Reported Adverse Events and Associated Factors in Korean Coronavirus Disease 2019 Vaccinations.

BACKGROUND: Despite their effectiveness, coronavirus disease 2019 (COVID-19) vaccines have been associated with adverse effects, underscoring the importance of continuous surveillance to ensure vaccine safety and effective management of public health. Herein, the characteristics and risk factors of vaccine-related adverse events (AEs) were identified to gain an in-depth understanding of vaccine safety by investigating the impact of the vaccination dose on changes in post-vaccination AEs. METHODS: Herein, a linked database of COVID-19 vaccination records from the Korea Disease Control and Prevention Agency, AE reports from the COVID-19 Vaccination Management System, and healthcare claims from the National Health Insurance Service, targeting ≥ 5-year-old individuals, was utilized (study duration = February 26, 2021, to January 31, 2023). The frequency and severity of reported post-vaccination AEs were evaluated. Furthermore, we specifically explored AEs in relation to the cumulative dosage of vaccines administered while evaluating associated risk factors. RESULTS: During the observation period, 42,804,523 individuals completed the COVID-19 vaccination series, with 365,900 reporting AEs, with headache, muscle pain, and fever being the most frequently reported. Notably, the AE reports were approximately twice as high for women than for men, which was further exacerbated following both doses. Analysis by age group revealed that AE reports were lower among children, adolescents, and older adults than in the middle-aged cohort (age = 50-64 years), with higher reports observed for 18-49-year-old individuals. Additionally, a higher risk of reporting was identified among individuals with lower socioeconomic status compared with those of middle socioeconomic status. Excluding dementia, the risk of reporting AEs was high in individuals with underlying diseases compared with those without, for instance, the risk of reporting AEs following two-dose vaccinations was approximately twice as high in individuals with chronic obstructive pulmonary disease and asthma. CONCLUSION: These findings indicate that women, younger people, those with a lower socioeconomic status, and those with underlying health conditions reported a higher incidence of AEs following COVID-19 vaccinations. This emphasizes the need for continued monitoring to ensure safe vaccination and address vaccine-related anxiety and fear, especially within the aforementioned groups.

A Causality Assessment Framework for COVID-19 Vaccines and Adverse Events at the COVID-19 Vaccine Safety Research Center.

During the coronavirus disease 2019 (COVID-19) pandemic, conclusively evaluating possible associations between COVID-19 vaccines and potential adverse events was of critical importance. The National Academy of Medicine of Korea established the COVID-19 Vaccine Safety Research Center (CoVaSC) with support from the Korea Disease Control and Prevention Agency to investigate the scientific relationship between COVID-19 vaccines and suspected adverse events. Although determining whether the COVID-19 vaccine was responsible for any suspected adverse event necessitated a systematic approach, traditional causal inference theories, such as Hill's criteria, encountered certain limitations and criticisms. To facilitate a systematic and evidence-based evaluation, the United States Institute of Medicine, at the request of the Centers for Disease Control and Prevention, offered a detailed causality assessment framework in 2012, which was updated in the recent report by the National Academies of Sciences, Engineering, and Medicine (NASEM) in 2024. This framework, based on a weight-of-evidence approach, allows the independent evaluation of both epidemiological and mechanistic evidence, culminating in a comprehensive conclusion about causality. Epidemiological evidence derived from population studies is categorized into four levels-high, moderate, limited, or insufficient-while mechanistic evidence, primarily from biological and clinical studies in animals and individuals, is classified as strong, intermediate, weak, or lacking. The committee then synthesizes these two types of evidence to draw a conclusion about the causal relationship, which can be described as "convincingly supports" ("evidence established" in the 2024 NASEM report), "favors acceptance," "favors rejection," or "inadequate to accept or reject." The CoVaSC has established an independent committee to conduct causality assessments using the weight-of-evidence framework, specifically for evaluating the causality of adverse events associated with COVID-19 vaccines. The aim of this study is to provide an overview of the weight-of-evidence framework and to detail the considerations involved in its practical application in the CoVaSC.

The Combined Effects of Alcohol Consumption and Smoking on Cancer Risk by Exposure Level: A Systematic Review and Meta-Analysis.

