Background: and Purpose The pain lateralization in cluster headache (CH) may be related to the asymmetry in the functions of the brain hemispheres. The right-sided dominance of pain in CH has been found inconsistently across studies, and so we aimed to characterize this and identify the factors influencing pain lateralization during current and previous bouts. Methods: This study enrolled 227 patients from the Korean Cluster Headache Registry between October 2018 and December 2020. We evaluated the side of pain during current and previous bouts, demographic features, and clinical characteristics, including handedness. Multivariable logistic regression analyses were performed to identify factors associated with the side of pain. Results: The 227 patients with CH included 131 (57.7%) with right-sided pain and 86 (37.9%) with left-sided pain during the current bout (p<0.001). The 189 patients with previous bouts of CH included 86.8% who consistently reported the same side of pain throughout multiple bouts (side-locked pain), with a higher prevalence of pain on the right than the left side (55.0% vs. 31.7%, p<0.001). Multivariable analyses revealed that higher age at diagnosis (odds ratio [OR]=1.045, p=0.031) and shorter CH attacks (OR=0.992, p=0.017) were associated with left-side-locked pain. However, handedness was not associated with the lateralization of leftside-locked pain. Conclusions This study has confirmed the predominance of right-sided pain throughout multiple CH bouts. We found that higher age at diagnosis and shorter CH attacks were associated with left-side-locked pain, suggesting that certain clinical factors are associated with the pain laterality. However, the underlying mechanisms linking these factors to lateralized pain remain unclear and therefore require further investigation.

Background: and Purpose The pain lateralization in cluster headache (CH) may be related to the asymmetry in the functions of the brain hemispheres. The right-sided dominance of pain in CH has been found inconsistently across studies, and so we aimed to characterize this and identify the factors influencing pain lateralization during current and previous bouts. Methods: This study enrolled 227 patients from the Korean Cluster Headache Registry between October 2018 and December 2020. We evaluated the side of pain during current and previous bouts, demographic features, and clinical characteristics, including handedness. Multivariable logistic regression analyses were performed to identify factors associated with the side of pain. Results: The 227 patients with CH included 131 (57.7%) with right-sided pain and 86 (37.9%) with left-sided pain during the current bout (p<0.001). The 189 patients with previous bouts of CH included 86.8% who consistently reported the same side of pain throughout multiple bouts (side-locked pain), with a higher prevalence of pain on the right than the left side (55.0% vs. 31.7%, p<0.001). Multivariable analyses revealed that higher age at diagnosis (odds ratio [OR]=1.045, p=0.031) and shorter CH attacks (OR=0.992, p=0.017) were associated with left-side-locked pain. However, handedness was not associated with the lateralization of leftside-locked pain. Conclusions This study has confirmed the predominance of right-sided pain throughout multiple CH bouts. We found that higher age at diagnosis and shorter CH attacks were associated with left-side-locked pain, suggesting that certain clinical factors are associated with the pain laterality. However, the underlying mechanisms linking these factors to lateralized pain remain unclear and therefore require further investigation.

Background: and Purpose The pain lateralization in cluster headache (CH) may be related to the asymmetry in the functions of the brain hemispheres. The right-sided dominance of pain in CH has been found inconsistently across studies, and so we aimed to characterize this and identify the factors influencing pain lateralization during current and previous bouts. Methods: This study enrolled 227 patients from the Korean Cluster Headache Registry between October 2018 and December 2020. We evaluated the side of pain during current and previous bouts, demographic features, and clinical characteristics, including handedness. Multivariable logistic regression analyses were performed to identify factors associated with the side of pain. Results: The 227 patients with CH included 131 (57.7%) with right-sided pain and 86 (37.9%) with left-sided pain during the current bout (p<0.001). The 189 patients with previous bouts of CH included 86.8% who consistently reported the same side of pain throughout multiple bouts (side-locked pain), with a higher prevalence of pain on the right than the left side (55.0% vs. 31.7%, p<0.001). Multivariable analyses revealed that higher age at diagnosis (odds ratio [OR]=1.045, p=0.031) and shorter CH attacks (OR=0.992, p=0.017) were associated with left-side-locked pain. However, handedness was not associated with the lateralization of leftside-locked pain. Conclusions This study has confirmed the predominance of right-sided pain throughout multiple CH bouts. We found that higher age at diagnosis and shorter CH attacks were associated with left-side-locked pain, suggesting that certain clinical factors are associated with the pain laterality. However, the underlying mechanisms linking these factors to lateralized pain remain unclear and therefore require further investigation.

