Background: According to the World Health Organization (WHO), 99 percent of the world’s population is exposed to air that exceeds WHO recommendations, with low- and middle-income countries being the most affected. The main causes of indoor air pollution include human activities such as fuel burning, cooking, cleaning, and smoking; housing characteristics such as walls, floors, ceilings, and furniture; ventilation; and outdoor air pollution. Aim : To assess PM1 and PM10 concentrations in 120 selected households in Ulaanbaatar. Materials and Methods : Indoor PM1 and PM10 concentrations were measured using Purple Air real-time sensors in randomly selected Ulaanbaatar households between October 2023 and January 2024. Supplementary data on factors affecting the PM2.5 concentration were collected via questionnaires. Each measurement was taken in 10-minute intervals, yielding 51,309 data for analysis. Results : PM1 concentrations were measured at 55.5±53.2 μg/m³ in gers, 54.9 ± 46.7 μg/m³ in houses, and 31.6±40.1 μg//m³ in apartments (p<0.001) and measuring PM10 concentrations were 110.6±108.6 μg/m³ in gers, 110.6±96.7 μg/m³ in houses, and 62.2±83.0 μg/m³ in apartments (p<0.001) When considering the concentration of PM1, PM10 by heating type, PM1 was 55.3±50.1 μg/m³ and PM10 was 110.6±103.0 μg/m³ in households with stoves and furnaces, and PM1 was 31.6±40.1 μg/m³ and PM10 was 62.2±83.0 μg/m³ in households connected to the central heating system (p<0.001). Regarding the months of measurement, the highest concentration was observed in December 2023, at 77.1±94.1 μg/m³. The highest concentrations for both PM₁ and PM₁₀ were recorded in January 2024, at PM₁: 64.8±55.1 μg/m³, PM₁₀: 131.4±116.0 μg/m³. Conclusion 1. Indoor PM10 concentrations in residential environments in Ulaanbaatar city were within the MNS4585:2016 Air Quality Standard, however, it was exceeded the WHO air quality guidelines, indicating an excessive risk of increasing morbidity and mortality among the population. 2. Indoor PM1 and PM10 concentrations in residential environments in Ulaanbaatar varies depending on location, type of housing, type of heating, and month of measurement.

Background: Demyelinating disorders are a group of chronic immune-mediated diseases affecting myelinated axons in the central nervous system, which lead to life-long disability. In Mongolia, the last regional prevalence study was conducted in 2010. Our study objective is to describe the current prevalence of multiple sclerosis (MS) and other demyelinating disorders in Mongolia. : Aim Materials and Methods: We registered MS, neuromyelitis optica spectrum disease (NMOSD), myelin oligodendrocyte glycoprotein (MOG), and acute disseminated encephalomyelitis (ADEM) cases diagnosed according to the 2017 McDonald criteria, the 2023 NMOSD diagnostic criteria, International MOGAD Panel proposed criteria. Results: The study was conducted in all tertiary, 7 regional, and 20 provincial hospitals across Mongolia and has collected comprehensive data on 965 patients. The prevalence of total demyelinating disorders was estimated to be 27.2, MS 15.6, NMOSD 5.6, MOG 0.06, and ADEM 0.9 per 100,000 total population, respectively. The prevalence of demyelinating disorders between provinces was compared in order of geographical latitude, from lowest to highest, and was statistically significant. Latitude is associated strongly with the prevalence of demyelinating disorders (p=0.006, 95% CI 14.3-22.4, Pearson correlation=0.603) and moderately with the prevalence of MS (p=0.028, 95% CI 9.39-15.6, Pearson correla tion=0.503). Conclusion In Mongolia, the prevalence of MS has significantly increased and can be considered at medium risk, but still much lower than that in Western countries. The prevalence of NMOSD is almost similar to other Asian countries. An obvious latitude gradient for demyelinating disorders was observed in the Mongolian population.