BACKGROUND: Alcohol consumption is a major risk factor for cancer, and when combined with smoking, the risk increases. Nevertheless, few studies have comprehensively evaluated the combined effects of alcohol consumption and smoking on the risk of various cancer types. Therefore, to assess these effects, we conducted a systematic review and meta-analysis. METHODS: We performed a systematic search of five literature databases, focusing on cohort and case-control studies. Considering exposure levels, we quantified the combined effects of alcohol consumption and smoking on cancer risk and assessed multiplicative interaction effects. RESULTS: Of 4,452 studies identified, 24 (4 cohort studies and 20 case-control studies) were included in the meta-analysis. We detected interaction effect of light alcohol and moderate smoking on head and neck cancer risk (relative risk [RR], 4.26; 95% confidence interval [CI], 2.50-7.26; I² = 65%). A synergistic interaction was observed in heavy alcohol and heavy smoking group (RR, 35.24; 95% CI, 23.17-53.58; I² = 69%). In more detailed cancer types, the interaction effect of heavy alcohol and heavy smoking was noticeable on oral (RR, 36.42; 95% CI, 24.62-53.87; I² = 46%) and laryngeal (RR, 38.75; 95% CI, 19.25-78.01; I² = 69%) cancer risk. CONCLUSION: Our study provided a comprehensive summary of the combined effects of alcohol consumption and smoking on cancers. As their consumption increased, the synergy effect became more pronounced, and the synergy effect was evident especially for head and neck cancer. These findings provide additional evidence for the combined effect of alcohol and smoking in alcohol guidelines for cancer prevention.

Development and psychometric testing of a questionnaire for the Korea Youth risk behavior survey to assess physical activity behaviors.

BACKGROUND: Physical activity is essential for physical, mental, and cognitive health. Providing evidence to develop better public health policies to encourage increased physical activity is crucial. Therefore, we developed an in-depth survey as part of the Korea Youth Risk Behavior Survey to assess the current status and determinants of physical activity among Korean adolescents. METHODS: We developed an initial version of the questionnaire based on a review of validated questionnaires, recent trends and emerging issues related to adolescent physical activity, and the national public health agenda pertaining to health promotion. Content validity was confirmed by a panel of 10 experts. Face validity was confirmed through focus group interviews with 12 first-year middle school students. The test-retest reliability of the questionnaire was evaluated by administering it twice, approximately two weeks apart, to a sample of 360 middle and high school students. Additionally, the frequency or average number of responses was analyzed in a sample of 600 students who participated in the initial test-retest reliability evaluation of the questionnaire developed in this study. RESULTS: Through item pool generation and content and face validity test, the final 15 questionnaire items were developed across five themes: levels of physical activity, school sports club activities, transportation-related physical activity, physical activity-promoting environments, and factors mediating physical activity. The test-retest reliability ranged from fair to substantial. Results from the newly developed survey reveal that only a minority of adolescents engage in sufficient physical activity, with only 17.2% and 21.5% participating in vigorous and moderate-intensity activities, respectively, for at least five days per week. Among school-based activities, 44.3% of students do not participate in school sports clubs due to reasons including absence of clubs and disinterest in exercise. The major motivators for physical activity are personal enjoyment and health benefits, whereas preferences for other leisure activities and academic pressures are the predominant barriers. CONCLUSIONS: This study developed valid and reliable in-depth survey items to assess physical activity among Korean youths. It will hopefully enhance our understanding of adolescent physical activity, offering essential preliminary evidence to inform the development of public health strategies aimed at promoting adolescent health.

Cost-benefit analysis of human adenovirus vaccine development in a Korean military setting.

