Background: Globally, the average age at menarche was 16–17 years approximately 100 years ago, whereas it has now decreased to 12–13 years. A cohort study published in 2024 involving 71,341 participants titled “Menarche and Time to Cycle Regularity Among Individuals Born Between 1950 and 2005 in the US” reported a decline in the mean age at menarche from 12.5 years among women born between 1950 and 1969 to 11.9 years among those born between 2000 and 2005. Early menarche has been shown to increase the risk of type 2 diabetes mellitus, metabolic syndrome, breast cancer, insulin resistance, obesity, and cardiovascular diseases. Aim: To assess the association between age at menarche and body mass index in adolescent girls aged 11–19 years in middle and high schools in Ulaanbaatar. Materials and Methods: A cross-sectional study was conducted among 75 adolescent girls aged 11–19 years from General Secondary School No. 42 in Songinokhairkhan District, Ulaanbaatar. Data were collected using a structured questionnaire covering demographics, age at menarche, and potential influencing factors. Body mass index was evaluated using international standard criteria. Result: Among the participants, age at menarche occurred at 12 years in 34.7%, 13 years in 26.7%, 14 years in 16.0% and 15 years in 5.3%. Nutritional status assessment showed that 60 participants (80.6%) had a normal body mass index, 13 (17.3%) were underweight, 1 (1.3%) was overweight and 1 (1.3%) had class I obesity. With respect to residential status, 42 participants (56.0%) resided in private houses, 17 (22.7%) in traditional gers, 15 (20.0%) in apartments and 1 (1.3%) in rented housing. Conclusion An association between body mass index and age at menarche was demonstrated among the adolescent girls included in this study, with higher body mass index associated with an earlier age at menarche.

Background: The World Health Organization (WHO) states that no safe level of lead exposure has been established and compared with adults, children absorb approximately four to five times more lead into their bodies. When blood lead levels reach 3.5 µg/dL, which may lead to decreased intellectual capacity, impaired attention, and learning difficulties, potentially resulting in intellectual disability and behavioral disorders. The nervous system and blood–brain barrier in children and adolescents are not fully developed, making them highly susceptible to the neurotoxic effects of lead. Lead disrupts several neurotransmitter systems, including dopaminergic, glutamatergic, and cholinergic pathways. Dysfunction in these systems—particularly alterations in dopaminergic pathways—is closely associated with symptoms of Attention Deficit Hyperactivity Disorder (ADHD). In Mongolia, previous studies have investigated the association between ADHD and lead levels in hair samples among children; however, no studies have examined the relationship between blood lead levels and ADHD. Determining whether blood lead levels influence ADHD in children will provide a scientific basis for preventive measures and the development of additional treatment strategies to reduce clinical symptoms and support clinical practice. Aim: To investigate the association between blood lead levels and ADHD among school children. Materials and Methods: A household-based analytical cross-sectional study was conducted. A total of 306 children aged 6-14 years were randomly selected according to the study inclusion criteria. The Vanderbilt ADHD Diagnostic Questionnaire was administered to parents/guardians and classroom teachers to identify ADHD cases. Blood samples were analyzed to determine blood lead levels using the NIOSH 8005 standard method with Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) in a laboratory accredited under MNS ISO 17025:2018. Additionally, data on lead exposure risk factors were collected using a 15-item questionnaire administered to parents or guardians through the Google Forms platform. Result: Among the participants, 34 children were diagnosed with ADHD. Of these cases, 67.64% were male and 32.35% were female, yielding a male-to-female ratio of approximately 2:1. Boys were 3.6 times more likely to have ADHD than girls (OR=3.675; 95% CI: 2.276-6.210; p<0.0001). Regarding ADHD subtypes, the predominantly inattentive type accounted for 38.2% (n=13), the predominantly hyperactive type for 52.9% (n=18), and the combined type for 8.8% (n=3). When comparing clinical subtypes by sex, the hyperactive type was more common among boys (60.9%, n=14), whereas the inattentive type was more common among girls (45.5%, n=5). The mean blood lead level among all children was 4.8±2.33 µg/dL. Among children with ADHD, the mean level was 6.16±2.47 µg/dL, while among children without ADHD it was 4.75±2.31 µg/dL, indicating a statistically significant difference between the groups. In examining factors influencing the development of ADHD in relation to children’s morbidity status, repeated illnesses such as anemia, rickets, malnutrition, and recurrent acute febrile diseases were identified as statistically significant risk factors (p=0.012). In contrast, acute conditions of short duration were not found to be significant risk factors. Conclusion 1. Among the children included in the study, 34 (11.1%) were diagnosed with ADHD, and the prevalence was higher in boys than in girls. 2. Blood lead levels showed a statistically significant association with Attention Deficit Hyperactivity Disorder in children.

