACT As the low birth rate in Korea is a pressing issue, enhancing children’s quality of life and creating a favorable childcare environment have become crucial national priorities. This study defines the concepts of childcare friendliness and a childcare-friendly community and develops a mixed-method framework to diagnose communities’ childcare friendliness. Specifically, it integrates neighborhood-level quantitative measures of the supply levels and physical accessibility of childcare-related infrastructure, along with a qualitative survey of residents’ needs and participatory workshops on their ideal childcare-friendly communities. The diagnostic framework of the study was applied to two distinctive urban-rural consolidated cities, Namyangju, including new cities, and Gongju, dominant in rural areas. The results show intercity and intracity spatial disparities in the current status and desired future of childcare-friendly communities in both cities. The concept, methodological framework, and results of this study can help local governments and communities identify unique issues with neighborhood childcare and formulate locally tailored policies and urban/regional plans towards a society conducive to child rearing and development.

Developing a flood risk assessment model with genetic algorithm-based weights

To reduce flood risk efficiently within constrained disaster prevention budgets, governments employ economic analyses and qualitative flood risk assessments. However, conventional methods, such as entropy weight and the Analytic Hierarchy Process method, have limitations in terms of the accuracy of the flood risk index. Here, we overcome these limitations by applying a genetic algorithm (GA) – an optimization method mimicking a natural selection process and biological genetic evolution. We developed a new flood risk index by using GA to calculate weights to indicators associated with four items (Hazard, Exposure, Vulnerability, and Capacity) for 161 Korean cities and counties from 2016 to 2021. The indicators (number of buildings, farmland area, dependent population, etc.) for the Exposure and Vulnerability items were reflected in the evaluation only for damaged targets directly exposed to flood risk, using grid cells of indicators overlaid on the flood risk map. Our GA-based method aimed to optimize each indicator’s weights to minimize errors between damage rankings and flood risk index rankings. Results show that our method reduced errors by 21.42 % during 2016–2021, outperforming traditional methods. Therefore, it is easy to identify municipalities that lack disaster prevention capabilities and are vulnerable to flood risk by comparing flood risk indices under the same conditions, such as maximum rainfall index. Our proposed method could better aid local government in decision-making for flood risk mitigation by allocating constrained budgets efficiently.

The hasukjip: situation in 2020s. in the Republic of Korea and abroad

Abstract. The hasukjip (하숙집) is a form of small business in the South Korean cities. It consists of a house with a number (small hasukjip has near 10-20 rooms, but big- some dozens rooms or more) boarding rooms. Before Coronavirus situation any Korean and foreign students living in hasukjips and Koreans understood hasukjips only as a type of private dormitory, but if we examine the example of changes in hasukjips we can also consider trends in the Korean society. Although hasukjips reflect elements and aspects of the various sides of the life in Korea, Korean and foreign scholars have not undertaken research on the situation of the hasukjip or changes in its history and this institution remains little-unknown in the Western academic world. This work based on the sociological materials (these interviews had place in 2022. In this sociological interview for persons, who lived in the hasukjips, took part 184 Korean people and 20 foreigners. Moreover, was created interview for masters of the hasukjip. In this event took part 50 persons. Lists of the interview and further information were added as attachments) and some written works. The aim of this article is to consider modern situation of the hasukjip in Korea and abroad, its place in life of the Korean people.

Comparative analysis of the economic effects of special economic zones in China and Korea: evidence from a PSM difference-in-difference method

ABSTRACT This paper examines the economic effects of the establishment of Special Economic Zones (SEZs) on the export of industrial complexes in China and Korea, focusing on the synergistic economic effects between different types of SEZs, using the Propensity Score Matching difference-in-difference method. We use panel data of 284 Chinese cities and 162 Korean cities between 2000 and 2019, focusing on 93 industrial complexes in China, and 569 industrial complexes in Korea. We compare the effects of Free Trade Zones (FTZs) with other special economic zones, including Bonded Areas (BA) in China and Free Economic Zones (FEZ) and Foreign Investment Regions (FIZ) in Korea. The establishment of SEZs has a significant positive impact on the export growth of industrial complexes in both China and Korea. In Korea, a significant synergy effect on export is found between the FTZ and the FIZs. There is no synergy effect found between FEZs and other economic zones. After the implementation of the FTZ policy in China, the export of BA’s industrial complexes with ports and airports significantly increased, indicating that the FTZs have a positive synergy effect on the BAs with convenient transportation.