BACKGROUND: Human adenovirus (HAdV) is a prevalent causative agent of acute respiratory disease (ARD) and is frequently responsible for outbreaks, particularly in military environments. Current vaccines do not effectively cover HAdV subtypes commonly found among Korean military personnel, highlighting the need for a new targeted vaccine. This study presents a cost-benefit analysis to evaluate the economic viability of developing and implementing such a vaccine within a military context. METHODS: We adopted a societal perspective for this cost-benefit analysis, which included estimating costs associated with vaccine development, production, and distribution over a projected timeline. We assumed a development period of five years, after which vaccine production and administration were initiated in the sixth year. The cost associated with vaccine development, production, and dispensation was considered. The benefits were calculated based on both direct and indirect cost savings from preventing HAdV infections through vaccination. All financial figures were expressed in 2023 US dollars. A sensitivity analysis was conducted to explore the impact of varying factors such as vaccination rate, incidence of infection, vaccine efficacy, and discount rate. RESULTS: For the base case scenario, we assumed a vaccination rate of 100 %, an incidence rate of 0.02, and a vaccine efficacy of 95 %, applying a 3 % discount rate. Initially, in the sixth year, the benefit-cost ratio stood at 0.71, suggesting a cost disadvantage at the onset of vaccination. However, this ratio improved to 1.32 in the following years, indicating a cost benefit from the seventh year onward. The cumulative benefit-cost ratio over a decade reached 2.72. The outcomes from the sensitivity analysis were consistent with these findings. CONCLUSION: Our cost-benefit analysis demonstrates that the introduction of an HAdV vaccine for the Korean military is economically advantageous, with substantial cost benefits accruing from the seventh year after the commencement of vaccination.

Handgrip strength thresholds associated with metabolic syndrome risk in children and adolescents: a systematic review and meta-analysis.

OBJECTIVES: Certain studies have reported that handgrip strength (HGS) is associated with metabolic health risks in children and adolescents, and some studies have suggested HGS thresholds for identifying poor metabolic health. Therefore, we aimed to determine the HGS thresholds associated with metabolic syndrome (MetS) in children and adolescents through a systematic review. METHODS: We searched 3 electronic databases from their inception until October 2023 to identify original papers that focused on children and adolescents and assessed their risks of MetS according to specific HGS values. Studies were selected for inclusion through a planned screening process based on specific criteria. The Quality Assessment Tool for Diagnostic Accuracy Studies version 2 (QUADAS-2) was used to evaluate quality, and a meta-analysis was performed using the diagmeta R package to suggest the optimal thresholds. RESULTS: From the search, 8 studies were selected for this systematic review. For detecting MetS risk, the optimal threshold for HGS (defined as relative HGS by adjusting for body mass) was found to be 0.422, with a sensitivity of 76.7% (95% confidence interval [CI], 64.0 to 85.8) and a specificity of 62.9% (95% CI, 56.9 to 68.5). The stratification analysis by sex resulted in optimal thresholds of 0.416 for boys and 0.376 for girls. Additionally, when the data were stratified by age, the thresholds were 0.356 for children and 0.416 for adolescents. CONCLUSIONS: Our results provide practical information for detecting high-risk groups and encouraging strength-related activities that may reduce the risk of MetS in children and adolescents.

The COVID-19 Vaccine Safety Research Center: a cornerstone for strengthening safety evidence for COVID-19 vaccination in the Republic of Korea.

The COVID-19 Vaccine Safety Research Committee (CoVaSC) was established in November 2021 to address the growing need for independent, in-depth scientific evidence on adverse events (AEs) following coronavirus disease 2019 (COVID-19) vaccination. This initiative was requested by the Korea Disease Control and Prevention Agency and led by the National Academy of Medicine of Korea. In September 2022, the COVID-19 Vaccine Safety Research Center was established, strengthening CoVaSC's initiatives. The center has conducted various studies on the safety of COVID-19 vaccines. During CoVaSC's second research year, from September 29, 2022 to July 19, 2023, the center was restructured into 4 departments: Epidemiological Research, Clinical Research, Communication & Education, and International Cooperation & Policy Research. Its main activities include (1) managing CoVaSC and the COVID-19 Vaccine Safety Research Center, (2) surveying domestic and international trends in AE causality investigation, (3) assessing AEs following COVID-19 vaccination, (4) fostering international collaboration and policy research, and (5) organizing regular fora and training sessions for the public and clinicians. Causality assessments have been conducted for 27 diseases, and independent research has been conducted after organizing ad hoc committees comprising both epidemiologists and clinical experts on each AE of interest. The research process included protocol development, data analysis, interpretation of results, and causality assessment. These research outcomes have been shared transparently with the public and healthcare experts through various fora. The COVID-19 Vaccine Safety Research Center plans to continue strengthening and expanding its research activities to provide reliable, high-quality safety information to the public.