Background: Biotinidase deficiency is an autosomal recessive disorder of biotin metabolism that can be effectively managed when detected early through newborn screening. Biotinidase activity is influenced by neonatal and preanalytical factors, which may affect the interpretation of screening results. Following the introduction of biotinidase deficiency screening in Mongolia in 2025–2026, population-specific data are needed to support accurate screening interpretation. Aim: To determine the distribution and percentile values of biotinidase activity in Mongolian newborns and evaluate associated neonatal and preanalytical factors. Materials and Methods: This analytical cross-sectional study included 6,764 newborns from 12 healthcare facilities in Mongolia between August 2025 and May 2026. After excluding initial screen-positive samples and those with transport times exceeding 30 days, 6,258 newborns were included in the primary analysis. Biotinidase activity was measured in dried blood spots using the Neonatal Biotinidase 3018-0010 kit and VICTOR2D analyzer. Percentile curves by gestational age and birth weight were smoothed using LOWESS. Group differences and associations were assessed using Welch ANOVA and Pearson correlation, respectively. Result: Among 6,258 newborns, mean biotinidase activity was 133.3±32.6 U, with a median of 130.2 U and a P2.5-P97.5 interval of 78.4-206.6 U. Median activity tended to increase with gestational age and birth weight, while the smoothed percentile curves remained above the 58.5 U screening cutoff. Mean activity increased from 124.4±34.1 U in samples collected before 24 hours to 149.9±44.5 U in those collected after 96 hours (p<0.001). Activity showed weak positive correlations with gestational age (r=0.042, p=0.001), birth weight (r=0.114, p<0.001), and body length (r=0.102, p<0.001), but negative correlations with time from sample collection to laboratory receipt (r=−0.327, p<0.001) and from laboratory receipt to testing (r=−0.154, p<0.001). Conclusion Population-specific percentile values for biotinidase activity were established in a large sample of Mongolian newborns. The findings provide baseline data for interpreting biotinidase activity and highlight the importance of standardized sample collection, transport, and testing.