Background/Aims: Blocking the complement system is a promising strategy to impede the progression of metabolic dysfunction–associated steatotic liver disease (MASLD). However, the interplay between complement and MASLD remains to be elucidated. This comprehensive approach aimed to investigate the potential association between complement dysregulation and the histological severity of MASLD. Methods: Liver biopsy specimens were procured from a cohort comprising 106 Korean individuals, which included 31 controls, 17 with isolated steatosis, and 58 with metabolic dysfunction–associated steatohepatitis (MASH). Utilizing the Infinium Methylation EPIC array, thorough analysis of methylation alterations in 61 complement genes was conducted. The expression and methylation of nine complement genes in a murine MASH model were examined using quantitative RT-PCR and pyrosequencing. Results: Methylome and transcriptome analyses of liver biopsies revealed significant (p<0.05) hypermethylation and downregulation of C1R, C1S, C3, C6, C4BPA<, and SERPING1, as well as hypomethylation (p<0.0005) and upregulation (p<0.05) of C5AR1, C7, and CD59, in association with the histological severity of MASLD. Furthermore, DNA methylation and the relative expression of nine complement genes in a MASH diet mouse model aligned with human data. Conclusions Our research provides compelling evidence that epigenetic alterations in complement genes correlate with MASLD severity, offering valuable insights into the mechanisms driving MASLD progression, and suggests that inhibiting the function of certain complement proteins may be a promising strategy for managing MASLD.

Background: and Purpose Patients with cluster headache (CH) exhibit impaired health-related quality of life (HRQoL). However, there have been few studies related to the HRQoL of patients with CH from Asian backgrounds. This study aimed to determine the impact of CH on HRQoL and to identify the factors affecting HRQoL in patients with CH during cluster periods. Methods: This prospective study enrolled patients with CH from 17 headache clinics in South Korea between September 2016 and February 2021. The study aimed to determine HRQoL in patients with CH using the EuroQol 5 Dimensions (EQ-5D) index and the time trade-off (TTO) method. Age- and sex-matched headache-free participants were recruited as a control group. Results: The study included 423 patients with CH who experienced a cluster period at the time. EQ-5D scores were lower in patients with CH (0.88±0.43, mean±standard deviation) than in the controls (0.99±0.33, p<0.001). The TTO method indicated that 58 (13.6%) patients with CH exhibited moderate-to-severe HRQoL deterioration. The HRQoL states in patients with CH were associated with current smoking patterns, headache severity, frequency, and duration, and scores on the Generalized Anxiety Disorder 7-item scale (GAD-7), Patient Health Questionnaire 9-item scale (PHQ-9), 6-item Headache Impact Test, and 12-item Allodynia Symptom Checklist. Multivariable logistic regression analyses demonstrated that the HRQoL states in patients with CH were negatively correlated with the daily frequency of headaches, cluster period duration, and GAD-7 and PHQ-9 scores. Conclusions Patients with CH experienced a worse quality of life during cluster periods compared with the headache-free controls, but the degree of HRQoL deterioration varied among them. The daily frequency of headaches, cluster period duration, anxiety, and depression were factors associated with HRQoL deterioration severity in patients with CH.

In the 2023–2024 season, the influenza epidemic in South Korea peaked earlier than in recent years. In this study, we aimed to estimate the interim vaccine effectiveness (VE) of the influenza vaccination to prevent influenza during the early season. From November 1, 2023, to December 31, 2023, we enrolled 2,632 subjects with influenza-like illness from eight hospitals participating in hospital-based influenza morbidity and mortality surveillance. A retrospective test-negative case-control study was conducted to estimate the VE. The results showed an adjusted VE of 22.5% (95% confidence interval [CI], 6.6 to 35.8) for the total population. The adjusted VE was 22.3% (95% CI, 6.1 to 35.7) for influenza A and 9.4% (95% CI, −51.3 to 45.7) for influenza A/H1N1. Full results of the analysis will be reported.