Background: A 2018 study on the global burden of disease, accidents, and risk factors reported that 1.6 million peo ple died in 2017 due to household air pollution. Poor indoor air quality has been highlighted as a contributing factor to respiratory diseases, cardiovascular conditions, and exacerbation of asthma and allergies. A 2019 study estimated that long-term exposure to fine particulate matter (PM2.5) with a diameter of 2.5 micrometers or less reduces average life expectancy by 1.8 years, with more severe effects in highly polluted regions. Additionally, a study by Miller et al. (2007) found that prolonged exposure to PM2.5 increases the risk of cardiovascular diseases, particularly among women. Direct measurement devices are highly effective in determining indoor PM2.5 concentrations, identifying sources of pollution, tracking pollutant dispersion, and monitoring temporal variations. Studies suggest that direct measurement is an accurate, cost-effective method that provides detailed data suitable for local conditions. Aim: To investigate the indoor air quality of houses and apartments in Darkhan city during the winter season using the Purple Air monitoring device. Materials and Methods: A cross-sectional study was conducted with a targeted sample of 128 households in Darkhan city. The study examined factors such as stove type, type of coal used, annual and daily coal consumption, frequency of heating, and chimney sealing conditions. To collect data, the Purple Air monitoring device was installed in each house hold for a month, after which it was retrieved. During retrieval, participants completed a questionnaire. The questionnaire consisted of 55 questions across 7 pages at the time of device installation and 25 questions across 3 pages at the time of device retrieval. The collected data was analyzed using SPSS 25.0. Results: A total of 128 households in Darkhan city participated in the study. The average duration of residence in the current home was 9.5 years, with no statistically significant variation. The distribution of housing types was as follows: traditional Mongolian gers (40.6%), houses (39.1%), and apartments (20.3%). The 24-hour average PM2.5 concentration was highest in gers (70.9 μg/m³), followed by houses (46.8 μg/m³) and apartments (22.8 μg/m³), with a statistically significant difference (p=0.0001). PM2.5 levels were most variable in gers, followed by houses and then apartments. House holds using central heating (apartments) had an average 24-hour PM2.5 concentration of 22.8 μg/m³, whereas households using stoves (gers and houses) had a significantly higher concentration of 59.4 μg/m³ (p=0.0001). However, there was no statistically significant difference between traditional and improved stoves. Among study participants, 21.4% reported that someone in their household smoked indoors. Additionally, 86.5% regularly burned incense, candles, or herbs, while 99.2% did not use an air purifier. Conclusion The indoor particulate matter concentration in houses and gers in Darkhan was 59.4μг/m3. Variations in stove types, poor chimney sealing limited space, and frequent gaps and cracks contribute to increased spread of indoor air pollutants.

Background: The main risk factors for childhood overweight and obesity include the consumption of sugar-sweetened beverages and other sweetened foods. The sugar content of sugar-sweetened beverages was different from the nutritional information on the packaging. Aim: To determine sugar and brix content in domestic manufactured sugar-sweetened beverages, and compare information on the packaging and regulatory standards. Materials and Methods: The sugar and brix content in sugar-sweetened beverages was determined by laboratory anal ysis, including 150 domestically manufactured sugar-sweetened beverages. Laboratory analysis carried out in the Chemical toxicology laboratory of the National Reference Laboratory for Food Safety, MASM, determined sugar using a saccharometer and brix using refractometry. : Results: The study included 150 Mongolian sugar-sweetened beverages, including 20.7% (n=31) carbonated drinks, 47.3% (n=71) fruit drinks, 16.0% (n=24) tea drinks, 1.3% (n=2) energy drinks, 14.7% (n=22) flavored water. Sugar content 0.0–15.6% in sugar-sweetened beverages. The laboratory analysis results compared with information on the packaging 72.0% (n=108) difference between 0.1–11.3%, 10.7% (n=16) same, do not have sugar content in the nutritional information on the packaging 17.3% (n=26). Brix contained 0.2–13.0% carbonated drinks, 4.9–15.7% fruit drinks, 0.6–9.8% tea drinks, 7.7–16.0% energy drinks, and 0.1–9.7% flavored water. Conclusions 1. Sugar content 0.0–15.6%, brix 0.0–16.0% in Mongolian sugar-sweetened beverages. 2. The laboratory analysis results compared with nutritional information on the packaging 72.0% (n=108) difference between 0.1–11.3%, 10.7% (n=16) same nutritional information on the packaging, do not have sugar content in the nutritional information on the packaging 17.3% (n=26). 3. 37.3% of Mongolian sugar-sweetened beverages are unsatisfied with regulatory standards.