Background: Herbal teas are rich in bioactive compounds with antioxidant, anti-inflammatory, and hepatobiliary supportive properties. Despite their long-standing use in Mongolian traditional medicine for liver and gallbladder health, comprehensive scientific data regarding the specific chemical composition and antioxidant activities of these polyherbal formulations remain limited. Aim: To evaluate the bioactive compound content and antioxidant activity of a polyherbal tea formulation for supporting liver and gallbladder function, with a focus on the influence of solvent concentration. Materials and Methods: The study utilized a polyherbal tea consisting of five plant species: Achillea asiatica Serg., Thalictrum foetidum L., Zygophyllum potaninii Maxim., Tanacetum vulgare L., and Rheum undulatum L. Samples were extracted using 30% and 70% ethanol. Preliminary phytochemical screening was performed using thin-layer chromatography (TLC). Total phenolic content (TPC) was determined using the Folin-Ciocalteu method, and total flavonoid content (TFC) was measured via the AlCl3 colorimetric assay. Antioxidant capacity was assessed through DPPH, ABTS+ and FRAP assays. Results: Phytochemical screening identified flavonoid derivatives, glycosides, and terpenoids in both extracts, while alkaloids were not detected. Quantitative analysis showed that the 70% ethanolic extract contained significantly higher levels of total phenolics (5.518±0.24%) and total flavonoids (1.513±0.023) compared to the 30% extract (p < 0.05). The 70% extract also demonstrated superior antioxidant potency, with lower (IC50) values for DPPH (55.37 µg/mL) and ABTS (86.08 µg/mL). Additionally, the FRAP assay confirmed the 70% extract had substantially higher reducing power (1440.84 µM Fe²⁺/L). Conclusions 1. Phytochemical analysis confirmed that the polyherbal tea is primarily composed of flavonoid derivatives, glycosides, and terpenoids. The total phenolic and flavonoid contents in the 70% ethanolic extract were significantly higher (p < 0.05) than those in the 30% extract. 2. The free radical scavenging activity evaluated by DPPH (IC50) 55.37 µg/mL) and ABTS (IC50) 86.08 µg/mL) assays indicated that the 70% ethanolic extract possesses markedly stronger antioxidant activity compared to the 30% extract. 3. The iron ion reducing power (FRAP: 1440.84 µM/L) showed a concentration-dependent linear relationship. The positive correlation between polyphenol content and antioxidant activity confirms that this herbal formulation has a scientific basis for its traditional use in supporting liver and gallbladder function.

Background: Early and accurate differentiation of benign and malignant breast nodules is crucial for determining appropriate therapeutic strategies. Recently, artificial intelligence (AI)-based diagnostic systems have been increasingly utilized to enhance the diagnostic performance of ultrasound imaging. Aim: To evaluate the diagnostic value of artificial intelligence-based ultrasound (AI-US) in differentiating benign and malignant breast nodules and to compare its performance with conventional ultrasound (US). Materials and Methods: This retrospective study included 101 patients with 103 breast nodules (58 malignant, 45 benign) confirmed by histopathological analysis (biopsy or surgery). Diagnostic performance was evaluated across three groups: 1) Conventional ultrasound (US), 2) AI system (AI group), and 3) Combined US and AI system (US+AI group). Sensitivity (SE), specificity (SP), accuracy (ACC), positive predictive value (PPV), negative predictive value (NPV), and the area under the ROC curve (AUC) were calculated and compared. Results: Of the 103 nodules, 56.3% were malignant and 43.7% were benign. The AI group demonstrated higher diagnostic metrics than the US group—SE (82.76%), SP (80.00%), ACC (81.55%), and AUC (0.814)—though the difference was not statistically significant (p>0.05). However, the combined US+AI group showed significant improvement, reaching an SE of 87.93%, SP of 86.67%, ACC of 87.38%, and an AUC of 0.874. These results were statistically superior to the conventional US group (p<0.05). Conclusion The AI-based ultrasound diagnostic system significantly improves the accuracy of differentiating breast nodules. This technology serves as a reliable decision-support tool, particularly for reducing diagnostic errors among less experienced physicians and minimizing unnecessary invasive biopsies.