Association between Thyroid Function and Insulin Resistance Indices in Korean Adolescents: Findings from the 2014-2015 Korea National Health and Nutrition Examination Survey.

AIM: This study investigated the sex-specific association between thyroid function and various insulin resistance (IR) indices, including noninsulin-based IR indices, in euthyroid adolescents. METHODS: A total of 465 adolescents (aged 12-18 years; 255 boys and 210 girls) based on data from the 2014-2015 Korea National Health and Nutrition Examination Survey were included. Serum thyrotropin (thyroid-stimulating hormone [TSH]) and free thyroxine (fT4) were used to assess thyroid function, whereas the homeostasis model assessment of insulin resistance (HOMA-IR), quantitative insulin-sensitivity check index (QUICKI), glucose/insulin ratio (GIR), triglyceride-glucose (TyG) index, and triglyceride/high-density lipoprotein cholesterol (TG/HDL-C) ratio were used to assess IR. The relationship between thyroid function and IR was analyzed using multiple linear regressions stratified by sex, considering obesity status. RESULTS: The relationship between thyroid function and IR varied depending on sex and was more pronounced in the overweight/obesity subgroup for both boys and girls. In overweight and obese boys and girls, fT4 was significantly associated with HOMA-IR and QUICKI with conflicting association directions. TSH was also positively associated with the TyG index in both sexes. CONCLUSIONS: The findings suggest that the relationship between thyroid function and IR in adolescents might vary depending on sex, and the degree of association was significant in obese adolescents.

Infantile allergic diseases: a cohort study prenatal fish intake and mercury exposure context.

BACKGROUND: Allergic diseases (ADs) have been increasingly reported in infants and children over the last decade. Diet, especially the inclusion of fish intake, may help to lower the risk of ADs. However, fish also, can bioaccumulate environmental contaminants such as mercury. Hence, our study aims to determine what effects the type and frequency of fish intake have on ADs in six-month-old infants, independently and jointly with mercury exposure. METHODS: This study is part of the prospective birth cohort: Mothers and Children's Environmental Health (MOCEH) study in South Korea. Data was collected on prenatal fish intake, prenatal mercury concentration and ADs for infants aged six months for 590 eligible mother-infant pairs. Logistic regression analysis was conducted to evaluate the risk of prenatal fish intake and mercury concentration on ADs in infants. Finally, interaction between fish intake and mercury concentration affecting ADs in infants was evaluated. Hazard ratios of prenatal fish intake on ADs in 6 month old infants were calculated by prenatal mercury exposure. RESULTS: Logistic regression analysis showed that white fish (OR: 0.53; 95% CI 0.30-0.94; P < 0.05) intake frequency, once a week significantly decreased the risk of ADs in infants. Stratification analysis showed that consuming white fish once a week significantly reduced the hazard of ADs (HR: 0.44; 95% CI 0.21-0.92; P < 0.05) in infants in the high-mercury (≥ 50th percentile) exposure group. CONCLUSION: The result indicates that prenatal white fish intake at least once a week reduces the risk of ADs in infants, especially in the group with high prenatal mercury exposure.

Validation of the Framingham Diabetes Risk Model Using Community-Based KoGES Data.

BACKGROUND: An 8-year prediction of the Framingham Diabetes Risk Model (FDRM) was proposed, but the predictor has a gap with current clinical standards. Therefore, we evaluated the validity of the original FDRM in Korean population data, developed a modified FDRM by redefining the predictors based on current knowledge, and evaluated the internal and external validity. METHODS: Using data from a community-based cohort in Korea (n = 5,409), we calculated the probability of diabetes through FDRM, and developed a modified FDRM based on modified definitions of hypertension (HTN) and diabetes. We also added clinical features related to diabetes to the predictive model. Model performance was evaluated and compared by area under the curve (AUC). RESULTS: During the 8-year follow-up, the cumulative incidence of diabetes was 8.5%. The modified FDRM consisted of age, obesity, HTN, hypo-high-density lipoprotein cholesterol, elevated triglyceride, fasting glucose, and hemoglobin A1c. The expanded clinical model added γ-glutamyl transpeptidase to the modified FDRM. The FDRM showed an estimated AUC of 0.71, and the model's performance improved to an AUC of 0.82 after applying the redefined predictor. Adding clinical features (AUC = 0.83) to the modified FDRM further improved in discrimination, but this was not maintained in the validation data set. External validation was evaluated on population-based cohort data and both modified models performed well, with AUC above 0.82. CONCLUSION: The performance of FDRM in the Korean population was found to be acceptable for predicting diabetes, but it was improved when corrected with redefined predictors. The validity of the modified model needs to be further evaluated.

