Objective: We investigated the distribution of AI viruses in fecal samples from wild bird habitats (and nearby poultry-farm areas) surveyed between September and March from 2019 to 2025 and identified associated epidemiological risk factors. Methods: Samples were screened for influenza A (M, H5, H7) genes using real-time reverse transcription polymerase chain reaction (PCR), subjected to virus isolation in embryonated chicken eggs, and subtyped by PCR and sequencing. Host species were identified through DNA barcoding. Relative risks (RRs) with 95% confidence intervals were estimated for province, month, and waterfowl density. Results: Overall prevalence of HPAI and low pathogenic AI (LPAI) virus was 0.10% and 3.21%, respectively. HPAI virus was continuously isolated since 2020–2021, except 2019– 2020, while LPAI prevalence steadily increased (3.01%–4.35%). Twelve hemagglutinin (H1–H12) subtypes were identified in 1,722 isolates, and H3 (16.5%) was the most prevalent, followed by H5 (11.1%) and H7 (5.2%). LPAI H5N3 (55.7%) and H7N7 (75.5%) were the predominant H5 and H7 subtypes, respectively. Detection was higher in western coastal provinces, and higher mallard/spot-billed duck density and sampling in September– December were associated with increased risk. Conclusions and Relevance: Continued surveillance of migratory-bird habitats can provide early warning of HPAIV incursions and support targeted biosecurity measures in high-risk regions and seasons.

Background: With the aging population and advancements in medical care worldwide, the number of older patients with end-stage kidney disease continues to rise. This study aimed to identify factors associated with osteoporosis and osteopenia in older patients undergoing incident hemodialysis and assess their impact on mortality. Methods: We analyzed a large multicenter retrospective cohort of patients aged ≥70 years undergoing incident hemodialysis to identify factors associated with osteoporosis using logistic regression analysis and to assess the association of death with osteoporosis and osteopenia using Cox multivariable analysis. Results: Among 710 patients, 39.0% and 19.6% had osteoporosis and osteopenia, respectively. Osteoporosis was significantly associated with female sex, a history of fractures, and the absence of phosphate binder use. During a median follow-up of 36.8 months, 348 participants (58.8%) died. Mortality rates were the highest in the osteoporosis group (79.8%), followed by the osteopenia (77.2%) and normal bone mineral density (BMD) groups (35.2%). Cox regression analysis revealed that even after adjusting for covariates, the osteoporosis group was significantly associated with a higher mortality risk than the normal BMD group. Osteoporosis at the start of hemodialysis was significantly associated with higher mortality. Conclusion We should consider the importance of bone health in patients undergoing incident hemodialysis and pay attention to the use of phosphate binders and fracture prevention.

Background: Obesity is a well-known risk factor for chronic kidney disease and its progression. However, the impact of obesity on the renal function of the elderly population is uncertain. We investigated the association between obesity and renal outcomes in the elderly. Methods: We analyzed 130,504 participants from the Korean National Health Insurance Service-Senior cohort. Obesity was classified according to body mass index (BMI), sex-specific waist circumference (WC), and the presence of metabolic syndrome. The primary outcome was renal function decline, defined as a decline in the estimated glomerular filtration rate (eGFR) of at least 50% from baseline or new-onset end-stage renal disease. Results: During a follow-up period of 559,531.1 person-years (median, 4.3 years), 2,486 participants (19.0%; incidence rate of 4.44 per 1,000 person-years) showed renal function decline. A multivariate Cox proportional hazards model revealed that BMI/WC was not associated with renal function decline. However, the group with metabolic syndrome had a significantly increased risk of renal function decline compared to the group without metabolic syndrome (adjusted hazard ratio [HR], 1.24; 95% confidence interval [CI], 1.13–1.36). Compared with the non-metabolic syndrome group, the adjusted HRs (95% CI) for participants with one through five components were 0.96 (0.84–1.11), 1.10 (0.96–1.27), 1.24 (1.06–1.45), 1.37 (1.12–1.66), and 1.99 (1.42–2.79), respectively (p for trend < 0.001). Conclusion In elderly Korean adults, metabolic syndrome and the number of its components were associated with a higher risk of renal function decline, but BMI or WC was not significant.