Background: The human head is an integrated biological structure composed of the brain, cranial bones, facial structures, neuromuscular systems, and sensory organs, all interconnected through coordinated signaling. The relationship between brain development, function, and craniofacial growth is most evident after birth, during which the head increases approximately fourfold in size before adulthood. Brain morphology and volume are associated not only with neurological disorders but also with cognitive and behavioral characteristics. For example, children with holoprosencephaly often present with varying degrees of facial anomalies, while studies have shown that adolescents with malocclusion exhibit higher levels of anxiety, depression, and psychological stress. With the increasing availability of magnetic resonance imaging (MRI), it has become an essential diagnostic tool in clinical practice. MRI is particularly advantageous in pediatric populations due to the absence of ionizing radiation and its superior soft tissue contrast. Recent advances in image processing techniques have enabled comprehensive analysis of both brain structures and craniofacial morphology from a single MRI dataset, forming the basis of this study. Aim: To investigate the relationship between brain tissue volumes and maxillary hypoplasia using MRI-based voxelbased morphometry in children with neurological conditions. Materials and Methods: This study was conducted at the School of Biomedicine, Mongolian National University of Medical Sciences, in collaboration with Chifeng University, as part of the project titled “Investigation of the relationship between craniofacial anomalies and brain disorders using MRI”, funded by the Ministry of Education and Science. Voxel-based morphometry (VBM) analysis was performed on brain MRI scans of children aged 9–11 years. Results: Among the 25 children included in the study, 17 (68%) were male. The youngest average age was observed in the maxillary hypoplasia group (8.4±0.95 years). The signal-to-noise ratio (SNR) of MRI was lowest in the non-temporal epilepsy group (41.1±1.35) and higher in the maxillary hypoplasia group (49.6±8.22). Both epilepsy and maxillary hypoplasia groups demonstrated physiological asymmetry of the cerebral hemispheres, with left parietal lobe dominance (−0.1% and −0.3 cm, respectively). Right frontal lobe dominance (+1.1%) was observed only in the epilepsy group. Conclusion Children aged 9–11 years with maxillary hypoplasia showed a reduction in both gray and white matter volumes of the brain. These findings highlight the importance of early diagnosis of neurodevelopmental disorders affecting odontogenesis and emphasize the need for a multidisciplinary team-based management approach.

Background: Cancer incidence and mortality are steadily increasing both globally and in Mongolia. As these rates rise, traditional Mongolian medicine has long utilized herbal formulas for the treatment of gastric and esophageal cancers and precancerous conditions. One such formulation—Hot Natured 3 Herbs (HN3H)—comprises three species from the Ranunculaceae family: Atragene sibirica L., Ranunculus repens L., and Pulsatilla bungeana L.. However, scientific validation of its anti-tumor effects is essential. This study aimed to investigate the effect of HN3H in a tumor-induced animal model. Aim: To identify the biologically active compounds of HN3H and evaluate their effect in an experimentally induced tumor model in animals. Materials and Methods: The three herbs comprising HN3H—Atragene sibirica L., Ranunculus repens L., and Pulsatilla bungeana L.—were collected during their flowering stage (May–June) in Khishig-Undur, Bulgan province, and dried according to official procedures. Extraction was carried out by maceration in 96% ethanol at a 1:10 ratio. The concentrated extract was suspended in water (1:1) and successively fractionated with dichloromethane, ethyl acetate, butanol, chloroform, and n-hexane. The study was approved by the Research Ethics Committee of the Mongolian National University of Medical Sciences (Protocol №2020/03-04). A colorectal cancer model was established by subcutaneous injection of MC-38 cells (Kerafast, USA) into C57BL/6 mice. Immunohistochemistry was performed using CK20, CDX2, Ki67, and p53 antibodies at 1:100 and 1:200 dilutions. Results: The ethanol extract of HN3H contained 2.98±0.04% total phenolics and 2.16±0.05% total flavonoids. Body weight and tumor volume were measured daily with three repetitions. All groups showed a time-dependent increase in body weight. Mice in groups 1A and 1B received ethanol extract at 50 and 100 mg/kg doses; groups 2A and 2B received dichloromethane extract at the same doses. The negative control group was administered 0.5 mg/kg PBS orally, while the positive control group received intraperitoneal injections of 5-fluorouracil (5FU) at 10 mg/kg twice a week. Tumor growth increased in a time-dependent manner across groups. Compared to the negative control, tumor volumes in four treatment groups showed statistically significant reduction (p˂0.05), while no significant difference was observed when compared to the positive control (p=0.08). Histological analysis revealed necrosis in all groups, with variation in extent. Conclusion The ethanol extract of HN3H exhibited moderate levels of phenolic compounds and a high concentration of flavonoids. HN3H extract inhibited tumor progression and activated lymphocyte-predominant inflammation in tumor tissues, indicating potential anti-tumor activity (p˂0.05).

