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.

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.

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: Hemophilia A (HA) and hemophilia B (HB) are monogenic bleeding disorders caused by pathogenic variants in the F8 and F9 genes, respectively, which are located on the X chromosome and result in deficiencies of coagulation factor VIII (FVIII) and factor IX (FIX). The diseases predominantly affect males, while females are usually asymptomatic heterozygous carriers. Identification of female carriers among relatives of affected males is important for preventing bleeding complications associated with surgery and childbirth. Aim: The main aim of this study was to detect carrier and non-carrier women and compare some phenotypes. Materials and Methods: The study included 50 female relatives of 32 male patients diagnosed with hemophilia A and 13 female relatives of 8 male patients diagnosed with hemophilia B, giving a total of 63 female relatives. Molecular genetic testing was performed to identify the pathogenic variants previously detected in the probands and to determine the carrier status of female relatives. Among them, 33 confirmed carriers and 18 non-carriers completed a 28-item questionnaire comprising three sections to assess bleeding-related symptoms. The questionnaire evaluated easy bruising, duration of menstruation, postpartum bleeding, and bleeding following injuries, surgical procedures, and dental procedures. Questionnaire findings were compared between molecularly confirmed carriers and non-carriers. Continuous variables were compared using the Mann–Whitney U test, while categorical variables were analyzed using Fisher’s exact test in R software. In female relatives of patients with hemophilia A, plasma FVIII activity was also measured. Result: Molecular genetic testing was performed in 52 female relatives. Eleven women were excluded from carrier-status analysis because no pathogenic variant was identified in the F8 or F9 gene of their respective probands. Among 43 female relatives of patients with hemophilia A who underwent carrier testing, 26 (60.4%) were identified as carriers and 17 (39.5%) as non-carriers. Among eight male patients with hemophilia B, pathogenic F9 variants were identified in six; among their seven female relatives, six were confirmed carriers and one was a non-carrier. The mean FVIII activity among heterozygous HA carriers was 58.5±20.6 IU/dL (n=17), which was significantly lower than that of non-carriers (101±28.8 IU/dL; p<0.001). Of the nine bleeding-related symptoms assessed, only easy bruising of the skin was significantly more common among carriers (OR=6.8; p=0.0069). Although prolonged menstrual bleeding and bleeding after childbirth, surgery, or dental procedures were reported among some carriers, no statistically significant differences were observed between carriers and non-carriers. Conclusion Among female relatives of males diagnosed with Hemophilia A or B in Mongolia, 32 (64%) of 50 women were identified as carriers and 18 (36%) as non-carriers. Plasma FVIII activity was significantly lower in HA carriers than in non-carriers (58.5±20.6 IU/dL vs. 101±28.8 IU/dL; p<0.001). Easy bruising was significantly more frequent among carriers (OR=6.8; p=0.0069). These findings support the importance of molecular genetic testing for identifying female carriers and recognizing women who may be at increased risk of bleeding, particularly in the context of surgery and childbirth.

Background: Metabolic dysfunction–associated steatotic liver disease (MASLD) is a major cause of chronic liver disease and is increasingly linked to cardiovascular disease (CVD), the leading cause of mortality globally. Aim: To evaluate individuals participating in early screening using the Hepatic Steatosis Index (HSI) and examine its association with CVD risk levels. Materials and Methods: This population-based retrospective cross-sectional study included 47,542 adults aged 40–70 years who participated in a national screening program between 2023 and 2025. Hepatic steatosis was assessed using the Hepatic Steatosis Index (HSI) and categorized as <30 (no steatosis), 30–36 (indeterminate), and >36 (steatosis). Ten-year CVD risk was estimated using laboratory-based WHO cardiovascular disease risk charts for Central Asia. Associations were evaluated using logistic regression and expressed as odds ratios (ORs) with 95% confidence intervals (CIs). Result: The mean age of participants was 53.18±8.17 years, and 67.1% (31,886) were women. The prevalence of HSI <30, 30–36, and >36 was 8.9% (4,219), 32.1% (15,271), and 59.0% (28,052), respectively. The distribution of low-, moderate-, and high-risk CVD groups was 48.6% (23,115), 41.3% (19,637), and 10.1% (4,790), respectively. The proportion of individuals with high CVD risk was 5.5% in the HSI <30 group and 10.1% in the HSI >36 group. Compared with the reference group, the odds of high CVD risk were increased in the HSI 30–36 group (OR=1.333; 95% CI: 1.152–1.542) and the HSI >36 group (OR=2.401; 95% CI: 2.094–2.753). These associations remained statistically significant after adjustment for age, sex, systolic blood pressure, waist circumference, physical inactivity, and smoking. Conclusion The prevalence of hepatic steatosis in the study population was 59.0%. Individuals with hepatic steatosis had a 1.2-fold higher risk of cardiovascular disease compared with those without steatosis.

