1.Prevalence of Hearing Loss among Primary School Students in Ulaanbaatar, Mongolia
Uyanga D ; Dorjpagma E ; Batzorig B ; Byambasuren L ; Chimedsuren O ; Enkh-Oyun Ts
Mongolian Medical Sciences 2026;215(1):3-8
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.
2.Prevalence of Hearing Loss Among Adults in Ulaanbaatar Assessed by Tablet-Based Hearing Screening
Baigalmaa O ; Byambasuren L ; Junghwa B ; Batzorig B
Mongolian Medical Sciences 2026;215(1):9-19
Introduction:
Hearing loss adversely impacts communication, cognitive function, and quality of life, yet
early detection among adults remains inadequate. Despite the availability of portable, cost
effective tablet-based audiometric screening tools, national-level prevalence data on adult
hearing loss in Mongolia are scarce, and no large-scale screening studies in primary health
care settings have been conducted to date.
Goal:
This study aimed to determine the prevalence of screen-detected hearing loss among adults
in Ulaanbaatar, evaluate its association with age and test frequency, and identify associated
factors.
Material and Methods:
A cross-sectional study was conducted at primary health care clinics across nine districts
of Ulaanbaatar (2024–2025), enrolling 2,335 adults (≥18 years). Hearing screening was
performed using the MAICO easyTone device with DD65 v2A headphones at 500–6000 Hz
(30 dB HL at 500 Hz; 20 dB HL at remaining frequencies), with ambient noise monitored per
ANSI S3.1-2008. Each ear was classified as Pass or Refer at each frequency. Outcomes
included screen-detected hearing loss (SD-HL), speech-frequency hearing loss (SD
SFHL, 500–2000 Hz), and high-frequency hearing loss (SD-HFHL, 4000–6000 Hz), each
categorized as bilateral or unilateral. Associated factors were assessed by univariable and
multivariable logistic regression.
Results:
SD-HL was identified in 37.2% of participants (bilateral: 31.5%; unilateral: 5.7%), SD-SFHL
in 30.6%, and SD-HFHL in 36.3%. Prevalence increased markedly with age, from 29.9%
(40–49 years) to 96.6% (≥70 years) (p<0.001). On multivariable logistic regression, male
sex was inversely associated with a positive screening result (OR=0.65, 95% CI: 0.42–0.99,
p=0.049).
Conclusion
The findings of this study confirm that the MAICO easyTone tablet-based
hearing screening device is a feasible and appropriate tool for the early detection of hearing
loss among adults in routine primary health care settings in Ulaanbaatar. The high prevalence
of screening-detected hearing loss underscores the urgent need to establish adult hearing
screening programs in Mongolia. Future studies should include standard audiometric
confirmation in participants with positive screening results to determine the diagnostic validity
of this hearing screening approach.
3.Results of the surveillance study of school lunch meals and drinking water in general education schools
Byambasuren B ; ; Ser-Od Kh ; Nandin-Erdene O ; Gantuya D
Mongolian Journal of Health Sciences 2026;91(1):54-57
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.
4.Prevalence of Hearing Loss among Middle and High School Students in General Education Schools of Ulaanbaatar, Mongolia
Uyanga D ; ; Batzorig B ; Enkh-Oyun Ts ; Chimedsuren O ; Byambasuren L
Mongolian Journal of Health Sciences 2026;91(1):145-149
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.
5.Development of Mongolian Bisyllabic Word Lists for Speech Audiometric Testing
Baigalmaa O ; Urtnasan D ; Oyunchimeg D ; Junghwa Bahng ; Byambasuren L ; Batzorig B
Mongolian Journal of Health Sciences 2026;91(1):150-156
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.
6.Prevalence of diabetes mellitus and stroke subtypes among patients with ischemic stroke
Naranchimeg G ; Oyuntugs B ; Damdindorj B ; Byambasuren D
Mongolian Journal of Health Sciences 2026;92(2):97-101
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.
7.First successful whole lung lavage for pulmonary alveolar proteinosis in Mongolia: A Case Report
Amartuvshin G ; ; Altanzul L ; Ichinnorov D ; ; Naidansuren Ts ; Solongo B ; Densenbal D ; ; Tumen-Ulzii G ; ; Allabyergyen M ; Tumurjin G ; Khaliun P ; Tamir L ; Erdenetuya E ; Byambasuren S ; Ankhzaya B ; Ganbold L ; Manaljav Ts ;
Mongolian Journal of Health Sciences 2026;93(3):212-216
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.
8.Technologycal study of preparing tablet formulations from hepaclin-4 prescription
Otgontsetseg B ; Khuslen M ; Byambasuren G ; Tserendolgor B
Mongolian Journal of Health Sciences 2025;88(4):38-41
Background:
As of 2024, digestive system diseases rank fourth among the causes of mortality in Mongolia. Among
these, hepatocellular carcinoma (liver cancer) accounted for 20,501 deaths, leading in total mortality rates. In Traditional
Mongolian Medicine, Scutellaria baicalensis Georgi is used to cool blood heat, clear internal heat, and regulate imbalances; Saussurea amara L. is used for its antibacterial, anti-infective, and anti-inflammatory properties; Carthamus tinctorius L. serves for disinfection, pain relief, fever reduction, and detoxification; and Chiazospermum erectum L. is used to
eliminate toxic heat and febrile conditions. Studies have confirmed that the Hepaclin-4 formulation exhibits antioxidant,
membrane-stabilizing, hepatoprotective, anti-necrotic, detoxifying activities, and reduces the accumulation of harmful
byproducts from excessive peroxidation. Therefore, developing a solid dosage form from the raw herbal materials of
Scutellaria baicalensis Georgi, Saussurea amara L., Carthamus tinctorius L., and Chiazospermum erectum L.in the He
paclin-4 formula forms the basis of our research.