: We report a case of a 1-year-6-month old baby presenting with classic clinical of Prader-Willi syndrome, a rare congenital disorder. Early identification and multidisciplinary management are critical to improving outcomes. Case presentation: Patient U is a 1.5-year old male. Due to his inability to breastfeed for the first day after birth, diagnostic tests were initiated. He was dependent on tube feeding for over two months. At 9 months, the child was able to hold their head up and began sitting independently around 11 months. His eyes are slightly slanted, the bridge of his nose is narrow, the upper lip is thin, and the corners of his mouth are downturned.The skin soft texture. Muscle tone is noted to be weak. The size of the arms and feet is small. Additionally, the neck is of short stature. Cytogenetic Analysis: November 2023. The analysis identified a microdeletion in the 15q11-q13 chromosomal region. He was discharged from the hospital upon demonstrating the ability to suck effectively, achieving consistent weight gain, and having his sucking and swallowing activities adequately controlled. Discussion and Conclusion Prader-Willi syndrome is a genetic disorder resulting from the non-expression of a gene located on chromosome 15 at the 15q11.2–q13 region. The prevalence of corresponding to an approximate global total of 350,000 to 400,000 cases. The sex ratio is equivalent at 1:1. In the initial year of life (0–1 year), affected infants commonly present with muscle weakness, difficulties in feeding, reduced sucking capabilities, absence of crying or vomiting, diminished motor activity, poor muscle strength, and low weight. For individuals aged 1 to 10 years, symptoms encompass increased appetite, obesity, delays in speech and psychomotor development, a long facial structure, narrow forehead, downturned mouth and eyes, small hands and feet, along with other distinctive facial features. In adolescence and adulthood, prevalent symptoms may include behavioral changes, irritability, uncontrolled eating habits, diabetes, and depression. From infancy onward, holistic care may include nutritional interventions (such as tube feeding and specialized diets), strategies for heat retention, enhancement of sucking abilities. Cardiovascular and respiratory monitoring, weight management, physical activity support, health education for families and caregivers, growth hormone therapy, psychological counseling, sex hormone replacement therapy, and assistance with movement, psychomotor skills, cognitive and intellectual development, alongside speech therapy. Timely diagnosis, integrated multidisciplinary care, and proactive family involvement have the potential to markedly enhance the quality of life for affected individuals.

: We report a case of a 1-day-old neonate presenting with classic clinical and radiologic features of sacral agenesis, a rare congenital disorder. Early identification and multidisciplinary management are critical to improving outcomes. Case Presentation : A full-term, 1-day-old infant was examined for multiple congenital deformities. Physical f indings included a large head, round eyes, and a shallow chest. The lower limbs were short, internally rotated, and stiff, with minimal mobility at the hip and knee joints. External rotation of the hips was not possible, and both feet were turned inward.
A CT scan of the lumbar spine (without contrast) revealed normal cervical and thoracic vertebrae. However, one thoracic vertebra showed an unclear structure. At the spine’s end, a 2.0 × 1.5 × 1.1 cm spindle shaped mass with a density of +14 to +27 HU was seen under the skin on the right. The pelvis appeared underdeveloped, with an incomplete oblique fracture of the upper right midshaft femur. Upright radiography confirmed underdeveloped pelvic bones. The medial malleolus and tibia appeared symmetrical bilaterally. Epidemiology: Sacral agenesis (caudal regression syndrome) is a rare congenital condition with an estimated incidence of 1 in 100,000 live births. It is more common in infants born to mothers with pregestational diabetes, although it can occur sporadically. Both genetic and environmental factors may contribute.[11] Discussion : Sacral agenesis results from abnormal development of the caudal mesoderm during early embryogenesis, leading to partial or complete absence of the sacrum and sometimes lumbar spine. The severity ranges from isolated sacral agenesis to complete lumbosacral agenesis with associated genitourinary, gastrointestinal, and limb deformities. [8-10].
