Introduction: Hearing loss is an important public health issue that negatively affects children’s speech, cognitive development, academic performance, and social interaction. Even mild hearing impairment may lead to adverse developmental outcomes. However, data on hearing loss among primary school children in Mongolia remain limited. Goals: To determine the prevalence, type, and severity of hearing loss among primary school students in Ulaanbaatar and to assess associated socio-demographic factors. Material and Method: A school-based cross-sectional study was conducted among 1,254 primary school students. Hearing screening was performed using pure-tone audiometry following a standardized protocol. Students who failed the screening were referred for confirmatory diagnostic audiometry. Hearing loss was classified as mild (21–35 dB), moderate (36–50 dB), and severe (≥50 dB). Socio-demographic data were collected using a structured questionnaire. Statistical analysis data were analyzed using RStudio software. Descriptive statistics were used to summarize participant characteristics. Associations between hearing loss and independent variables were examined using chi-square tests and logistic regression analysis. Variables with p<0.20 in univariate analysis were included in the multivariable logistic regression model. Odds ratios (ORs) with 95% confidence intervals (CIs) were reported, and p<0.05 was considered statistically significant. Ethical considerations: The study protocol was approved by the Institutional Ethics Committee (Approval No. 2024/3 06). Written informed consent was obtained from parents or legal guardians, and assent was obtained from participating students prior to data collection. Results: Of the 1,254 students, 116 (9.2%) required further evaluation, and hearing loss was confirmed in 23 students (1.8%). Most cases were mild in severity. Paternal education level was significantly associated with hearing loss (p=0.028), whereas no significant associations were observed for sex or household income. Conclusion The prevalence of hearing loss among primary school students in Ulaanbaatar was 1.8%, with most cases being mild and unilateral. These findings highlight the importance of implementing regular school-based hearing screening programs and improving parental awareness of children’s hearing health.

Background: Although food-borne infectious diseases occur across all age groups globally, evidence indicates that young children, older adults, and immunocompromised individuals are disproportionately affected due to their increased susceptibility to enteric pathogens. Young children in particular are at higher risk because their immune systems are not yet fully developed and they have lower body mass, which together reduce their ability to resist and recover from food-borne infections. In Mongolia, reported cases of intestinal infectious diseases in 2024 exceeded the ten-year historical average by 504.5 cases, and food- and water-related infections such as hand-foot-and-mouth disease, dysentery, and salmonellosis remain predominant among these conditions. Aim: The objective of this study was to conduct microbiological analyses of school lunches and drinking water provided to general education school students and to evaluate their compliance with relevant national standards. Materials and Methods: A total of 107 school lunch samples and 35 drinking water samples collected from general education schools were included in the study. Microbiological analyses were performed to assess hygiene and safety indicators, including Listeria monocytogenes, Salmonella spp., total coliform count, total viable microbial count (TVC), and intestinal bacteria. Laboratory analyses were conducted at the Microbiology Laboratory of the Food Safety Reference Laboratory under the Standardization and Metrology Authority. Confirmatory identification of microorganisms was performed using the VITEK 2 Compact system. Result: Of the 35 drinking water samples analyzed for 105 parameters, 8.5% (n=3) exceeded the permissible limits for total microbial counts. In the 107 school lunch food samples, a total of 428 microbiological parameters were examined, of which 26.1% (n=28) showed coliform counts above the allowable limits specified in the MNS 6308:2012 standard. Additionally, enterobacteriaceae were detected in 42.9% (n=46) of the food samples. When analyzed by school, 51.5% of the 35 schools (18 schools) had food samples with coliform counts that did not meet the standard requirements, whereas 49.5% (17 schools) showed compliance with the standards. These findings indicate that, on average, one out of every two schools fails to meet the required hygiene practices, proper food production procedures, and microbiological safety standards in meal preparation. Conclusion Microbiological analysis of 107 food samples from 35 general education schools across 428 indicators revealed that 26.1% did not meet the requirements of the MNS 6308:2012 “Microbiological safety and hygiene criteria for food products” standard due to excessive coliform counts. Of the 35 drinking water samples analyzed for 105 indicators, 5.7% (n=2) failed to meet the requirements of the MNS 0900:2018 “Drinking water: Hygiene requirements, quality, and safety assessment” standard with respect to total viable microbial count.

