1.Beyond Weight Loss: Skeletal Considerations in Obesity Treatment
Endocrinology and Metabolism 2026;41(2):210-221
The rapid evolution of obesity therapeutics, led by glucagon-like peptide-1 receptor agonists (GLP-1RAs) and metabolic surgery, has achieved unprecedented weight loss. However, the skeletal consequences of such substantial weight reduction are of increasing clinical concern. This review explores the relationship between obesity, weight-loss modalities, and bone health. While obesity was historically viewed as bone-protective due to mechanical loading, recent evidence highlights qualitative bone deterioration and sitespecific fracture risks. Intentional weight loss through caloric restriction or bariatric surgery consistently accelerates bone turnover and reduces bone mineral density (BMD), with surgical interventions showing the most significant impact. Emerging data on GLP-1RAs suggest modest BMD declines, largely proportional to weight loss and likely driven by mechanical unloading. Conversely, preclinical studies indicate that GLP-1 signaling may exert direct osteoanabolic and anti-resorptive effects. To preserve skeletal integrity, obesity management must shift toward a holistic body composition framework. Integrating structured resistance exercise, optimizing nutrition (calcium, vitamin D, and protein), and implementing skeletal monitoring in high-risk individuals are essential. Future obesity care should prioritize the maintenance of bone quality and lean mass alongside fat reduction to ensure long-term skeletal resilience and prevent fragility fractures.
2.Plan and operations of the 10th Korea National Health and Nutrition Examination Survey (2025–2027)
Sun-Ja KIM ; Sihyun PARK ; Sunja KIM ; Suyeon PARK ; Yoonjung KIM ; Yunjung CHOI ; Sungha YUN ; Kyungwon OH
Epidemiology and Health 2026;48(1):e2026001-
The Korea National Health and Nutrition Examination Survey (KNHANES) is a national health survey mandated by Article 16 of the National Health Promotion Act to assess the health and nutritional status of the Korean population. Over the past 2 decades, the survey has continuously introduced timely survey components while strengthening its survey methodology and operational systems to enhance both the policy relevance and scientific utility of its findings. The 10th KNHANES (2025–2027) preserves the statistical representativeness of its sampling design while expanding the use of web-based self-administered questionnaires to improve participant convenience. In response to Korea’s transition into a super-aged society, the 10th KNHANES incorporates enhanced older-adult health surveys, including osteoporosis assessment and older adults’ life functioning, and newly introduces items addressing social support as part of the social determinants of health. In addition, a longitudinal follow-up survey system has been established to monitor long-term changes in population health. Collectively, these changes are expected to improve understanding of aging-related health issues, support evidence-based national health policy development, and expand the applicability of KNHANES data for academic research.
3.Cohort profile: Korean Varicella Immunization Monitoring (K-VIM) Scheme: a national cohort of children born 2011–2022
Young Kyu SHIM ; Young Hwa LEE ; Young June CHOE ; Yoonsun YOON ; Yun-Kyung KIM
Epidemiology and Health 2026;48(1):e2026005-
Varicella, caused by the varicella-zoster virus, was once nearly universal in childhood before the advent of vaccination and may lead to severe complications and even fatalities. Monitoring varicella vaccine effectiveness is crucial yet often overlooked in settings with limited surveillance infrastructure. The Korean Varicella Immunization Monitoring (K-VIM) Scheme was established to address this gap by assembling a national, insurance-based birth cohort of children born between 2011 and 2022 (n=4,505,165). This cohort leverages comprehensive healthcare databases in Korea to capture vaccination records, medical visits, and varicella infection outcomes for virtually all children within the target birth years. We describe the enrollment and key characteristics of the K-VIM cohort, including vaccination coverage, demographic features, and varicella incidence to date. The structure and completeness of Korea’s national health insurance and immunization registries enable robust longitudinal tracking of varicella infections among vaccinated versus unvaccinated children. Early findings demonstrate distinct patterns in infection rates and disease severity according to vaccination status. The K-VIM Scheme provides a foundation for ongoing epidemiological studies of varicella vaccine effectiveness and public health impact in Korea. Future plans include evaluating the long-term effects of varicella vaccination, including potential impacts on herpes zoster incidence, using diverse study designs to strengthen causal inference and inform immunization policy.