Changes in Adolescent Health Behavior and the Exacerbation of Economic Hardship During the COVID-19 Pandemic: A Cross-sectional Study From the Korea Youth Risk Behavior Survey.

OBJECTIVES: This study investigated the association between exacerbated economic hardship during the coronavirus disease 2019 (COVID-19) pandemic and changes in the health behaviors of Korean adolescents. METHODS: We analyzed data from the 2021 Korea Youth Risk Behavior Survey and included 44 908 students (22 823 boys and 22 085 girls) as study subjects. The dependent variables included changes in health behaviors (breakfast habits, physical activity, and alcohol use) that occurred during the COVID-19 pandemic. The aggravation of economic hardship by COVID-19 and the subjective economic status of the family were used as exposure variables. Multiple logistic regression analysis was utilized to calculate the prevalence odds ratios (PORs). RESULTS: Severe exacerbation of a family's economic hardship due to COVID-19 was negatively associated with the health behaviors of adolescents, including increased breakfast skipping (POR, 1.85; 95% confidence interval [CI], 1.55 to 2.21 for boys and POR, 1.56; 95% CI, 1.27 to 1.92 for girls) and decreased physical activity (POR, 1.37; 95% CI, 1.19 to 1.57 for boys and POR, 1.38; 95% CI, 1.19 to 1.60 for girls). These negative changes in health behaviors were further amplified when combined with a low subjective family economic status. CONCLUSIONS: The experience of worsening household hardship can lead to negative changes in health behavior among adolescents. It is crucial to implement measures that address the economic challenges that arise from stressful events such as COVID-19 and to strive to improve the lifestyles of adolescents under such circumstances.

Prevalence and Burden of Human Adenovirus-Associated Acute Respiratory Illness in the Republic of Korea Military, 2013 to 2022.

BACKGROUND: Human adenovirus (HAdV) is a common cause of acute respiratory disease (ARD) and has raised significant concerns within the Korean military. Here, we conducted a comprehensive epidemiological analysis of HAdV-associated ARD by evaluating its prevalence, clinical outcomes, and prognosis. METHODS: We reviewed data from multiple sources, including the New Defense Medical Information System, Defense Medical Statistical Information System, Ministry of National Defense, Army Headquarters, Navy Headquarters, Air Force Headquarters, and Armed Forces Medical Command. We analyzed data of patients who underwent polymerase chain reaction (PCR) testing for respiratory viruses between January 2013 and July 2022 in all 14 Korean military hospitals. The analysis included the PCR test results, demographic characteristics, health care utilization, and prognosis including types of treatments received, incidence of pneumonia, and mortality. RESULTS: Among the 23,830 individuals who underwent PCR testing at Korean military hospitals, 44.78% (10,670 cases) tested positive for respiratory viruses. Across all military types and ranks, HAdV was the most prevalent virus, with a total of 8,580 patients diagnosed, among HAdV, influenza virus, human metapneumovirus, human parainfluenza virus, and human respiratory syncytial virus. HAdV-infected patients exhibited higher rates of healthcare use compared to non-HAdV-infected patients, including a greater number of emergency visits (1.04 vs. 1.02) and outpatient visits (1.31 vs. 1.27), longer hospitalizations (8.14 days vs. 6.84 days), and extended stays in the intensive care unit (5.21 days vs. 3.38 days). Furthermore, HAdV-infected patients had a higher proportion of pneumonia cases (65.79% vs. 48.33%) and greater likelihood of receiving advanced treatments such as high flow nasal cannula or continuous renal replacement therapy. CONCLUSION: Our findings indicate that HAdV posed a significant public health concern within the Korean military prior to the coronavirus disease 2019 (COVID-19) pandemic. Given the potential for a resurgence of outbreaks in the post-COVID-19 era, proactive measures, such as education, environmental improvements, and the development of HAdV vaccines, are crucial for effectively preventing future outbreaks.

