Background: Numerous studies have shown that air pollution is a serious public health threat and risk worldwide. Mongolia is the world leader in outdoor and indoor air pollution, and the morbidity and mortality caused by it are increasing every year. People spend most of their lives indoors, and it is necessary to regularly assess and study indoor air pollution. Aim: To study the concentration of PM2.5 particles in the indoor air of households in Ulaanbaatar and Darkhan cities in relation to some symptoms of respiratory diseases. Materials and Methods: The study was conducted using an analytical cohort design from October 2023 to July 2025, and the 4 districts of the central Ulaanbaatar city and Darkhan cities were included in the study. A total of 240 households were included in the study, including 48 households living in ger and house, 24 households living in apartments, and 48 households living in ger and house, and 24 households living in apartments from Ulaanbaatar city. A direct measurement device (PurpleAir) was installed in the households for 3-4 weeks to measure PM2.5 particles in the indoor air for 24 hours. After measuring PM2.5 particles in the indoor air of the household, data were collected through questionnaires from the participants aged 18-60 who participated in the study and underwent health examinations. The results were processed using STATA-19.0 and R programs. Result: 213-239 households were selected for the study, including households living in 17-26 apartments, 42-58 houses, and 38-50 houses. The 24-hour average concentration of PM2.5 particles in the ambient air of households in Ulaanbaatar city was measured relatively higher in winter and summer than in households in Darkhan city. Among the districts of Ulaanbaatar city, the highest concentration of PM2.5 particles was measured in Songinokhairkhan district, and the lowest concentration was measured in Bayanzurkh district. Considering the cities by heating type, households with stoves are more polluted than households with centralized heating. In Darkhan city, the lowest concentration was measured in apartments (22.78-31.53 μg/m³), houses (44.53-68.17 μg/m³), and the highest concentration was measured in traditional felt houses (houses) (63.20-68.25 μg/m³). In Ulaanbaatar, PM2.5 concentrations were relatively high in all types of housing, including apartments (41.61-58.37 μg/m³), houses (79.22-92.50 μg/m³), and traditional felt dwellings (76.69-86.31 μg/m³). In the summer, PM2.5 concentrations in Darkhan were 3.10-10.03 μg/m³ in apartments, 7.67-14.37 μg/m³ in houses, and 7.98-17.90 μg/m³ in traditional felt dwellings (houses). The concentration of PM2.5 particles in the ambient air of the settlement is statistically significantly associated with shortness of breath, fatigue, weakness, muscle pain, nausea, palpitations, sneezing, runny nose, conjunctivitis, pain in the eye socket, tearing of the eyes, headache, fever, nasal congestion, cough, loss of appetite, sore throat, phlegm, wheezing, and chest pain. Conclusion The 24-hour average concentration of PM2.5 particles in indoor air in households in Ulaanbaatar and Darkhan cities is higher than the Mongolian standard during winter and is statistically significantly associated with some symptoms of respiratory diseases.