Background: Hearing loss among adolescents remains an important public health concern, as even mild degrees of hearing impairment can adversely affect cognitive development, academic performance, and social interaction. In Mongolia, evidence on the prevalence of hearing loss among school-aged children is limited, providing the rationale for conducting this study. Aim: To determine the prevalence, type, and severity of hearing loss and to assess associated demographic factors among middle and high school students in Ulaanbaatar, Mongolia. Materials and Methods: A school-based cross-sectional study was conducted during 2024–2025 among 1,803 students from 18 general education schools across nine districts of Ulaanbaatar. Hearing screening was performed using pure-tone audiometry according to a standardized protocol, and students who failed the initial screening underwent confirmatory audiometric testing. Hearing loss was classified as mild (21–35 dB), moderate (36–50 dB), or severe (≥50 dB). Demographic information was collected from parents or guardians using a structured questionnaire. Data were analyzed using R software. Associations were assessed using the chi-square (χ²) test, with p<0.05 considered statistically significant. Result: Among the students screened, 7.4% were identified as requiring further evaluation, and hearing loss was confirmed in 2.3%. Parental educational level was significantly associated with hearing loss, while no significant differences were observed by sex. Conclusion The prevalence of hearing loss among middle and high school students in general education schools in Ulaanbaatar was 2.3%, with no significant difference by sex. Most identified cases were mild and unilateral, highlighting the need for regular school-based hearing screening and strengthened parental health education. The association between parental educational level and hearing loss suggests the importance of addressing social determinants, and further studies are warranted to explore additional risk factors such as the use of personal listening devices.

Background: Speech audiometry is a widely used standard diagnostic method in the evaluation of hearing and auditory function. It requires word materials that are developed in the native language of the target population and that reflect its phonetic characteristics. Because the phonetic structure, pronunciation, and familiarity of words directly influence speech recognition, it is essential to use language-specific word lists that are phonetically balanced, uniformly distributed, and psychometrically validated to ensure the accuracy and reliability of testing. Therefore, there is a strong need to develop Mongolian bisyllabic word lists that are balanced in both phonetic and psychometric properties, which forms the basis of this study. Aim: To develop psychometrically balanced Mongolian bisyllabic word lists for use in speech audiometry and to evaluate their suitability for determining the Speech Recognition Threshold (SRT). Materials and Methods: Fifty-five commonly used and phonetically balanced Mongolian bisyllabic words were selected and recorded by a professional female speaker. The recordings were presented to 50 normal-hearing participants aged 18–29 years at ten intensity levels ranging from –4 to 14 dB HL in 2-dB steps. Based on participants’ responses, the 50% SRT and the 20–80% slope of the psychometric function for each word were calculated using logistic regression. Chi-square and one-way ANOVA analyses were performed to examine the equivalence between lists. On the basis of these results, two psychometrically balanced half-lists, each containing 25 words, were constructed, and digital level adjustments were applied to ensure uniform intensity. Result: The slopes of the psychometric functions for the two half-lists ranged from 11.2 to 11.6 %/dB. Chi-square and one-way ANOVA analyses showed no statistically significant differences between the two lists in terms of the 50% SRT and psychometric slope derived from logistic regression [χ²(24, N=50) = 2.21, p = 0.99; F(1,48) = 0.00895, p = 0.925]. The mean pure-tone average (PTA) threshold of the 50 normal-hearing participants was 2.23 dB HL with a standard deviation of 4.4 dB. The difference between PTA and SRT was less than 10 dB HL for all participants, which is within the clinically acceptable range. Conclusion The developed Mongolian bisyllabic word lists, consisting of two 25-word sets, are suitable for determining the Speech Recognition Threshold and can be reliably applied in clinical speech audiometry practice.