Metabolically healthy obese individuals are still at high risk for diabetes: Application of the marginal structural model.

AIM: To assess the effect of obesity phenotype on the incidence of diabetes, considering phenotype as a time-varying exposure. METHODS: We used community-based cohort data from the Korean Genome and Epidemiology Study, with a 16-year follow-up period. Obesity phenotype was determined using body mass index and metabolic syndrome criteria. The influence of obesity phenotype on the occurrence of diabetes was evaluated using a Cox proportional hazard model and a marginal structural model (MSM). RESULTS: Obesity phenotypes were defined in 6265 individuals, with diabetes identified in 903 (14.4%) during the follow-up period. Individuals with metabolically healthy obesity (MHO) exhibited a higher risk of diabetes compared to those with metabolically healthy normal weight (MHNW), with a hazard ratio (HR) of 1.48 (95% confidence interval [CI] 1.15-1.90). This association remained significant after applying the MSM (HR 1.49, 95% CI 1.01-2.20). Moreover, various sensitivity analyses consistently demonstrated a higher risk of diabetes in individuals with MHO compared to those with MHNW. CONCLUSIONS: Even when obesity phenotype was treated as a time-varying exposure, individuals with MHO were still at higher risk for developing diabetes than those with MHNW. Consequently, such individuals should aim to avoid transitioning to a metabolically unfavourable state and strive to reduce their body weight to a normal range.

Prioritization of Injury Prevention and Management Programs and Research and Development (R&D) Projects: Survey Using the Delphi Technique and Analytic Hierarchy Process.

We prioritized injury prevention and management programs, and research and development (R&D) projects using the Delphi method and analytic hierarchy process (AHP) for national plan. We summarized 21 programs and 31 R&D projects based on opinions collected in the opinion survey and brainstorming. Expert panel evaluated program and project relevance in the two Delphi rounds to make consensus. Total scores were calculated by adding criterion weights calculated through the AHP multiplied by the average of scores for each program and project. The top three programs were "Integrated Management System for Injury Data," "Comprehensive Injury Surveillance System," and "Transport System Improvement Program for Major Trauma." The top three R&D projects were researches on "Identification of Vulnerable Workers Injuries to Strengthen Protections," "Data Integration on Injury and Disability," and "Using Public Health Big Data to Identify Injury Status and Risk Factors." Experts highly rated the programs to improve injury surveillance system.

Genetic predisposition, lifestyle inflammation score, food-based dietary inflammatory index, and the risk for incident diabetes: Findings from the KoGES data.

BACKGROUND AND AIMS: We investigated whether genetic predisposition, the Lifestyle Inflammation Score (LIS), or the Food-based Dietary Inflammatory Index (FDII) were associated with diabetes incidence and whether these factors interact. METHODS AND RESULTS: The study was conducted using population-based cohort data derived from the Korean Genome and Epidemiology Study, which included 6568 people aged 40-69 years. Based on 25 genetic variants related to diabetes, genetic risk scores (GRSs) were determined and LISs and FDIIs were calculated and stratified into quartiles. We investigated the effects of gene-lifestyle interactions on the incident diabetes. The multivariate Cox proportional hazard model was used to generate hazard ratios with 95 % CIs. During the 16-year follow-up period, diabetes incidence was 13.6 per 1000 person-years. A dose-response association with diabetes was observed for both GRS and LIS quartiles but not for FDII quartiles. The GRS and LIS were also independently associated with diabetes incidence in a multivariate model. Compared to the bottom quartile, the top LIS quartile and the top GRS quartile had a 2.4-fold (95 % CI, 2.0-2.8) and a 1.4-fold (95 % CI, 1.2-1.7) higher diabetes risk, respectively. However, the FDII exhibited null association. When each genetic variant was evaluated, the top versus bottom LIS quartiles exhibited heterogeneous diabetes risks for rs560887 within G6PC2, rs7072268 within HK1, and rs837763 within CDT1; however, these differences were not statistically significant in multiple comparison. CONCLUSION: Both GRS and LIS factors independently affect the incident diabetes, but their interaction effect showed insignificant association. Therefore, regardless of genetic susceptibility, more effort is needed to lower the risk for diabetes by improving lifestyle behaviors.