Background: Globally, gastric cancer accounts for 1,089,000 new cases and 769,000 deaths annually, ranking fifth in overall cancer incidence and third in cancer-related mortality. The aim to determine HER2 expression in patients with gastric cancer and to evaluate its correlation with clinical and immunological biomarkers, as well as the need for further laboratory diagnostics. Aim: To determine HER2 expression in patients with gastric cancer and to evaluate its association with clinical and immunological biomarkers, as well as the potential need for further laboratory diagnostics. Materials and Methods: A retrospective study was conducted using archived materials from patients with gastric cancer at the Clinical Pathology, Molecular Genetics, and Pathology Laboratories of the National Cancer Center of Mongolia, covering the period from 2019 to June 2025. HER2 protein expression in tumor tissue was assessed using immunohistochemistry (IHC), and chromogenic in situ hybridization (CISH-HER2) was employed to confirm gene amplification. Statistical analysis was performed using the Prisma-10 software. Results: In our study, among 210 cases of gastric cancer evaluated by IHC for HER2, 46 (21.9%) were HER2-positive and 164 (78.1%) were HER2-negative. When comparing patients with gastric cancer stratified into HER2 1+ (negative) and HER2 3+ (positive) groups, no statistically significant differences (p < 0.05) were observed in age, sex, tumor location (surgically resected tissue), morphology, or disease stage. However, a higher proportion of males was noted in the HER2 3+ group (80.9%), though this did not reach statistical significance (p = 0.0879). Significant associations were found with tumor markers. Elevated serum CA-72-4 (>5 ng/mL) was more frequent in the HER2 3+ group (58.8%; p = 0.0069). In contrast, elevated CA-19-9 (>35 U/mL) was more common in the HER2 1+ group (93.5%; p = 0.0117), and elevated CEA (>6.9 U/mL) was also predominant in the HER2 1+ group (90.6%; p = 0.002). These findings suggest that HER2 3+ status predominates in cases with elevated CA-72-4, which may influence diagnostic strategies and HER2-targeted therapies (e.g., trastuzumab). Conversely, elevated CA-19-9 and CEA were more associated with HER2 1+ status, indicating a need for further detailed investigation of these markers in relation to HER2 expression. In patients evaluated by CISH for HER2 expression, stratification into HER2-positive and HER2-negative groups revealed no statistically significant differences (p < 0.05) in age, sex, tumor location, morphology, stage, or serum tumor markers (CA-72-4, CA-19-9, CEA). This suggests that HER2 status (positive/negative) may be independent of these variables. Although HER2 positivity was higher in poorly differentiated tumors (48% vs. 30.6% negative; p=0.1414) and in stage IV disease (50% vs. 39.3% negative; p=0.2607), these differences were not statistically significant. Elevated serum markers (CA-72-4, CA-19-9, CEA) were observed but showed no significant correlation with HER2 status. Conclusion Determining the molecular profile of gastric cancer patients can significantly contribute to refining clinical diagnosis, developing treatment strategies, enhancing therapeutic outcomes, and improving patients’ quality of life.

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: Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder characterized by degeneration of upper and lower motor neurons, leading to muscle weakness, spasticity, dysarthria, and dysphagia. Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an autoimmune-mediated neuropathy that primarily affects nerve fibers specifically myelin sheets. Clinically, CIDP presents with distal muscle weakness, prominent sensory disturbances, and diminished or absent deep tendon reflexes. The co-occurrence of ALS and CIDP is exceptionally rare and poses significant diagnostic and therapeutic challenges due to overlapping and distinct clinical features. A Case: A 44-year-old male presented to the Department of Neurology at the Mongolia-Japan Hospital, Mongolian National University of Medical Sciences, with progressive muscle weakness in both upper and lower extremities, along with dysphagia, especially for solids with frequent choking episodes. The initial symptoms began in May 2023 with muscle fasciculations, followed by progressive weakness, initially in the right upper limb and gradually progressing to the left. By August 2023, the patient developed bilateral arm weakness, dysarthria, and worsening dysphagia. From August 2024, episodes of head drop were noted. A progressive weight loss of 11 kg was recorded since January 2024. Comprehensive neurological evaluation, including antibody profiling, electromyography (EMG), and nerve conduction studies (NCS), supported a diagnosis of amyotrophic lateral sclerosis with chronic inflammatory demyelinating polyradiculoneuropathy-like neuropathy. Outcome: One month after hospital discharge, the patient demonstrated improvement in self-care abilities and increased muscle strength in both proximal and distal upper limb muscles. Notably, there was marked improvement in overall clinical status. Conclusion To our knowledge, this is the first reported case in Mongolia documenting the simultaneous presentation of ALS and CIDP-like neuropathy. Globally, such cases are exceedingly rare. Timely and accurate diagnosis, along with appropriate treatment, contributed to improved clinical outcomes and a deceleration of disease progression in this patient.