4.Protective Effect of Brain Derived Neurotrophic Factor-Overexpressing Wharton’s Jelly-Derived Mesenchymal Stromal Cells in Severe Intraventricular Hemorrhage in Newborn Rats
So Yeon JUNG ; Misun YANG ; Young Eun KIM ; Dong Kyung SUNG ; Se In SUNG ; Chang-Woo LEE ; Yun Sil CHANG ; So Yoon AHN
International Journal of Stem Cells 2026;19(1):54-65
The brain-derived neurotrophic factor (BDNF) plays a crucial role in neuroprotection, and we have previously demonstrated BDNF-mediated neuroprotective effects in mesenchymal stromal cells (MSCs). The present study aimed to investigate whether BDNF-overexpressing MSCs enhance the therapeutic efficacy of naïve MSCs in a preclinical model of severe neonatal intraventricular hemorrhage (IVH). We exposed primary rat neuronal cells to 40 U of thrombin overnight in vitro. Subsequently, the neuronal cells were co-cultured with either naïve MSCs or BDNF-overexpressing MSCs (1×105 cells in 1 mL media) for 24 hours. Next, 300 μL of maternal blood was injected into bilateral ventricles on postnatal day (P)4 to induce severe IVH in newborn Sprague-Dawley male rats. At P6, either naïve MSCs or BDNF-overexpressing MSCs (1×105 cells in 10 μL saline) were transplanted intraventricularly. Behavioral function tests, including passive avoidance, followed by endpoint analyses of brain tissue and cerebrospinal fluid were performed at P35. BDNF-overexpressing MSCs enhanced the effects of naïve MSCs against cell death, cytotoxicity, and oxidative stress in vitro. Notably, naïve and BDNF-overexpressing MSCs did not attenuate post-hemorrhagic ventricular dilatation, neuronal cell death, or gliosis. However, BDNF-overexpressing MSCs attenuated microglial activation.Furthermore, inflammatory cytokine (interleukin [IL]-1α, IL-1β, IL-6, and tumor necrosis factor-α) levels and memory function assessed using a passive avoidance test significantly improved in the BDNF-overexpressing MSC transplanted group compared with the naïve MSC transplanted group. Our data suggest that BDNF-overexpressing MSCs may offer superior protective effects to naïve MSCs in a neonatal IVH model.
5.Risk Factors and Clinical Characteristics of Graves’ Ophthalmopathy: a Retrospective Multicenter Study in Korea
Yoon Young CHO ; Hyunju PARK ; Jung HEO ; Jiyeon AHN ; Min Kyung LEE ; Jae Hyuk LEE ; Ju-Yuen LEE ; Yun Jin KIM ; Seo Young SOHN
International Journal of Thyroidology 2026;19(1):85-94
Background and Objectives:
Graves’ ophthalmopathy (GO) is an autoimmune inflammatory disorder that can adversely affect quality of life in patients with Graves’ disease (GD). The objective of this study was to characterize the clinical features of patients with GO and to identify risk factors associated with its development and the need for anti-inflammatory treatment.
Materials and Methods:
In this multicenter, retrospective observational study, 818 patients with GD were identified via electronic medical record review. Clinical characteristics were assessed, and logistic regression analyses were performed to identify risk factors for GO development and the need for anti-inflammatory treatment.