Examining the experiences of mid-career nurses in hospitals: a phenomenological study

Background The turnover of new and mid-career nurses has been increasing, leading to challenges in recruiting and retaining nursing staff. Objectives Securing and retaining mid-career nurses is crucial for ensuring high-quality care. However, little is known about mid-career nurses’ experiences regarding turnover. This study aimed to understand the experiences of mid-career nurses and identify strategies to enable mid-career nurses to maintain long-term employment in health services. Design Colaizzi’s phenomenological methodology was adopted to illuminate the subjective meaning derived from the work-related challenges of mid-career nurses, leading to turnover. Focus group interviews were conducted to delve into the work challenges faced by mid-career nurses. Method The participants were 23 mid-career nurses working in one tertiary hospital and six secondary hospitals across three Korean cities, recruited using purposive and snowball sampling. The inclusion criteria entailed a minimum of three years of nursing experience and current employment within a designated department or clinical area within the hospital environment, commonly known as a nursing unit. Such units encompassed a range of clinical settings, including medical-surgical units, intensive care units, and emergency rooms. The interview data were transcribed verbatim, and significant statements were extracted from abstract sentences to derive themes through an analytical process. Results Analysis of the work experiences of 23 mid-career nurses in medical institutions yielded 15 themes and 4 theme clusters derived from 353 meaningful statements. These theme collections were identified as ‘Difficulties endured as a mid-career nurse’, ‘Meaningless and regrettable new graduate nurses’ education’, ‘An inexpressibly poor work environment’, and ‘Systems and policies needed to remain in the hospital’. Conclusions Difficulties faced by mid-career nurses including the establishment of an education and career development system, provisions for guaranteed leave, a diverse and flexible work system, opportunities for effective communication, and engagement with the opinions of mid-career nurses should promptly be addressed.

Can food self-reliance support urban sustainability? The lessons from urban gardening in North Korea

Although sustainable urban development has been conceptualized in a vast array of proposals, it seems that the prioritization of economic development over environmental and social concerns limits real progress in making cities more sustainable. This paper studies whether an orientation towards self-reliance can contribute in some way to urban sustainability through examining the case of gardening in North Korean cities. The results demonstrate that even though self-reliance has long been a part of the national ideology, only its practice at the household level has resulted in significant improvements in urban sustainability. The key therein lies in family ties, the responsibility to which oblige people to actively practice a more conscious consumer behavior. Meanwhile, the economic empowerment of women, who sell a part of the harvest from their urban gardens at the local market, has not precipitated their broader involvement in either social or political activities.

Disaster Resilience of Korean Cities Using Data Envelopment Analysis

Disaster Resilience of Korean Cities Using Data Envelopment Analysis

Retrospective Study of the Prevalence and Associated Factors of Gallbladder Polyps among Residents of Two Korean Cities.

Background/Aims: Well-known risk factors for gallbladder polyps include metabolic syndrome, age, and dyslipidemia. Jeju Island is approximately 80 km from the Korean peninsula and is divided into two administrative regions (Jeju City and Seogwipo City), with Mount Halla intervening in the center. Jeju City has higher employment and birth rates than Seogwipo City. Age and alcohol consumption differ between the two regions, and these factors may affect the prevalence of gallbladder polyps (GBPs). Therefore, we investigated the prevalence of GBPs and compared various factors, including alcohol consumption habits and age, associated with GBPs among residents in the two regions. Methods: This study included 21,734 residents who visited the Health Screening and Promotion Center of Jeju National University Hospital between January 2009 and December 2019. We investigated the prevalence and associated factors of GBPs among residents of Jeju City and Seogwipo City. Results: The prevalence of GBPs in Jeju City and Seogwipo City was 9.8% and 8.9% (p = 0.043), respectively. The mean age and rate of high-risk alcohol intake were higher in Seogwipo City. The mean body mass index and levels of fasting blood glucose, total cholesterol, low-density lipoprotein cholesterol, aspartate aminotransferase, gamma-glutamyl transferase, and alkaline phosphatase were lower in Jeju City. Conclusions: This study demonstrated a significant difference in GBP prevalence between the two regions of Jeju Island. Age and alcohol consumption might contribute to this difference; however, further prospective cohort studies are warranted to confirm our findings.