Background: According to the World Health Organization (WHO), air pollution was responsible for 8.1 million deaths globally in 2021, making it the second leading cause of death, including among children under 5 years old. Air pollution is also linked to a range of diseases such as stroke, chronic obstructive pulmonary disease, lung cancer, and asthma. In Ulaanbaatar, the capital of Mongolia, the average daily concentration of PM2.5 particles in the air reaches 750 μg/m3 during winter, which is 50 times higher than the WHO’s recommendation, making it one of the most polluted cities in the world. Air pollution continues to pose a significant public health challenge not only in Mongolia but also in many countries globally. However, there is a lack of comprehensive research and studies that summarize and review the existing work in this field. Aim: To summarize and review thematic works on air pollution conducted by researchers from Mongolian universities. Materials and Methods: A systematic review and analysis were performed on thematic works by researchers who completed their master’s and doctoral degrees in the field of air pollution between 2011 and 2024. Results: In terms of the type of master’s and doctoral dissertations, 76.0% (n=19) were master’s theses and 24.0% (n=6) were doctoral dissertations. Among the total number of works included in the study, 36.0% (n=9) focused on the health effects of air pollution, while 64.0% (n=16) addressed other related areas. Some studies indicated that PM2.5 levels in the air between 2011 and 2024 were 1-6 times higher than the Mongolian standard, with the highest levels observed from November to February and the lowest in July. Additionally, some studies suggested a reduction in PM2.5 levels following the introduction of improved fuel in Ulaanbaatar. Air pollution was found to increase the risk of respiratory and cardiovascular diseases, as well as cancer, and to contribute to reduced fetal weight. Conclusion When examining thematic studies on air pollution conducted by state-owned universities in Mongolia, the primary focus has been on the composition, concentration, and health impacts of air pollution. Going forward, research aimed at mitigating air pollution should be driven by collaborative efforts and leadership from universities, with the results being effectively communicated to policymakers.

Background: Accreditation of healthcare institutions serves as a fundamental mechanism for ensuring patient safety and validating the quality of medical services provided to the population. At Intermed Hospital, a quality measurement system for healthcare services has been established since 2015, encompassing 126 quality indicators at both institutional and departmental levels. This system facilitates continuous quality improvement efforts. In this context, quality indicators specific to the endoscopy department play a pivotal role in objectively assessing the quality of endoscopic services. Aim: To assess the quality indicators in gastrointestinal endoscopy unit. Materials and Methods: A retrospective single-center study was conducted by collecting data from the Intermed hospital’s electronic information systems which included HIS and PACS and Quality and Safety Department’s Database and the results were processed using the SPSS software. Ethical approval was granted by the Intermed hospital’s Scientific research committee. The quality of endoscopic services in the Intermed hospital was assessed based on: a) the average values of four quality indicators measured monthly; b) sample survey data from five categories of quality indicators. Results : Between 2016 and 2024, the quality indicators of the endoscopy unit measured as the level of early warning score evaluations for patients was 95.97%±3.33, the level of cases where peripheral blood oxygen saturation decreased during sedation was 1.54%±3.78, the level of cases where patients experienced paradoxiical response during sedation was 5.82%±1.75, surveillance culturing level for validation of endoscopy reprocessing was 11.6%. The endoscopic documentation quality by peer review showed 95.7-100%, the colonoscopy quality indicators were followings as adenoma detection rate: 24.5% Cecal intubation rate: 99.1%, 95.2%, Colonoscope withdrawal average time: 13.28±10.62 minutes, Bowel preparation quality (Boston Scale): 89.3% 95.7%), patient discharge from the recovery room, Average discharge time post-procedure: With propofol alone: 30.92 minutes; With propofol and fentanyl combined: 31.52 minutes, The intermediate risk was 0.28% by the TROOPS evaluation during procedural sedation. Conclusion The quality benchmark levels for these endoscopic units, as determined by a single-center study, can be effectively implemented by benchmark endoscopy centers to enhance their quality and safety operations.