Background: Nutritional status among university students is a critical public health issue. Students often face undernutrition or overeating due to social, cultural, and academic pressures. This study aimed to assess the dietary habits and health behaviors of students at Inner Mongolia Medical University to inform targeted intervention strategies. Aim: To examine the differences in dietary patterns among students and their effects on health outcomes. Materials and Methods: A cross-sectional study was conducted among 218 students (133 males, 85 females; ages 19–24) from the 3rd to 5th year of the Clinical Medicine program. Participants were randomly selected. Data were collected via a structured questionnaire based on the “Chinese Resident Dietary Guidelines (2022)” and relevant domestic and international literature. Variables included demographic information, dietary intake (fruits, vegetables, fats, starches, sugar, salt, water, alcohol, dairy), and physical activity patterns. Data were analyzed using SPSS 26.0, with frequencies and percentages for categorical variables and means ± SD for continuous variables. Results: The 87.61% of students consumed fruits and vegetables daily, but only 73.39% met the recommended five types per day. The main barriers were limited availability (51.38%), high cost (31.65%), and lack of preparation time (16.97%). 67.89% preferred low-fat foods; 47.25% used vegetable oil, 22.94% butter, 22.02% margarine; daily fat consumption averaged 1–2 tablespoons. 77.98% consumed fried or roasted foods. 53.21% consumed sugar-rich products at breakfast; 62–64% added sugar to beverages or consumed sweetened snacks; high salt intake was common through processed foods. The 36.24% exercised once per week, 25.69% twice; only 10.09% exercised four or more times per week. 68.81% consumed alcohol at varying frequencies; beer, red wine, and white wine were common. Over half of students were at risk of high blood pressure due to dietary and lifestyle factors. Conclusion Students at Inner Mongolia Medical University face significant dietary challenges, including unbalanced diets, high sugar and salt intake, irregular meals, and inadequate physical activity. There is an urgent need for personal and institutional interventions to promote healthy dietary and lifestyle habits.

Backgroun: Air pollution is a major global public health concern that poses serious risks to human health regardless of a country’s level of economic or technological development. According to the World Health Organization (WHO, 2021), nine out of ten people worldwide breathe polluted air, and air pollution is responsible for the deaths of approximately 800 people every hour and 13 people every minute. Prolonged exposure to polluted air has been linked to a wide range of chronic illnesses, including chronic obstructive pulmonary disease (COPD), lung and bronchial cancers, asthma, and stroke. In Mongolia, air pollution reaches its highest levels during the winter months, particularly in Ulaanbaatar, where the majority of the country’s population resides. A study conducted by Enkhjargal G. (2012) reported that the concentrations of PM10 and PM2.5 in Ulaanbaatar were 7–8 times higher than the WHO recommended guidelines. In response to such challenges, many countries have increasingly adopted low-cost, direct measurement devices such as PurpleAir to monitor air quality. These devices are valued for their accessibility, network connectivity, and potential role in smart city pollution management systems. Despite their global application, there remains a lack of research in Mongolia on the use of PurpleAir sensors to measure PM2.5 concentrations and compare the results with official monitoring station data. Addressing this gap is essential for improving local air quality monitoring capacity and informing effective public health and environmental policies. Aim: Determination of PM2.5 particulate matter pollution in the outdoor environment of Ulaanbaatar city using a direct measurement device (Purple Air). Materials and Methods: A cross-sectional study design was employed. Direct measurement devices (Purple Air) were installed in selected districts of central Ulaanbaatar between December 2024 and February 2025, measuring PM2.5 concentrations at two-minute intervals over 24-hour periods. All data were statistically processed and analyzed using the SPSS-26 software package. Results: The average concentration of PM2.5 particles in the air of Ulaanbaatar city in winter is 66.68 μg/m3. Compared to the districts, the highest concentration was determined in SKHD (118.58±90.22 μg/m3), while the lowest concentration was determined in KHUD (42.37±43.51 μg/m3). Compared to the days of the week, the highest concentrations were measured on Monday (76.68±71.98 μg/m³), Saturday (77.50±71.63 μg/m³), and Sunday (80.34±74.45 μg/m³). The highest concentration of PM2.5 particles occurred from 6 pm to 1 am, and the lowest concentration was measured during the day (between 2 pm and 4 pm). The highest concentration of PM2.5 was measured in December (74.22±73.45 μg/m3), while the lowest concentration was measured in February (50.25±57.44 μg/m3). Conclusion The concentration of PM2.5 in the air of Ulaanbaatar city is 1.7 times higher than the general standard and technical requirements of Mongolia in winter, and the highest concentration is in the SKHD. The highest concentration of PM2.5 occurs more often in December and at night than in the winter months.