Mortality Burden Due to Short-term Exposure to Fine Particulate Matter in Korea.

Excess mortality associated with long-term exposure to fine particulate matter (PM2.5) has been documented. However, research on the disease burden following short-term exposure is scarce. We investigated the cause-specific mortality burden of short-term exposure to PM2.5 by considering the potential non-linear concentration-response relationship in Korea. Daily cause-specific mortality rates and PM2.5 exposure levels from 2010 to 2019 were collected for 8 Korean cities and 9 provinces. A generalized additive mixed model was employed to estimate the non-linear relationship between PM2.5 exposure and cause-specific mortality levels. We assumed no detrimental health effects of PM2.5 concentrations below 15 μg/m3. Overall deaths attributable to short-term PM2.5 exposure were estimated by summing the daily numbers of excess deaths associated with ambient PM2.5 exposure. Of the 2 749 704 recorded deaths, 2 453 686 (89.2%) were non-accidental, 591 267 (21.5%) were cardiovascular, and 141 066 (5.1%) were respiratory in nature. A non-linear relationship was observed between all-cause mortality and exposure to PM2.5 at lag0, whereas linear associations were evident for cause-specific mortalities. Overall, 10 814 all-cause, 7855 non-accidental, 1642 cardiovascular, and 708 respiratory deaths were attributed to short-term exposure to PM2.5. The estimated number of all-cause excess deaths due to short-term PM2.5 exposure in 2019 was 1039 (95% confidence interval, 604 to 1472). Our findings indicate an association between short-term PM2.5 exposure and various mortality rates (all-cause, non-accidental, cardiovascular, and respiratory) in Korea over the period from 2010 to 2019. Consequently, action plans should be developed to reduce deaths attributable to short-term exposure to PM2.5.

Paradoxical choice of Korean consumers: categorization effect, health halo and averaging bias

PurposeThis research aims to elucidate why consumers decide to eat meals that seem to be higher in calories and salt, despite their goal being to consume fewer calories and sodium. Korean participants are to be used for this study. The present research further investigated the impacts of categorization and averaging bias in relation to the health halo phenomenon, specifically focusing on traditional food and textured vegetable protein (soy meat) burgers. Thus, the present research investigated how consumers' intentions contrasted with their consumption goals in food choice circumstances.Design/methodology/approachWe partitioned the survey due to the COVID-19 epidemic. A single, well trained surveyor first surveyed customers at cafés in Seoul and six other Korean cities. We received 102 in-person survey replies. A total of 254 advanced degree or undergraduate students from two universities completed an online questionnaire. There are 356 responses. Two studies were conducted where participants were instructed to evaluate the perceived healthiness, calorie content, and sodium level of different food items. The specifics of each study are elucidated in the main body of the paper.FindingsThis study shows that Koreans categorize meals as virtue or vice depending on their perceived healthiness, validating the categorization effect. Furthermore, this research demonstrated that consumers' perceptions of the health benefits of traditional meals and soy meat burgers impact their categorization. Koreans also assessed the average of the vice and virtue and found vice-virtue combination meals healthier than the vice alone. This affects how calories and sodium are perceived. This study also shown that high virtue affects averaging bias more than weak virtue in meals with vice and virtue combo.Originality/valueThis study extended food categorization and averaging bias to non-US consumers and confirmed this contradictory meal choice is universal. Health halo also affects food health perception. The results of this study revealed that Koreans consider traditional food healthier than western junk food. Korean customers incorrectly assume soy meat burgers have fewer calories and sodium than regular burgers. Thus, this study explains Korean consumers' food health misconceptions related to paradoxical consumption.

Analysis of Competitiveness in the Domestic Semiconductor Cluster Using Entropy Technique: Based on the GEM-ESG Model

Purpose - The study aims to conduct an empirical analysis of semiconductor cluster integrated competitiveness with a focus on the GEM-ESG model. Specifically, the study seeks to compare and analyze the development factors of semiconductor clusters in different regions. The results of the empirical study will reveal a clear concentration phenomenon in the semiconductor industry clusters of some regions.&#x0D; Design/Methodology/Approach - Previous research has established the factors influencing the competitive advantage of industrial clusters. The study collected competitive indicators from major South Korean cities and regions, incorporating these into the GEM model, and exploring ESG indicators relevant to the semiconductor industry. The study utilized Entropy Technique analysis to empirically assess the competitiveness of the South Korean semiconductor cluster and conduct comparative testing of the research findings.&#x0D; Findings - The results revealed a concentration phenomenon in the semiconductor industry clusters of Yongin and Chungbuk Province. Additionally, the study highlighted the importance of factors such as “groundings (G)”, “enterprise management (E)”, “market conditions (M)”, and ESG practices in determining competitiveness.&#x0D; Research Implications - Through empirical analyses, the study emphasizes the significance of GEM and ESG factors in the analysis of industrial clusters, particularly in contributing to long-term sustainability and competitive advantage focusing on the collaboration and alignment of ESG values.