Background: and Purpose: Given the irreversible nature of dementia, this study examined the effects of a 20-week exercise-based dementia prevention program in community-dwelling older adults, focusing on prior exercise experience and program adherence. Methods: In this exploratory, non-randomized trial, 55 older adults (65–79 years) were allocated to an intervention (n=26) or control (n=29) group, and blinding was not feasible.The intervention comprised supervised rhythmic aerobic exercise with cognitive-motor components performed three times per week. Cognition was the primary outcome, and secondary outcomes included physical fitness, blood pressure, and blood biomarkers.Subgroup analyses classified participants by prior exercise experience and intervention exposure: G1 and G2 comprised control subgroups with no intervention exposure, whereas G3 and G4 comprised intervention-exposed subgroups stratified by adherence. Results: No significant group-by-time interactions were observed for cognitive outcomes.Participants with prior exercise experience and low adherence (G2) showed significant improvement on the Korean Mini-Mental State Examination (β=1.66, p=0.024) despite declines in physical fitness, whereas higher adherence in G3–G4 was associated with stable or favorable physical performance, with G4 showing a positive trend in the 30-second sit-tostand test. Systolic blood pressure decreased significantly in G2–G4. Conclusions Although overall cognitive gains were modest and not group specific, prior exercise experience and sustained adherence were associated with favorable changes in physical fitness and vascular outcomes, suggesting that tailored multicomponent exercise programs and long-term engagement may help promote cognitive health in older adults.

Background: and Purpose: Tailored physical exercise interventions have the potential to promote cognitive health in older adults and offer significant advantages for those more vulnerable to decline. The specific relationship between physical fitness and cognition among the elderly has not been clearly established. The purpose of this investigation was to assess the relationship between physical fitness and cognitive function in older Korean adults. Methods: Eighty-four community-dwelling older adults (mean age: 70.7±5.3 years; 81.0% female) completed a standardized physical fitness battery assessing handgrip strength, sit-and-reach, 30-second sit-to-stand, 2-minute stationary march, 3-m sit-walk-and-return, figure-8-walk, and T-wall response time. Cognitive function was evaluated using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Descriptive statistics, partial correlation analyses, and stepwise multiple linear regression were conducted. Results: Slower T-wall response time was significantly correlated with lower RBANS total index, immediate memory, and delayed memory scores. In regression models, slower T-wall response time was independently associated with lower RBANS total index (β=−0.234, p=0.026) and delayed memory scores (β=−0.295, p=0.029). The regression model for immediate memory was not statistically significant overall; therefore, no predictive conclusion was drawn for this domain. Higher education showed a significant positive association with cognitive performance. Conclusions Coordination, as measured by T-wall response time, emerged as the only physical fitness component consistently associated with cognitive performance in older adults. Coordination-related fitness may be an important correlate of cognitive function in older adults and a promising target for future exercise interventions.

Janus kinase (JAK) inhibitors are an important treatment option for ulcerative colitis, providing rapid onset of action, oral administration, and efficacy even after biologic failure. The 3 approved agents—tofacitinib, filgotinib, and upadacitinib—differ in JAK isoform selectivity, leading to clinically meaningful differences in efficacy and safety. Evidence from network meta-analyses, clinical trials, and real-world studies consistently shows that upadacitinib provides the highest efficacy for induction and maintenance of remission, whereas filgotinib demonstrates the most favorable safety profile. The strong efficacy of upadacitinib and tofacitinib is particularly relevant in patients with severe disease, including acute severe ulcerative colitis, and upadacitinib maintains high efficacy regardless of prior advanced therapy exposure. JAK inhibitors also benefit extraintestinal manifestations. Although risks such as herpes zoster, serious infection, thromboembolism, and major cardiovascular events differ among agents, long-term data suggest generally acceptable safety when used appropriately. Intraclass JAK-to-JAK cycling is feasible, with about half of patients achieving steroid-free clinical remission in retrospective cohorts. Based on mechanistic, clinical, and real-world evidence, filgotinib may be a first-line option for patients with lower disease activity or when safety is a priority, whereas upadacitinib or tofacitinib may be preferred in higher disease activity. Strategically selecting agents may improve durability and outcomes.