Background: Particulate matter with an aerodynamic diameter of 2.5 micrometers or smaller (PM2.5) penetrates deep into the alveoli through the respiratory tract and is characterized by its ability to induce oxidative stress, systemic inflammation, and vascular inflammation. Mongolia ranks among the countries with the highest levels of air pollution. In Ulaanbaatar, where more than half of the country’s population resides, wintertime PM2.5 concentrations often exceed 200 μg/m³, which is about eight times higher than the World Health Organization (WHO) guideline value. A study involving 1,200 adults in Ulaanbaatar showed that quality of life deteriorated sharply during periods of high air pollution, with effects more pronounced among individuals who already had impaired respiratory function. Aim: To examine the relationship between indoor household PM2.5 concentrations and lung function indicators among adults in Ulaanbaatar and Darkhan. Materials and Methods: This analytical cross-sectional study recruited adult participants from Ulaanbaatar and Darkhan through targeted sampling. Household air quality was measured using PurpleAir sensors, which were installed in participants’ homes for one month. After exposure measurement, lung function was assessed via spirometry. Statistical analyses were conducted using SPSS version 25.0. Results: A total of 236 participants were included: 114 (48.3%) from Ulaanbaatar and 122 (51.7%) from Darkhan. The sample consisted of 111 men (47.0%) and 125 women (53.0%). The mean indoor PM2.5 concentration was 66.24 μg/m³ (SD 44.87 μg/m³), ranging from a minimum of 7.79 μg/m³ to a maximum of 264.55 μg/m³. Stratification by housing type showed the highest PM2.5 levels in gers (82.34 μg/m³), followed by detached houses (67.34 μg/m³), while apartments had the lowest concentrations (32.24 μg/m³). Correlation analysis revealed statistically significant negative associations between PM2.5 levels and measures of expiratory function, including the FEV1/FVC ratio, peak expiratory flow (PEF), and mid-expiratory flow (FEF25–75). Reduced forced vital capacity (FVC) was observed in 9.4% of participants, reduced forced expiratory volume in one second (FEV1) in 15.3%, and a decreased FEV1/FVC ratio in 3.8%. Conclusion Indoor household PM2.5 concentrations were highest in gers, and expiratory flow-related lung function parameters showed significant negative associations with particulate exposure. This suggests that indoor PM2.5 primarily affects airflow limitation rather than overall lung volumes in this population.

Background: Since August 2021 in Mongolia, the rapid spread of the SARS-CoV-2 Delta variant among the population coincided with the reopening of all levels of educational institutions, including universities, general education schools, and kindergartens, for in-person learning. Aim: To examine the impact of the measures implemented when school was reopened with in-person learning on COVID-19 morbidity among school children, to assess the overall infection situation in children, and to determine whether any school-based outbreak clusters occurred during the Delta variant surge. Materials and Methods: This study used national data from confirmed COVID-19 cases recorded in the electronic surveillance system between January 1, 2021, and February 28, 2022, including all cases and those among children aged 0-17 years. The 7-day moving average of the proportion of cases among children was calculated, representing the average proportion of pediatric cases during the preceding seven days. Additionally, the study compared the incidence and relative risk (RR) of COVID-19 among children aged 0-17 years at the time of school reopening on September 1, 2021, with those observed during previous outbreaks caused by the SARS-CoV-2 Wuhan, Alpha, and Omicron variants. As vaccination was available only for adolescents aged 12-17 years, the analysis was stratified by three age groups: 0-4, 5-11, and 12-17 years. Results: Throughout the study period, the proportion of COVID-19 cases among children aged 0–17 years nationwide ranged from 0.73% to 5.93% across outbreaks caused by the four SARS-CoV-2 variants (min 0.73%; max 8.57%). The 14-day confirmed case rate per 10,000 population was highest during the Delta (107.57) and Omicron (113.56) variant outbreaks. When comparing age groups, children aged 5–11 years were used as the reference group. During outbreaks, the relative risk for the 12–17-year group was lowest during the wild-type virus wave (RR=0.47) and highest during the Delta wave (RR=0.78). Conclusion During COVID-19 outbreaks, the proportion of pediatric cases (0-17 years) among total cases ranged from 0.73% to 5.93%, consistent with findings from studies conducted in other countries. Overall, infection rates were higher among the 0-4 and 12-17 age groups, with the highest rates among 0-4-year-olds during the Delta variant outbreak. No clustered outbreaks involving six or more cases were reported in school settings. Future studies should focus on assessing the transmission dynamics of respiratory infections among children in both household and school settings, especially during influenza and influenza-like illness outbreaks, to generate evidence for preventive measures against respiratory pathogen transmission.