Results:
Among the 818 patients with GD, 135 (16.5%) developed GO, and 60 (7.3%) of these patients received anti-inflammatory treatment. GO was diagnosed at the time of GD diagnosis in 54.8% of cases, and proptosis and eyelid/orbital swelling were the common presenting features. In multivariable analysis, female sex (odds ratio [OR]: 1.75, confidence interval [CI]: 1.02-3.03), goiter (OR: 1.71, CI: 1.08-2.71), and smoking (ex-smokers: OR, 2.18; 95% CI: 1.02-4.65; current smokers: OR, 3.11; CI, 1.78-5.44) were independently associated with GO development, whereas diabetes (OR: 0.35, CI: 0.14-0.89) was inversely associated. Higher total cholesterol (OR: 1.31, CI: 1.01-1.04) and elevated thyrotropin-binding inhibitory immunoglobulin levels (OR: 1.07, CI: 1.02-1.11) were also significantly associated with the need for anti-inflammatory treatment.
Conclusion
This study delineated the clinical features of GO and identified risk factors for its development and the need for anti-inflammatory treatment in patients with GD, providing valuable information for the management of GO in Korean patients.
6.Influence of Incidental Pulmonary Nodules on Surgical Decision-Making in Thyroid Cancer: a Nationwide Survey
Ja Kyung LEE ; Sukmin YUN ; Eunji KIM ; Yoon KONG ; Hyeong Won YU ; Min Joo KIM ; Jae Hoon MOON ; June Young CHOI
International Journal of Thyroidology 2026;19(1):68-77
Background and Objectives:
The clinical significance of incidental pulmonary nodules detected during thyroid cancer evaluation remains unclear. This study aimed to investigate how such findings affect surgical decisionmaking and whether management differs by physician characteristics.
Materials and Methods:
A web-based survey was distributed to 722 active members of the Korean Thyroid Association in March 2025. Eligible participants included board-certified endocrinologists, endocrine surgeons, and otolaryngologists actively treating thyroid cancer. The questionnaire included clinical scenarios featuring incidental lung nodules found during thyroid cancer work-up, with respondents asked to choose preferred surgical extent (thyroid lobectomy vs. total thyroidectomy) and management approaches.
Results:
Out of 72 physicians who completed the survey, half (n=36, 50.0%) of the respondents answered that the presence of incidental lung nodules could influence their decision on thyroidectomy extent. Among those influenced by lung nodules, 86.1% recommended total thyroidectomy in patients with high- or intermediate-risk thyroid cancer, while 11.1% would do so for all thyroid cancer patients.Endocrinologists, compared to surgeons, were more likely to choose total thyroidectomy in patients with preoperative incidental lung nodules (78.3% vs. 36.7%, p=0.001).
Conclusion
Incidental lung nodules may influence surgical planning in clinicians due to the risk of micrometastasis from thyroid cancer. Endocrinologists tend to favor a more extensive surgical approach compared to surgeons, reflecting greater concern for potential metastatic disease. These findings underscore the need for multidisciplinary consensus guidelines for the management of incidental pulmonary nodules in thyroid cancer patients.
7.Delayed Bleeding With Variable Presentations in Implant-Based Breast Reconstruction During Adjuvant Ado-Trastuzumab Emtansine (Kadcyla) Therapy: Two Case Reports
Seong Jun RYU ; Young Seok KIM ; In Sik YUN ; Kyunghyun MIN ; Joon JEONG ; Tai Suk ROH
Journal of Breast Cancer 2026;29(2):192-201
Ado-trastuzumab emtansine (T-DM1) is an effective adjuvant therapy for human epidermal growth factor receptor 2-positive breast cancer; however, its surgical safety profile remains unclear. We observed delayed bleeding with variable and often subtle clinical manifestations during implant-based breast reconstruction (IBBR). Two patients who received adjuvant T-DM1 therapy after IBBR were retrospectively reviewed. The patient in Case 1 developed a recurrent seroma and liquefied hematoma requiring repeated aspirations, with platelet counts decreasing from 218 × 109 /L to 33 × 109 /L before expander removal.The patient in Case 2 experienced an acute massive hematoma on postoperative day (POD) 2, prior to T-DM1 initiation, which resolved after re-exploration; a temporally distinct delayed hemorrhagic event occurred on POD 175 during T-DM1 therapy after radiotherapy, accompanied by a platelet nadir of 34 × 109 /L. Both patients required plateletpheresis and prolonged drainage. Delayed bleeding during T-DM1 therapy may reflect a combination of hematological suppression and vascular vulnerability. Therefore, vigilant surveillance and cautious postoperative rehabilitation are warranted.