Introduction: Lung cancer is the leading cause of cancer-related deaths in the world, and half of all new cases (59.6%) are recorded in Asia. Smoking remains the leading cause of death from lung cancer and COPD, followed by air pollution. Therefore, in Ulaanbaatar, where the population concentration is high and air pollution is high, there is a need to study the new cases and deaths of lung cancer in detail. Purpose: It is aimed to evaluate the prevalence of new cases and deaths of lung cancer among the population of Ulaanbaatar. Materials and Methods: This study analyzed new cases and deaths diagnosed with lung cancer from 2013 to 2023 in the city of Ulaanbaatar using a single-moment design of descriptive research. The quantitative data of the study included the diseases recorded using the International Classification of Diseases X (ICD-10) and lung cancer codes C-33 and C-34. The numerical data collected during the research were processed in the Microsoft Office Excel-13 program and processed using the IBM SPSS Statistics 23 program. Results: A review of the newly registered lung cancer epidemic in Ulaanbaatar from 2014-2022 has observed an increase in the number of new cases recorded in Songinokhairkhan, Sukhbaatar, Khan-Uul, and Baganuur districts in those years and in recent years in the Bayanzurkh and Sukhbaatar districts. Men were three times more likely than women to develop lung cancer, with new cases and deaths highest in the 55-69 age group. The cancer diagnosis was diagnosed using imaging devices. Of the total cases diagnosed, 9 out of every 10 people diagnosed are diagnosed later, or 3.4 per cent, and 69.5 per cent are diagnosed with jumping stages. Conclusion Although the number of new cases and deaths among the population of Ulaanbaatar is relatively lower than the national average, there has been an increasing trend in recent years.

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.

Background: Minerals are important for the proper body functioning. They also play a role in preventing and fighting diseases. Reference values for minerals help physicians evaluate the mineral status of patients and make clinical decisions. The aim of this study was to determine the mean values and reference intervals for some minerals to be used for evaluation of the nutrition status of Mongolians. Materials and Methods: Two hundred and forty healthy adults (120 males and 120 females) of 17 to 70 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 ethical committee of the Ministry of Health of Mongolia. Informed consents were taken from the selected individuals. Morning blood samples of the participants were collected under aseptic conditions. Levels of iron (Fe), zinc (Zn) and copper (Cu) were measured by graphite furnace atomic absorption spectrometry. 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 level of blood iron was 30.50 µmol/L (95% CI 29.71-31.29) for men and 30.91 µmol/L (95% CI 30.03-31.79) for women. The calculated reference interval for males was 21.39-37.72 µmol/L and 19.87-39.67 µmol/L for females. The mean concentration of zinc in the blood of males was 11.00 µmol/L (95% CI 10.69-11.31) and that of females was 11.79 µmol/L (95% CI 11.39-12.19). The reference interval for blood zinc was 8.20-14.92 µmol/L in men and 8.52-16.67 µmol/L in women. The mean level of blood copper was 15.28 µmol/L (95% CI 14.64-15.89) for men and 18.08 µmol/L (95% CI 17.30-18.86) for women. The calculated reference interval for copper in males was 9.72-22.34 µmol/L and that in females was 11.18-27.27 µmol/L. Conclusion The reference values for zinc, copper and iron of Mongolian adults do not differ significantly from those observed in other countries. The calculated reference intervals can be used for evaluation of the nutrition status and making clinical decisions.

Background: Reference values are very important for the clinical decisions in laboratory diagnosis and clinical management of patients. Method: A total of 340 adults (apparently healthy individuals) between 18 to 70 years resident in the Ulaanbaatar city were randomly selected and enrolled in this survey. 340 adults made up of 170 males, 170 females were assessed by a clinician to be healthy. About 5 ml of blood was collected with EDTA test tube and analyzed using automated analyser to enumerate the hematological parameters (red blood cell, white blood cell, hemoglobin and haematocrit). Reference values were determined at 2.5^th and 97.5^th percentiles. Results: Reference values estabilished include: red blood cell 4.69-6.04×1012/L, white blood cell 3.98-9.11×109/L, haemoglobin 145-176 g/L, haematocrit 42.6-52.9% for males and red blood cell 4.10-5.20×1012/L, white blood cell 3.50-9.08×109/L, haemoglobin 121.8-148.2 g/L, haematocrit 36-44.7% for females. Conclusion We were determined mean and reference range of haematological parameters (red blood cell, white blood cell, haemoglobin, haemotocrit) which are important for assessing the nutritional status of adults according to the international standard methodology. The international reference range shows that white blood cells counts do not indicate gender and our data (р=0.0964 are statistically insignificant) also offers no significant difference was found between samples for male and female subjects.