Background: Hepatocellular carcinoma (HCC) remains one of the leading causes of cancer-related mortality worldwide and in Mongolia. Alcohol-related liver disease (ALD) and metabolic dysfunction-associated steatohepatitis (MASH) are two major etiological factors contributing to the rising burden of HCC, each presenting distinct clinical and pathological characteristics. Aim: To compare the clinical, pathological, and survival characteristics of patients with ALD-related HCC and MASH-related HCC who underwent liver resection. Material and Methods: A retrospective cohort study was conducted using clinical and pathological data from 980 patients who underwent liver resection between 2010 and 2024. Among them, 191 were categorized into the ALD group and 789 into the MASH group. Clinical parameters, laboratory findings, tumor pathology (size, grade, fibrosis stage, vascular invasion), recurrence, and overall survival (OS) were analyzed. A simulated Kaplan–Meier survival curve was generated based on group-level survival estimates. Results: Patients with ALD were significantly younger and predominantly male compared with those in the MASH group (p=0.0014; p<0.0001). The MASH group demonstrated more aggressive pathological features, including larger tumors (>5 cm), poorer differentiation (G3–4), advanced T4 stage, and a higher rate of large-vessel invasion (all p<0.05). Despite these findings, the MASH group showed a longer mean overall survival (92.6 months) than the ALD group (82.0 months; p=0.0206). Conclusion Although MASH exhibits more aggressive pathological features compared with ALD, patients in the MASH group demonstrated better overall survival. These findings underscore the importance of incorporating etiological differences into the diagnostic, therapeutic, and postoperative management strategies for HCC.

Background: Vitamins are nutrients essential for human health. They act as coenzymes that help trigger important chemical reactions necessary for energy production. Reference values for vitamins help physicians evaluate the health status of patients and make clinical decisions. The aim of this study was to determine the mean values and reference intervals for some water-soluble vitamins of Mongolian adults. Materials and Methods: Three hundred and forty healthy adults (170 males and 170 females) of 17 to 69 years of age were selected for the study based on CLSI C28-P3 criteria Defining, establishing & Verifying reference interval in the clinical laboratory; Proposed Guidelines. The study was approved by the Resolution No.76 of 2018 of the Medical Ethics Review Committee of the Ministry of Health. Informed consents were taken from the selected individuals. Morning blood samples of the participants were collected under aseptic conditions. Levels of vitamins B₆, B₉, B₁₂ and vitamin C were measured using a high performance liquid chromatography method. The lower- and upper reference limits were defined as the 2.5th and 97.5th percentiles, respectively. The data were analyzed using SPSS and Excel programs. Results: The mean blood level of vitamin C was 11.88 mg/L (95% CI 10.47-13.29) for men and 9.62 mg/L (95% CI 8.11-11.13) for women. The calculated reference interval for males was 1.40-19.40 mg/L and 1.17-18.04 mg/L for females. The mean concentration of vitamin B₁₂ in the blood of males was 938.45 ng/L (95% CI 747.22-1129.68) and that of females was 864.03 ng/L (95% CI 603.81-1124.25). The reference interval for vitamin B₁₂ was 233.03-1597.00 ng/L in men and 132.45-1623.86 ng/L in women. The mean level of vitamin B₉ was 8.47 ng/mL (95% CI 5.64-11.30) for men and 6.91 ng/mL (95% CI 4.89-8.93) for women. The calculated reference interval for this vitamin in males was 1.04-24.74 ng/mL and that in females was 1.04-21.46 ng/mL. As for vitamin B₆, the mean concentration for men was 44.42 ng/mL (95% CI 37.01-51.83) and for women was 34.67 ng/mL (95% CI 29.97-39.39) with the reference intervals of 5.90-79.02 ng/mL for men and 5.27-61.72 ng/mL for women. Conclusion The reference values for vitamins B₆, B₉, B₁₂ and vitamin C of Mongolian adults do not differ significantly from those observed in other populations. The calculated reference intervals can be used in the practice of health laboratories.