8.Nationwide Trends in Coronary Artery Bypass Grafting in the Republic of Korea, 2005–2022: A Comparison with International Data
Min Ho JU ; Jun Ho LEE ; Yun Jin KIM ; Ho Jin KIM ; Ho Young HWANG ; Sang Yoon YEOM ; Hee Jung KIM ; Young-Nam YOUN ; Wook Sung KIM ; Man-Jong BAEK ; Hyun Keun CHEE ;
Journal of Chest Surgery 2026;59(1):7-16
Coronary artery bypass grafting (CABG) remains a key revascularization strategy for ischemic heart disease; however, nationwide trends in the Republic of Korea have not been thoroughly investigated. Using data from the Korean National Health Insurance Service, we analyzed adult patients who underwent isolated CABG between 2005 and 2022. We evaluated surgical volume, patient demographics, procedural strategies (off-pump vs. onpump), and outcomes. International comparisons were conducted using national cardiac surgery registry data. A total of 51,923 CABG cases were identified. Annual surgical volume declined until 2013 but gradually increased thereafter, reaching 3,717 cases in 2022. Despite this recovery, Korea’s per capita CABG rate remains among the lowest worldwide.In contrast, more than 60% of procedures were performed off-pump—the highest rate worldwide. Over time, the average patient age and prevalence of diabetes increased, whereas in-hospital mortality showed a modest decline. Compared with other countries, the Republic of Korea demonstrated a uniquely low procedural volume and a strong preference for off-pump CABG. This nationwide analysis highlights Korea’s distinctive CABG practice patterns and provides valuable insights for optimizing future clinical and policy decisions in cardiac surgical care.
9.Establishing an Active Vaccine Safety Surveillance System Using Large Scale Databases in Korea: Lessons and Scalable Insights for Global Application
Jin Gu YOON ; Eliel NHAM ; Yu Jung CHOI ; Min Joo CHOI ; Won Suk CHOI ; Young Kyung YOON ; Yu Bin SEO ; Hakjun HYUN ; Jung Yeon HEO ; Jin-Soo LEE ; Chung-Jong KIM ; Ji Yun NOH ; Joon Young SONG ; Hee Jin CHEONG
Journal of Korean Medical Science 2026;41(1):e47-
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.
10.Remission of diabetes with glutamic acid decarboxylase antibody positivity that developed after the administration of olanzapine: a case report
Kyuho KIM ; Soo Hyun SEO ; Yun Ji HONG ; Woojae MYUNG ; Bomi KIM ; Chang Ho AHN ; Sung Hee CHOI ; Hak Chul JANG ; Tae Jung OH
Precision and Future Medicine 2026;10(1):51-56
Olanzapine is a second-generation antipsychotic drug associated with the development of type 2 diabetes. However, the development and remission of diabetes with glutamic acid decarboxylase (GAD) antibody (Ab) positivity related to olanzapine treatment have not been reported. Here, we present the case of a 33-year-old man taking olanzapine who was diagnosed with diabetes with GAD Ab positivity complicated by diabetic ketoacidosis (DKA). After discontinuation of the drug and tight glycemic control, his diabetes remitted, and the GAD Ab became negative spontaneously after 18 months. The classification of diabetes is challenging because of overlapping autoimmune and metabolic features. Olanzapine may have contributed to pancreatic β-cell apoptosis, which could potentially trigger autoimmunity and the development of type 1 diabetes-like features (DKA as the initial presentation, a low C-peptide level, and GAD Ab positivity). The rapid amelioration of hyperglycemia and weight reduction may be responsible for the remission of diabetes after the discontinuation of olanzapine.

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