Aim:
To formulate and develop a tablet dosage form based on the compound prescription of Hepaclin-4
Materials and Methods:
The raw materials of Scutellaria baicalensis Georgi, Saussurea amara L., Carthamus tinctorius
L., and Chiazospermum erectum L.were weighed at a 1:1:1:1 ratio and extracted with 40% ethanol at a 1:10 ratio using
the remaceration method. Ethanol was evaporated using a vacuum evaporator to obtain a thick extract, and quality indicators were determined. From the obtained thick extract, granules were prepared using two types of excipients through
the wet granulation method, and their quality characteristics were studied. Based on the most suitable granules, tablet
and capsule dosage forms were prepared and standardized according to the methods outlined in the Mongolian National
Pharmacopoeia.
Results:
The Hepaclin-4 tablets were found to be round, well-formed, smooth, with intact edges, a slight characteristic
odor, no unpleasant taste, and light yellow in color. The friability resistance of the 0.5 g tablet was 99.6±0.08%, hardness
was 1.07±0.12 MPa, weight variation ranged from -2.6% to +3.9%, all within the acceptable 5% limit. The disintegration
time was 4.23±0.05 minutes, and dissolution was 95.4±0.47%, meeting the permissible standards. When flavonoids in the
tablets were detected by Thin Layer Chromatography (TLC), brownish-yellow spots appeared at Rf values identical to
standard quercetin (Rf=0.94) and rutin (Rf=0.48). The total flavonoid content, determined by Spectrophotometric Method
(SPM), was 0.165±0.01%.
Conclusion
Tablets were successfully developed from the thick extract of the Hepaclin-4 herbal compound. Upon eval
uation, the tablets met all the required technical specifications.
9.Study of technology for obtaining granular medicine form from Hepaclin-4 prescription
Baasanpurev L ; Byambasuren G ; Ulambayar B ; Tungalag N ; Altantsetseg A ; Adilbish A ; Enkhsaikhan M ; Batbyamba M ; Tsetsegmaa S ; Tserentsoo B ; Altansukh Ts ; Tserendolgor B
Mongolian Pharmacy and Pharmacology 2024;25(2):38-44
Introduction:
Scutellaria baicalensis Georgi, which is used in traditional medicine, has the ability to
remove blood-drying heat. Chiazospermum erectum Bernh. has the ability to relieve typhoid fever and
poison fever. Carthamus tinctorius L. has antiseptic, analgesic and anti-toxic properties. Saussurea amara
L. has bactericidal, anti-infective, and anti-inflammatory properties. Researchers found that the Hepaclin-4
recipe has antioxidant, membrane-strengthening, liver-protective, necrosis-preventing, detoxification, and
peroxidation product accumulation-reducing properties. Therefore, extracting the granular medicine form
from the concentrated extract containing the Hepaclin-4 formulation is the basis of our research work.
Goal:
To obtain the granular medicine form from the concentrated extract containing ingredients of the
Hepaclin-4 recipe.
Materials and Methods:
The research was carried out with the support of the Institute of Pharmaceutical
Research and the University of Pharmaceutical Sciences. The raw materials for the Hepaclin-4 formula were extracted by remaceration with water, 40% ethanol, and 70% ethanol (1:10 ratio). Six types of granules were extracted from the concentrated extract using several excipients by the wet granulation method, and the pouring weight and flowability were determined.
Results:
The quality index of the concentrated extract of the Hepaclin-4 recipe complies with the standards
outlined in the 11th Pharmacopoeia of the National Pharmacopoeia of Mongolia. In qualitative analysis of
total flavonoid, spots were detected at the same level as standard quercetin (Rf=0.88) and rutin (Rf=0.4),
indicating the presence of flavonoids. According to the results of the above research, lactose was found to
be the suitable filler for extracting granules, and starch at 8% was identified as the appropriate binding agent from the concentrated extract of the Hepaclin-4 formula.
Conclusion
It was found suitable to select 8% lactose as a filler and starch as a binding agent from the concentrated extract of the Hepaclin-4 formula and obtain a granule drug form using the wet granulation
method.
10.Study of exposure and vaccination coverage of the medical students
Yanjindulam B ; Naranzul B ; Ulziisuren B ; Byambasuren S ; Gantsetseg G ; Solongo G ; Narangerel P ; Nyammkhuu D ; Nyamsuren B ; Munkhzul D ; Batchimeg Ch ; Ganchimeg Ch ; Oyunbileg D ; Khosbayar T
Diagnosis 2023;106(3):109-117
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.
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