Background: Stroke is the second leading cause of death and disability worldwide. According to the World Health Organization report (2018), Mongolia has one of the highest stroke rates in the Western Pacific region and ranks second globally in stroke mortality and first in stroke-related disability. However, studies investigating the prevalence of diabetes mellitus (DM) among stroke patients in Mongolia remain limited. Aim: To determine the prevalence of diabetes mellitus among patients hospitalized due to ischemic stroke and to analyse the distribution of stroke subtypes. Materials and Methods: This retrospective study included patients with ischemic stroke who were admitted to the First and Third Central Hospitals of Mongolia within 24 hours after stroke symptom onset between 2024 and 2025. Data from 292 patients were analyzed. Demographic characteristics, stroke severity, time intervals, and laboratory findings were collected and compared between patients with and without diabetes mellitus. Result: The mean age of the study population was 61.9±12.9 years, and the majority of participants were male. Diabetes mellitus was present in 25% of the patients. The median duration of diabetes was 16 years (range 0–23 years), and the mean HbA1c level was 8.81±2.46%. There were no significant differences between diabetic and non-diabetic patients in terms of age, sex distribution, stroke severity, length of hospital stay, or in-hospital mortality. However, body mass index and glycemic parameters were significantly higher in patients with diabetes (p<0.001). According to the TOAST classification, small vessel disease was the most common stroke subtype, accounting for 57.3% of cases in patients with diabetes and 44.2% in patients without diabetes. Conclusion 1. Diabetes mellitus was present in one out of every four patients hospitalized with ischemic stroke. 2. Atherosclerotic stroke was six times more frequent in patients with diabetes compared with those without diabetes, highlighting the importance of early detection and management of diabetes in stroke prevention.

Background: Pulmonary alveolar proteinosis (PAP) is a rare lung disorder characterized by the accumulation of surfactant within the alveoli, leading to impaired gas exchange and respiratory insufficiency. Although the disease is uncommon, it significantly affects patients’ quality of life and requires specific diagnostic and therapeutic approaches. Whole lung lavage (WLL) is considered the standard treatment; however, it has not been widely implemented in Mongolia. We report the first successful case of WLL performed for PAP in Mongolia. Case Presentation: A 56-year-old male presented with dyspnea. Chest computed tomography demonstrated a bilateral “crazy paving” pattern. Bronchoalveolar lavage fluid was positive for periodic acid–Schiff (PAS) staining, and anti–GM-CSF antibodies were detected, confirming the diagnosis of PAP. WLL was performed under general anesthesia using a double-lumen endotracheal tube with bronchoscopic guidance. One lung was ventilated with 100% oxygen while the contralateral lung was sequentially lavaged with 800–1000 mL of warm (37°C) saline per cycle until the effluent became clear. A total of approximately 20 liters of saline was used. Result: The procedure was completed successfully without complications. Following treatment, the patient showed marked clinical improvement with reduced dyspnea and increased exercise tolerance. Oxygen saturation improved from 88% to 93%, and spirometric parameters (FVC, FEV₁) demonstrated improvement. Chest imaging revealed a reduction in pulmonary opacities. Conclusion This case demonstrates the successful implementation of whole lung lavage (WLL) in Mongolia and highlights its importance in improving the diagnostic and therapeutic capacity for rare pulmonary diseases such as pulmonary alveolar proteinosis. The procedure resulted in significant improvement in clinical, functional, and radiological parameters, consistent with findings from international studies. Early diagnosis of PAP and the adoption of standardized protocols in accordance with international guidelines are essential to optimize treatment outcomes and enhance patients’ quality of life.