Background: Cough is a prominent symptom of chronic respiratory diseases, including asthma, idiopathic pulmonary fibrosis (IPF), chronic obstructive pulmonary disease (COPD), and bronchiectasis (BE). Some patients develop chronic cough (CC), defined as lasting more than 8 weeks, yet its characteristics remain poorly understood. This study aimed to characterize CC across various chronic respiratory diseases using validated cough assessment tools. Methods: The Cough Assessment in Chronic Respiratory Diseases (COASESS) study, a multicenter, prospective cross-sectional study, was conducted at 10 university hospitals. CC was evaluated in terms of intensity (numeric rating scale [NRS]), frequency (cough symptom score [CSS]), and quality of life (using the cough assessment test [COAT] and Leicester cough questionnaire [LCQ]). Cough hypersensitivity was assessed with the cough hypersensitivity questionnaire (CHQ). Data on age, sex, and smoking status were also collected. Results: Among the 303 enrolled patients, 266 with chronic respiratory diseases were included in the analysis. Patients with asthma were younger, predominantly female, and non-smokers, whereas those with COPD and IPF were older males who had previously smoked (p<0.001). Scores for COAT, LCQ, NRS, and CSS showed significant differences across the diseases, with asthma and IPF patients experiencing a greater symptom burden and lower quality of life compared to those with COPD or BE (p<0.001). Although CHQ total scores were similar across groups, asthma patients more frequently reported triggers such as talking and post-nasal drip. Conclusion This study revealed distinct characteristics of CC across different chronic respiratory diseases. Asthma and IPF were associated with a higher symptom burden, and cough hypersensitivity varied depending on the underlying condition. These findings highlight the necessity for disease-specific assessments and management strategies for CC.

In patients with differentiated thyroid cancer (DTC), initial recurrence risk stratification based on clinical, histopathological, and perioperative data remains the key determinant for guiding management strategies during the first 1-2 years post-treatment. However, the adoption of ongoing risk stratification (ORS), which dynamically reassesses risk by integrating longitudinal clinical data and treatment response, enables more precise long-term prognostic assessment and facilitates highly individualized management. Building upon recent guidelines, the 2026 KTA guideline has been further refined by incorporating robust evidence from large-scale national cohorts and comprehensive systematic reviews. These updated recommendations outline contemporary concepts of ORS, risk-adapted TSH suppression targets, optimized surveillance modalities for recurrence detection, and disease-specific long-term follow-up strategies. Reflecting the paradigm shift toward de-escalated treatment, this revision integrates evolved perspectives on TSH suppression intensity, the clinical interpretation of thyroglobulin levels, and tailored follow-up intervals. These evidence-based recommendations aim to minimize unnecessary treatment and excessive surveillance in the large proportion of patients with excellent prognosis after initial therapy, while ensuring that each patient receives appropriately tailored and effective long-term management.

Vaccines are highly effective, but rare or delayed adverse events following immunization (AEFIs) require post-licensure surveillance beyond clinical trials. Korea lacks a comprehensive, active, database-based framework, yet key assets exist: nationwide claims databases (National Health Insurance Service/Health Insurance Review and Assessment Service), the national immunization registry (Korea Disease Control and Prevention Agency’s Immunization Registry Information System) for National Immunization Program (NIP) and non-NIP vaccines, and increasingly standardized hospital electronic health records.We propose a federated, code to data architecture with data linkages between these data.Implementation should adopt a common data model (CDM), standardized case definitions, latency accounting, and transparent public reporting under strong privacy governance. Major challenges include multi step administrative approvals for data linkage, incomplete capture of adult non-NIP vaccinations, heterogeneous hospital data structures, and strict data protection constraints. Strategic priorities are to streamline statutory and administrative processes for public health use, mandate or enable claims-based capture of adult vaccinations, enhance CDM based interoperability, and develop secure hubs for aggregated outputs. With these measures, Korea will be well positioned to establish a scalable active surveillance system capable of detecting rare AEFIs, supporting transparent and evidence-based communication, and ensuring equitable injury compensation grounded in domestic data.

Background: This study examined the relationship between work-related physical workload and knee cartilage loss using magnetic resonance imaging (MRI) among farmers and fishers in the Republic of Korea. Methods: Bilateral knee MRI and questionnaire data from 545 farmers and 204 fishers aged 40—79 years were analyzed. Cartilage damage was evaluated using the MRI Osteoarthritis Knee Score (MOAKS). Mean cartilage loss scores were compared by sex, age, and body mass index (BMI). Analysis of covariance (ANCOVA) was used to assess associations of cumulative squatting work time (CSWT, hours) and cumulative lifting work time (CLWT, hours) with cartilage loss, adjusting for age and BMI, and stratified by sex. Results: Age was the most significant factor associated with cartilage loss, whereas BMI was not. In women, CSWT was significantly associated with medial cartilage loss in the tibiofemoral (TF) joint after adjusting for age and BMI (right: p = 0.036; left: p = 0.021). The CLWT was significantly associated with cartilage loss in the right patellofemoral joint (right: p = 0.005; left: p = 0.051). In men, CLWT showed a significant association only in the right medial TF joint (p = 0.046). Conclusion Among Korean farmers and fishers, cumulative squatting and lifting workloads were associated with knee cartilage damage in a compartment- and sex-specific manner.