Background: Ambient and household air pollution remain leading risk factors for global morbidity and mortality. Exposure to fine particulate matter (PM₂.₅) is associated with increased risks of cardiovascular and respiratory diseases, as well as lung cancer, metabolic and neurological disorders, and immune dysfunction. In urban areas of Mongolia, air pollution reaches critical levels during the winter season. Although improved solid fuels have been introduced in recent years, their impact on both outdoor and indoor air quality remains insufficiently characterized. Aim: To compare outdoor and household air pollution levels in Ulaanbaatar and Darkhan cities. Materials and Methods: Outdoor air pollution data for Ulaanbaatar were obtained from fixed monitoring stations of the National Agency for Meteorology and Environmental Monitoring for the period 2014–2026, with seasonal comparisons performed. For indoor air quality assessment, a longitudinal study was conducted among 240 households (apartments, houses, and traditional gers) in Ulaanbaatar and Darkhan from 2023 to 2026. PM₂.₅ concentrations were measured using real-time sensors (PurpleAir sensor), deployed for 14–21 days per season (winter and summer) in each household, recording data at 10-minute intervals over 24-hour periods. Result: Between 2014 and 2026, the 24-hour mean concentrations in Ulaanbaatar were 60.5 µg/m for PM₂.₅, 117.3 µg/m for PM₁₀, 37.3 µg/m for NO₂, 41.8 µg/m for SO₂, and 27.5 µg/m for O₃. While particulate matter levels showed a decreasing trend following the introduction of improved fuels, SO₂ concentrations increased, and overall pollution levels remained higher than those observed in Darkhan. Indoor PM₂.₅ concentrations were higher in Ulaanbaatar compared to Darkhan (60.7±86.1 vs 48.4±96.7 µg/m). Significant differences were observed by housing type (p<0.0001), with higher concentrations in households using solid fuels (houses and gers) and lower levels in apartments. These findings indicate substantial variability in indoor air pollution by city, housing type, and season, with persistently elevated exposure levels. Conclusion Outdoor air pollutant concentrations in Ulaanbaatar, including particulate matter, NO₂, and SO₂, exceed national standards and WHO guideline values by 1–4 times. Indoor PM₂.₅ pollution is higher in Ulaanbaatar than in Darkhan and varies significantly by housing type and season, indicating a high and heterogeneous exposure burden among urban populations.

Background: Dental caries remains a major public health concern among children and adolescents in Mongolia. The mineral composition of drinking water-particularly fluoride and other essential minerals plays a crucial role in enamel mineralization and caries prevention. Fluoride directly influences the demineralization–remineralization balance of dental enamel and forms a temporary layer of fluid fluorapatite on the enamel surface when exposed to acids, thereby reducing the critical pH for dissolution and increasing acid resistance. In addition, fluoride inhibits the acid-producing metabolism of bacteria such as s.mutans within the biofilm and lowers biofilm acidity, thus slowing the rate of demineralization. Therefore, determining the relationship between population groups and water mineralization is essential for developing effective preventive strategies. Aim: To determine the severity and prevalence of dental caries among 5-, 12-, and 15-year-old children living in the 21 provinces of Mongolia and to evaluate the effects of selected minerals in drinking water (Ca, Mg, Cl, F) on dental caries. Materials and Methods: The study utilized oral examination data from a total of 421,970 children aged 0-17 years across 21 provinces and 321 soums in Mongolia. Sampling was conducted in Ulaanbaatar city (48.1%) and in all 21 rural provinces. Dental caries was assessed according to WHO criteria, and the effects of minerals in drinking water were analyzed using linear regression. Result: The average caries severity of primary teeth in 5-year-old children was 3.0-3.1 dft, which was higher than the caries severity of permanent teeth in 12- and 15-year-olds (1.54DMFdft–1.93 DMFT). Among 5-year-olds, boys had a slightly higher caries severity (3.17±3.52) compared to girls (2.92±3.40), while in the 12- and 15-yearold groups, girls showed higher caries severity than boys. Overall, 5566% of children had at least one carious tooth, and the prevalence among 5-year-olds was 63.5-66.2%. Linear regression analysis showed that fluoride (beta=–0.449, p<0.001) and magnesium (beta=–0.031, p<0.001) in drinking water had a statistically significant protective effect in reducing dental caries in both primary and permanent teeth. Conclusion The findings indicate that fluoride (F) and magnesium (Mg) in drinking water are important protective elements against dental caries, whereas calcium (Ca) and chloride (Cl) show no consistent association with caries experience.