Background: To prevent and combat the spread of the COVID-19 pandemic, the Government of Mongolia has implemented measures such as movement and time restrictions, social distancing and isolation, closure of schools, kindergartens and public places, immunization, and others. It has caused adverse consequences for people, social relations, and the economy, causing health, social, economic, and humanitarian crises. Not only does this situation, medical students, as frontline healthcare workers, are more susceptible to virus infection. Vaccines against COVID-19 have been researched quickly due to the pandemic and are being used under emergency use authorization. In our country the approach of mixing vaccine doses from different manufacturers was used (fractional doses). Therefore, there is no study on the exposure of medical students to the COVID-19 infection and the adverse effects after receiving a dose of a heterologous vaccine. Objective: To study the exposure to the COVID-19 infection and vaccination status of medical students. Methods: The survey was conducted from November 2023 to December 2023 using a cross-sectional study design, and 170 students who study at ASUSU and live in the dormitory were included. Results: A total of 170 students participated in the study. 55.9% (n=95) of them were in the first year, 22.4% (n=38) were in the second year, 10% (n=17) were in the third year, 7.6% (n=13) were in the fourth year, 2.4% (n=4) were from the 5th year and 1.8% (n=3) were from the 6th year students. 88.2% (n=150) of students were female and 11.8% (n=20) were male. In this study, 37.1% of the students were infected by COVID-19 infection previously. Among them, 50% of the students were infected from family members, 16.7% from the school environment, and 15.2% did not know about the source of infection. 76.2% of the respondents were diagnosed with COVID-19 in a medical institution, and forty-one students answered that they were treated at the hospital. 83% of the cases were treated at home and were cured within 14 days. In contrast, 93.8% of the hospitalized students were treated within four months to 1 year. The current study demonstrates neurological, respiratory, sensory, cardiovascular, psychiatric, digestive, and dermatological symptoms were in 37.6%, 24.1%, 27.6%, 17.6%, 11.8%, 11.2%, and 10% of the students who participated in the study, respectively. For a year or more, symptoms of all organ systems were present, but neurological symptoms appeared to be the highest. 55.9% (n=115) of the enrolled students received 3 or 4 doses of the vaccine, 3.5% (n=6) did not receive the vaccine. In total, 35% (n=60) of the enrolled students experienced side effects and 65% (n=106) had no side effects. Conclusion In this study, 37.1% of the students were infected by COVID-19 infection previously. According to the current study, symptoms related to the nervous system was the most prevalent and 55.9% (n=115) of the enrolled students received 3 or 4 doses of the vaccine. In total, 35% (n=60) of the enrolled students experienced side effects.

Introduction: Khuumii (throat singing) is a unique form of art derived from the nomadic population of Central Asia, producing two or more “simultaneous” sounds and melodies through the organ of speech. Material and Methods: The aim of the study is to identify the anatomical structures involved in the formation of khuumii and the features and patterns of their functions and compare each type of khuumii as performed by Mongolian people. A total of 60 participants aged 18-60 years (54 men and 6 women) were selected by non-random sampling method using cross-sectional study. Statistical analysis was performed using SPSS 23 software using questionnaires, X-ray, endoscopy, sound research method, and general blood tests. Results: 90.7% of the khuumii singers were male and 9.3% were female. The average height of the participants was 172.91±0.93 cm (arithmetic mean and mean error), average body weight was 77.53±2.46 kg, and body mass index was 25.93±5.31 respectively. Heart rate was 92.19±20.71 per minute prior to khuumii while 133.19±19.09 after performing khuumii and 85.81-98.56 at 95% confidence interval. In terms of ethnicity (ethnographically), the Khalkh were the largest ethnic group (72.1%), followed by Bayad, Buryatia, Darkhad, Torguud, and Oirat (2.3%), respectively. 60.5% of the participants were professional khuumii singers who graduated from relevant universities and colleges. The process of Khuumii was recorded by X-ray examination, and laryngeal endoscopy evaluated the movement of true and false vocal chords, interstitial volume, movements of epiglottis and arytenoid cartilage, and mucosa. Khuumii increases the workload of the cardiovascular system by 70-80%. Furthermore, the sound frequency is 2-4 times higher than that of normal speech, and sound volume is 0.5-1 times higher. 95.3% of throat singers did not have a sore throat, 88.4% did not experience heavy breathing, and 74.1% had no hoarseness. During the formation of khuumii sound, thoracic cavity, diaphragm, and lungs regulate the intensity of the air reaching the vocal folds, exert pressure on the airways and vibrate the sound waves through air flows passing through the larynx and vocal folds. Mouth-nose cavity as well as pharynx are responsible for echoing the sound. Conclusion It is appropriate to divide khuumii into two main types according to structural and functional changes in the organs involved; shakhaa and kharkhiraa. Khuumii, the “Human music” originating from the people of Altai Khangai basin by imitating the sounds of nature with their own voice in ancient times, spread all over the world from Mongolia and it is proposed to classify khuumii into two main types of shakhaa and kharkhiraa in terms of structural involvement and functionality.