Changes in nonalcoholic fatty liver disease and M2BPGi due to lifestyle intervention in primary healthcare.

A healthy lifestyle is the most important method for managing nonalcoholic fatty liver disease (NAFLD). Mac-2-binding protein glycosylated isomer (M2BPGi) has been suggested as a biomarker for NAFLD. This study aimed to determine the efficacy of personalized lifestyle interventions on NAFLD remission. This single-arm intervention study recruited participants with NAFLD who underwent health checkups at seven health-promotion centers in five South Korean cities. Fatty liver diagnosis was based on ultrasonography (US). The 109 individuals were recruited for personalized lifestyle interventions of hypocaloric diets and exercise. The participants attended the lifestyle intervention programs once per month for the first 3 months, and once every 3 months for the subsequent 6 months. In addition to sessions through center visits, phone-based intervention and self-monitoring at 4-, 5-, 7-, and 8-month were provided during the 9-month intervention period. And phone-based self-monitoring were also provided monthly during the 3-month follow-up period. The primary outcome was NAFLD remission at month 12 as measured on US and magnetic resonance elastography. The secondary outcomes were the changes in metabolic factors and M2BPGi. The 108 individuals (62 males and 46 females; age 51.1±12.4 years, mean±standard deviation) were finally analyzed after the 12month intervention. Body mass index, waist circumference (WC), blood pressure, blood lipids (total cholesterol, triglycerides, and HDL-C), and fasting blood sugar levels were improved relative to baseline (all P<0.05). Fatty liver at or above the moderate grade according to US was decreased at month 12 relative to baseline (67.6% vs 50.9%) (P = 0.002). M2BPGi levels decreased during the 12-month study period (P<0.001). M2BPGi levels were moderately correlated with hepatic fat fraction by magnetic resonance imaging (r = 0.33, P = 0.05). WC (OR = 0.82, 95% CI = 0.67-1.00, P = 0.05) and HDL-C (OR = 1.17, 95% CI = 1.03-1.32, P = 0.014) were associated with remission of fatty liver in the multivariate analysis. The personalized lifestyle intervention was effective in improving fatty liver and metabolic factors, but not hepatic stiffness, in NAFLD. ICTRP, cris.nih.go.kr (KCT0006380).

Vitamin D Status and Reference Intervals Measured by Liquid Chromatography-Tandem Mass Spectrometry for the Early Adulthood to Geriatric Ages in a South Korean Population during 2017-2022.

This study aimed to describe the latest 25-hydroxyvitamin D (25(OH)D) status of the South Korean population aged ≥ 20 years using 25(OH)D concentrations measured by liquid chromatography-tandem mass spectrometry and to determine the factors associated with total 25(OH)D concentrations. This cross-sectional, retrospective study consecutively selected 119,335 subjects with a median age of 57 (20-101) years who underwent health checkups among 13 Korean cities during 2017-2022. The total 25(OH)D concentration was 54.5 ± 24.0 nmol/L (mean ± SD). The 7.6%, 47.5%, and 82.9% of participants had 25(OH)D less than 25, 50, and 75 nmol/L, respectively. The prevalence of 25(OH)D deficiency (<25 nmol/L) was higher in females than in males (8.9% vs. 6.1%) and varied between age groups, decreasing in older subjects. Those aged 20-29 years had the highest prevalence of 25(OH)D deficiency (23.0% in females and 20.1% in males), which also varied between cities. In the adjusted model, female sex, older age, summer and autumn seasons, lower body mass index (<25 kg/m2), and lower high-sensitivity C-reactive protein concentration (<1 mg/L) were associated with higher total 25(OH)D concentrations. This study could provide an exact understanding of the status of vitamin D and help devise strategies to prevent vitamin D deficiency among the Korean population.