The current case presented with classic signs: bilateral lower limb deformities, limited joint mobility, underdeveloped pelvis, and a spinal abnormality. The presence of a spindle-shaped subcutaneous mass may represent a lipoma or associated spinal dysraphism. The incomplete femoral fracture may be due to birth trauma in the context of fragile bones or abnormal limb positioning.
Early imaging helps confirm the diagnosis and evaluate associated anomalies. Management typically involves orthopedic, neurologic, and urologic interventions. Long-term care focuses on mobility, continence, and developmental support. [13,14]. Conclusion: This case emphasizes the importance of recognizing sacral agenesis at birth through clinical examination and radiological imaging. Although rare, early diagnosis is vital for implementing supportive care and planning multidisciplinary interventions. Close follow-up is essential to monitor motor development and prevent complications. Ethical Considerations (EHT) : Ethical approval was obtained from the institutional review board. Parental consent was secured for the publication of clinical data and images. All procedures followed ethical standards of clinical care and the Helsinki Declaration. Confidentiality of patient information has been maintained throughout the report. No invasive procedures beyond standard diagnostics were performed. Acknowledgments The authors thank the Neonatology and Radiology Departments of Regional Diagnostic Center of Umnugovi Province for their contributions to the diagnosis and imaging. We also appreciate the cooperation of the child’s family and the medical ethics committee for guidance and approval. Special acknowledgment to the Division of Pediatric Neonatologists for their early intervention planning and support.

Background: Hepatitis C virus (HCV) is a blood-borne infectious disease that, if left untreated, can lead to chronic infection, liver cirrhosis, and hepatocellular carcinoma. In Mongolia, the prevalence of HCV is relatively high, posing significant public health concerns. In alignment with the global goal to eliminate hepatitis B and C by 2030, this study aimed to investigate the prevalence, genotype distribution, and associated risk factors of HCV infection among the general population in Arkhangai province, Mongolia. Aim: To determine the prevalence of hepatitis C virus infection among the relatively healthy population of Arkhangai Province and to study its genotypes and risk factors. Materials and Methods: A cross-sectional analytical study was conducted using a two-stage sampling method, enrolling 2,304 individuals aged 0–80 years. Participants completed a structured questionnaire, and blood samples were collected for anti-HCV and HBsAg testing using enzyme-linked immunosorbent assay (ELISA) at the central laboratory of the provincial hospital. Serum from anti-HCV positive individuals was preserved at –80°C and transported to Ulaanbaatar for HCV RNA quantification via real-time polymerase chain reaction (RT-PCR) and genotyping through molecular diagnostics. Statistical analyses were conducted using SPSS version 26.0. Results: A total of 2,304 individuals from the provincial center and 8 soums participated in the study, of whom 57.8% were female. The overall HCV seroprevalence was 12.0%, with chronic HCV infection confirmed in 7.16%. Among patients with chronic HCV, genotype 1b was identified in 98.2% of cases. Risk factor analysis revealed statistically significant associations between HCV infection and undergoing cosmetic procedures, receiving injections in non-medical settings, cupping therapy, and sharing shaving equipment. Conclusion This study HCV seroprevalence of 12.0% among the relatively healthy population in Arkhangai province, with genotype 1b detected in 98.2% of chronic HCV cases. The following risk factors were found to be independently associated with HCV infection: undergoing cosmetic procedures (OR: 2.3), cupping therapy (OR: 1.7), receiving nonmedical injections (OR: 2.4), and sharing shaving tools (OR: 1.5) (p<0.001)