Background: Bivalent booster mRNA vaccines containing the omicron-variant strains have been introduced worldwide in the autumn of 2022. Nevertheless, the omicron subvariants evoked another large coronavirus disease 2019 (COVID-19) pandemic wave in late 2022 and early 2023. Methods: A retrospective, test-negative, case-control study was conducted to estimate the vaccine effectiveness (VE) of bivalent COVID-19 vaccines in 8 university hospitals between January and February 2023. The case and control groups were divided based on nasopharyngeal COVID-19 real-time polymerase chain reaction results and matched based on age, sex, hospital, and date (week) of the test performed. The VE of the BA.1- or BA.4/BA.5-based mRNA vaccines were estimated. VE was calculated using the 1−adjusted odds ratio from multivariable logistic regression. Results: In total, 949 patients and 947 controls were enrolled in this study. VE for the BA.4/ BA.5-based bivalent mRNA vaccine was 43% (95% confidence interval [CI], 17, 61%). In subgroup analysis based on age and underlying medical conditions, BA.4/BA.5-based bivalent mRNA vaccine was effective against old adults aged ≥ 65-years (VE, 55%; 95% CI, 23, 73%) and individuals with comorbidities (VE, 54%; 95% CI, 23, 73%). In comparison, the BA.1-based bivalent mRNA vaccine did not demonstrate statistically significant effectiveness (VE, 25%; 95% CI, −8, 49%). Conclusion The BA.4/BA.5-based bivalent mRNA booster vaccine provided significant protection against COVID-19 in the Korean adults, especially in the older adults aged ≥ 65 years and in individuals with underlying medical conditions.

This report presents the latest statistics on the stroke population in South Korea, sourced from the Clinical Research Collaborations for Stroke in Korea-National Institute for Health (CRCS-K-NIH), a comprehensive, nationwide, multicenter stroke registry. The Korean cohort, unlike western populations, shows a male-to-female ratio of 1.5, attributed to lower risk factors in Korean women. The average ages for men and women are 67 and 73 years, respectively.Hypertension is the most common risk factor (67%), consistent with global trends, but there is a higher prevalence of diabetes (35%) and smoking (21%). The prevalence of atrial fibrillation (19%) is lower than in western populations, suggesting effective prevention strategies in the general population. A high incidence of large artery atherosclerosis (38%) is observed, likely due to prevalent intracranial arterial disease in East Asians and advanced imaging techniques.There has been a decrease in intravenous thrombolysis rates, from 12% in 2017–2019 to 10% in 2021, with no improvements in door-to-needle and door-to-puncture times, worsened by the coronavirus disease 2019 pandemic. While the use of aspirin plus clopidogrel for noncardioembolic stroke and direct oral anticoagulants for atrial fibrillation is well-established, the application of direct oral anticoagulants for non-atrial fibrillation cardioembolic strokes in the acute phase requires further research. The incidence of early neurological deterioration (13%) and the cumulative incidence of recurrent stroke at 3 months (3%) align with global figures. Favorable outcomes at 3 months (63%) are comparable internationally, yet the lack of improvement in dependency at 3 months highlights the need for advancements in acute stroke care.

Background: Several cases of pediatric acute hepatitis of unknown etiology related to adenoviral infections have been reported in Europe since January 2022. The aim of this study was to compare the incidence, severity, possible etiology, and prognosis of the disease with those in the past in Korea. Methods: The surveillance group collected data between May and November 2022 using a surveillance system. Acute hepatitis of unknown etiology was defined in patients aged < 16 years with a serum transaminase level > 500 IU/L, not due to hepatitis A-E or other underlying causes. For comparison, data from 18 university hospitals were retrospectively collected as a control group between January 2021 and April 2022. Results: We enrolled 270 patients (mean age, 5 years). The most common symptom was fever. However, the incidence was similar between 2021 and 2022. Liver function test results, number of patients with acute liver failure (ALF), liver transplantation (LT), death, and adenovirus detection rates did not differ between the two groups. None of the adenoviruspositive patients in either group experienced ALF, LT, or death. In the surveillance group, adenovirus-associated virus-2 was detected in four patients, one of whom underwent LT. Patients with an unknown etiology showed significantly higher bilirubin levels, a lower platelet count, and a higher LT rate than patients with a possible etiology. Conclusion The incidence of pediatric acute hepatitis of unknown etiology and adenovirus detection rate have not increased in Korea.

Osteoporosis and osteoporotic fractures cause socioeconomic concerns, and medical system and policies appear insufficient to prepare for these issues in Korea, where the older adult population is rapidly increasing. Many countries around the world are already responding to osteoporosis and osteoporotic fractures by adopting fracture liaison service (FLS), and such an attempt has only begun in Korea. In this article, we introduce the operation methods for institutions implementing FLS and characteristics of services, and activities of the FLS Committee for FLS implementation in the Korean Society for Bone and Mineral Research. In addition, we hope that the current position statement will contribute to the implementation of FLS in Korea and impel policy changes to enable a multidisciplinary and integrated FLS operated under the medical system.