Metabolic complications of obesity in children and adolescents.

The global prevalence of childhood and adolescent obesity, exacerbated by the COVID-19 pandemic, is affecting not only school-aged children but also preschoolers. Early-onset obesity, along with a higher risk of metabolic complications, may contribute to a lower age of onset of cardiovascular disease (CVD). As metabolic diseases such as diabetes, dyslipidemia, and non-alcoholic fatty liver disease (NAFLD) observed in adulthood are increasingly recognized in the pediatric population, there is an emphasis on moving disease susceptibility assessment from adulthood to childhood for early detection. Unlike adults, there is a lack of consensus in the definition of metabolic diseases in children. In response to this, various indicators such as pediatric simple metabolic syndrome score (PsiMS), continuous metabolic syndrome score (cMetS), single point insulin sensitivity estimator (SPISE), and fatty liver index (FLI) have been proposed in several studies. These indicators may help explain and early detect metabolic complications associated with pediatric obesity, although more validity studies are needed. Meanwhile, obesity assessment is shifting its perspective from visual obesity to metabolic health and body composition considerations to fill the gap in health impact assessment. Sarcopenic obesity, defined as muscle-to-fat ratio (MFR), has been proposed in pediatric populations and has also been found to be associated with metabolic health in children and adolescents. The National health screening program for children in Korea has expanded but still faces limitations in laboratory testing. These tests facilitate timely intervention by identifying high-risk groups for metabolic complications. Early detection and intervention through comprehensive health screening are critical to mitigate long-term complications of childhood obesity.

Cancer risk based on alcohol consumption levels: a comprehensive systematic review and meta-analysis.

OBJECTIVES: Alcohol consumption is a well-established risk factor for cancer. Despite extensive research into the relationship between alcohol consumption and cancer risk, the effect of light alcohol consumption on cancer risk remains a topic of debate. To contribute to this discourse, we conducted a comprehensive systematic review and meta-analysis. METHODS: Our systematic review aimed to investigate the associations between different levels of alcohol consumption and the risk of several cancer types. We focused on analyzing prospective associations using data from 139 cohort studies. Among them, 106 studies were included in the meta-analysis after a quantitative synthesis. RESULTS: Our analysis did not find a significant association between light alcohol consumption and all-cause cancer risk (relative risk, 1.02; 95% confidence interval, 0.99 to 1.04), but we observed a dose-response relationship. Light alcohol consumption was significantly associated with higher risks of esophageal, colorectal, and breast cancers. Light to moderate drinking was associated with elevated risks of esophageal, colorectal, laryngeal, and breast cancers. Heavy drinking was also found to contribute to the risk of stomach, liver, pancreas, and prostate cancers, thereby increasing the risk of almost all types of cancer. Additionally, females generally had lower cancer risks compared to males. CONCLUSIONS: Our findings highlight that cancer risks extend beyond heavy alcohol consumption to include light alcohol consumption as well. These findings suggest that there is no safe level of alcohol consumption associated with cancer risk. Our results underscore the importance of public health interventions addressing alcohol consumption to mitigate cancer risks.

Association between use of vitamin and mineral supplement and non-alcoholic fatty liver disease in hypertensive adults.

Non-alcoholic fatty liver disease (NAFLD) is the most common hepatic metabolic disorder in hypertensive adults. Impaired metabolism of micronutrients may increase NAFLD risk by exacerbating oxidative stress, insulin resistance, and inflammation among hypertensive adults. In this first cross-sectional analysis of 7,376 hypertensive adults with 2,015 NAFLD cases in the Korea National Health and Nutrition Examination Survey, vitamin and mineral supplements (VMS) use was identified via questionnaire. NAFLD was defined by a hepatic steatosis index > 36. Multivariable-adjusted odds ratios (MVOR) and 95% confidence intervals (CIs) were calculated using logistic regression models. In our study, 18.6% were current users of VMS; of these, 76.7% used multi-vitamin/mineral supplements. Current VMS users had significantly lower odds of NAFLD, compared with non-users (MVOR [95% CI]: 0.73 [0.58-0.92]). The inverse association became attenuated and non-significant among those consuming VMS at higher frequency (≥ 2 times/day), for longer duration (> 16 months), and taking ≥ 2 VMS products. The inverse association with current use of VMS was only evident in those aged < 56 years (MVOR [95% CI]: 0.54 [0.40-0.72]) and men (MVOR [95% CI]: 0.56 [0.40-0.80])(Pinteraction ≤ 0.04). Our results suggest that VMS use may lower NAFLD risk, particularly among younger or male hypertensive adults, if taken in moderation.