Background: Data from yearly statistical reports on morbidity and mortality in Mongolia show that young adults account for approximately 20-26% of all stroke patients as opposed to 10-13% in Western countries. Objectives: The aim of this study was to compare characteristics of ischemic stroke between young (20-49 years) and old (50-79 years) patients undergoing investigations and treatment according to one common protocol in a tertiary hospital. Material and Methods: This hospital based prospective study included 110 young and 130 old patients with acute ischemic stroke. Data regarding the etiology of the stroke, diagnostic neuroimaging test results and degree of functional improvement of patients were examined during their observation. Results: The frequency of ischemic stroke at the age of 20-49 years grows from 9.6% to 24.2% and is predominant in the male sex (17.1%), which indicates a young stroke in mongolians is not uncommon. Young adults with ischemic stroke frequently bear both traditional and specific vascular risk factorsthan elderly people (p<0.05). The most common TOAST subtype in the young and old groups was undetermined (26.4% vs.12.3%; p=0.004), other determined cause (22.7% vs. 6.9%; p<0.001), and cardioembolism (20.0% vs. 22.3%) followed by Large-artery atherosclerosis (17.3% vs. 26.2%) and small vessel occlusion (15.6% vs. 33.8%; p<0.001). Partial anterior circulation infarcts were more common among young patients (p<0.001), than in posterior circulation infarcts. Silent brain infarcts and leukoaraiosis are not uncommon brain imaging findings (<0.05) in hypertensive and migraineur patients and should not be overlooked due to their potential prognostic relevance. Outcomes in young adults with hemispheric ischemic stroke can safely be improved with Low- molecular-weight-heparin therapy (OR 1.58; 95% CI, 0.99-2.51; p=0.001).
There were large differences between two groups concerning the 6-month outcome which showed beneficial effect for young stroke patients (mRS:89.1% vs. 66.9%, p=0.002; BI: 84.2% vs.73.1%). Conclusion There are significant differences between young and old patients with ischemic stroke regarding to risk factors, etiological subtypes and improvement of functional deficits associated with the stroke. However, severity of stroke on admittance is similar but six weeks outcome is different among young and old patients with relatively rapid improvement of functional deficit in young stroke patients than old one (mRS: 89.1% vs. 66.9%, p=0.002; BI: 84.2% vs.73.1%).

Background: According to the report of see in 2016, 90% of adults are using mobile phones and 64% smart phones, and healthcare organizations are beginning to explore the opportunities in which mobile phones can improve and streamline care. In this study involves the risk of pathogenic virus and bacteria of mobile phones used by healthcare workers. That detected common adenovirus and influenza virus as well as streptococci and staphylococci. Material: In this study was carried out in bacteriology laboratory at the "School of Biomedicine MNUMS". The research collected from the random methods and Mongolian National University of Medical Science‟s 80 students are participated and take a test sample that detected bacteria, them using smart phones. After all students from gave them a survey about usages and clean of smart phones. Results: The results revealed 66% of pathogenic bacterial contamination. Our survey was detected in 33 (63,5%) S.aureus, S.pneumoniae-5 (9.4%) E.coli 2 (3.8%) Bacillus, spp-4 (7.6%) Enterococcus-6 (11.5%) Acinetobacter-2 (3.8%). HOW TO CLEAN YOUR CELL PHONE? asked to total participate in this study. They said that they cleaned up their cell phones in 55.9% once every 3-7days, 11.9% once every 10-14 days and 32.2% once a month and more than. Conclution Are participated in this survey sample have been contaminated bacteria 66%. In total samples have been detected 63,5% in S.aureus and 11.5% in Enterococcus. So students‟ mobile phones may become rick high reservoir of microorganism for infections.