Background: Liver fibrosis is the underlying pathology of chronic liver disease complications, including cirrhosis and hepatocellular carcinoma, and its early detection is essential for preventing mortality and disease progression. Liver biopsy remains the gold standard for diagnosing fibrosis; however, it is invasive, costly, limited in repeatability, and not suitable for population-level screening. Moreover, liver fibrosis is often asymptomatic for a prolonged period, necessitating reliable and accessible methods for early identification of at-risk populations. Therefore, non-invasive approaches based on routine laboratory parameters, particularly the FIB-4 index, have been widely adopted in clinical practice. Aim: To assess liver fibrosis using the FIB-4 index and to identify risk factors associated with indeterminate and high-risk groups among individuals participating in a national early detection program in Mongolia. Materials and Methods: A total of 37,961 adults who met the inclusion and exclusion criteria were selected from 447,409 individuals who participated in the national early detection screening program between 2022 and 2023. The FIB-4 index was calculated using age, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and platelet count, and categorized as low (<1.3), indeterminate (1.3–2.67), and high (≥2.67) risk. Body mass index, blood pressure, fasting glucose, triglycerides, and viral hepatitis status were classified according to standard criteria. Statistical analyses were performed using SPSS version 21.0. Continuous variables were expressed as mean±standard deviation, categorical variables were compared using the χ² test, and logistic regression analysis was used to identify risk factors. Results: The mean age of participants was 44.96±11.31 years, with 61.3% (n=23,285) female and 38.7% (n=14,676) male. The mean FIB-4 index was 0.89±1.09. Based on FIB-4, 86.9% were classified as low risk, 11.8% as indeterminate risk, and 1.4% as high risk; overall, 13.1% (n=4,975) were in the indeterminate and high-risk groups. FIB-4 risk increased progressively with age, reaching the highest level in individuals aged ≥60 years. In multivariable logistic regression analysis, male sex (OR=1.45; 95% CI: 1.36–1.56), viral hepatitis (OR=1.85; 95% CI: 1.68–2.03), and increasing age remained independently associated with indeterminate and high risk. Underweight status and very high triglyceride levels were associated with increased risk, whereas overweight, obesity, and central obesity showed an inverse association. Conclusions 1. The FIB-4 index is a simple, cost-effective tool for identifying individuals at risk of liver fibrosis in primary healthcare settings. Male sex, older age, and viral hepatitis were independent risk factors for indeterminate and high-risk groups. 2. Therefore, the FIB-4 index can be implemented as an initial risk stratification tool in national screening programs to identify high-risk populations for further evaluation and management.

Background: An estimated 99% of the global population lives in environments where PM2.5 levels exceed the WHO air quality guideline of 15 μg/m³. In 2018, air pollution contributed to approximately 4.2 million deaths worldwide. In Mongolia, air pollution—particularly in urban centers like Ulaanbaatar, worsens significantly during the winter season, posing a serious public health and local concern. Therefore, it is compulsory to compare the outdoor air quality in Ulaanbaatar, the capital and Darkhan city. Aim: To assess and compare the outdoor PM2.5 concentrations in Ulaanbaatar and Darkhan during the winter season. Materials and Methods: This study was conducted in Ulaanbaatar and Darkhan from December 10, 2024, to February 19, 2025. A total of 60 PurpleAir Classic+ sensors (30 per city) were installed to assess PM2.5 concentrations at 2-minute intervals. We analyzed collected data using R software. The 24-hour average PM2.5 concentrations were compared with both the Mongolian National Air Quality Standard (MNS4585:2016) and the WHO air quality guidelines (2021). Results: The 24-hour average PM2.5 concentration in Ulaanbaatar was 112.3±62.2 μg/m³, which was significantly higher than that in Darkhan (79.2±25.6 μg/m³; p<0.05). In Ulaanbaatar, the monthly averages were 119.9±67.7 μg/m³ (Decem ber), 113.5±60.8 μg/m³ (January), and 95.0±51.9 μg/m³ (February) respectively (p<0.05). In contrast, Darkhan city’s monthly average PM2.5 remained relatively close across the months: 79.1±22.2 μg/m³ (December), 78.7±28.6 μg/m³ (January), and 84.6±30.0 μg/m³ (February), with no statistical significance (p>0.05). During the study period, the 24-hour average PM2.5 concentrations exceeded the MNS4585:2016 (50 μg/m³) in 69.8% of days in Ulaanbaatar and 64.6% in Darkhan. WHO’s guideline of 15 μg/m³ was exceeded 93.4% of the time in both cities. Conclusion Darkhan city has lower PM2.5 concentrations compared to Ulaanbaatar, both cities significantly exceeded MNS4585:2016 standard and the WHO air quality guidelines (2021) during the winter months.