Increase of Prevalence of Obesity and Metabolic Syndrome in Children and Adolescents in Korea during the COVID-19 Pandemic: A Cross-Sectional Study Using the KNHANES.

(1) Background: The aim of this study was to evaluate the prevalence of obesity and metabolic syndrome since the COVID-19 pandemic outbreak utilizing representative data on youth aged 2-18 years from the Korean National Health and Nutrition Examination Surveys (KNHANES) conducted in 2019-2020. (2) Methods: The survey consists of three parts: health interviews, health examinations, and nutrition surveys. From the 2019 and 2020 surveys, 1371 (2-9 years = 702 and 10-18 years = 669) and 1124 (2-9 years = 543 and 10-18 years = 581) individuals were included in the analysis. (3) Results: The mean body mass index (BMI) increased significantly among youth aged 2-9 years from 16.53 kg/m2 in 2019 to 17.1 kg/m2 in 2020 (p < 0.01). In youth aged 10-18 years, the BMI was found to increase slightly from 21.25 kg/m2 in 2019 to 21.41 kg/m2 in 2020 (p = 0.64). The increasing prevalence of extreme obesity was significant in girls, especially those aged 2-9 years (p < 0.01). However, extreme obesity had increased in 10-18-year-old boys (p = 0.08). The overall prevalence of metabolic syndrome in adolescents increased from 3.79% to 7.79% during the COVID-19 pandemic (p = 0.01). (4) Conclusions: We observed that the prevalence of obesity and metabolic syndrome among children and adolescents has increased after the COVID-19 outbreak. This is believed to be associated with an increase in the rate of early comorbidities in adulthood. The prevention of the progression of pediatric obesity has recently become an urgent public health concern in Korea.

The effect of residential greenness during pregnancy on infant neurodevelopment using propensity score weighting: A prospective mother-infant paired cohort study.

BACKGROUND: While prior studies have suggested an association between green spaces and infant neurodevelopment, the causal effect of green space exposure during pregnancy has not been fully investigated. This study aimed to identify with causal inference the effect of exposure to residential greenness during pregnancy on infants' mental-psychomotor development and the role of maternal education in modifying this association. METHODS: We prospectively collected data of pregnant women and their infants from Mothers and Children Environmental Health cohort study. Based on residential addresses, we compiled information on the percent of green space using different buffer distances (100 m, 300 m, and 500 m) and air pollution (PM2.5). Infant neurodevelopment was measured at 6 months of age using the Korean Bayley Scales of Infant Development II Mental Developmental Index (MDI) and Psychomotor Developmental Index (PDI). Generalized propensity scores (GPSs) were estimated from machine-learning (ML) algorithms. We deduced causal inference through GPS adjustment and weighting approaches. Further analyses confirmed whether the association was altered by maternal academic background. RESULTS: A total of 845 mother-infant pairs from the cohort study were included. We found that exposure to green spaces was robustly associated with infants' mental development. For example, an increase in % green space within 300 m increased the MDI by 14.32 (95 % confidence interval [CI], 3.44-25.2) in the weighting approach. Additionally, the association was even more noticeable for mothers with college degrees or above: an increase in % green space within 300 m increased the MDI by 23.69 (95 % CI, 8.53-38.85) and the PDI by 22.45 (95 % CI, 2.58-42.33) in the weighting approach. This association did not appear in mothers without college degrees. CONCLUSION: Exposure to green spaces during pregnancy showed a beneficial relationship with infant mental development. Maternal academic background could modify the impact of green space exposure on infant neurodevelopment.