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: 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: The COVID-19 pandemic has profoundly impacted mental health, particularly exacerbating conditions such as depression, anxiety, insomnia, post-traumatic stress disorder (PTSD), and emotional disorders among hospitalized patients. This study examined the prevalence of COVID-19-related mental health issues and risk factors in hospitalized patients affiliated with MNUMS, compared to a control group. Aim: To assess the prevalence of mental health disorders such as depression, anxiety, insomnia, and post-traumatic stress disorder (PTSD), and to identify their associated risk factors. Materials and Methods: The study was conducted at hospitals under MNUMS, including the Mongolian-Japanese Hospital, Central Hospital, and the National Center for Maternal and Child Health. A total of 552 participants (399 case group, 153 control group) who were hospitalized were included. Depression (PHQ-9≥10), anxiety (GAD-7≥10), insomnia (ISI≥15), and PTSD (PCL-5≥33) were assessed using standardized scales. Analysis was performed using chi-square tests and binary logistic regression (crude odds ratio [cOR]/adjusted odds ratio [aOR], 95% confidence interval [CI]), adjusted for group, age, and sex. Results: In the case group, depression (23.1% vs. 13.7%, p=0.015, cOR=1.884 [1.124-3.156]), anxiety (16.8% vs. 11.1%, p=0.096), and any mental disorder (18.0% vs. 13.7%, p=0.225) were higher, while insomnia was lower (19.5% vs. 30.1%, p=0.008). PTSD was low overall (1.8% vs. 0.7%, p=0.333). Risk factors included female sex (p<0.001, cOR=0.362 for depression in males), younger age (p=0.004), unemployment (p=0.017), and prior trauma (p<0.001). COVID-19 symptoms (difficulty breathing) increased the risk of depression (p<0.001, cOR=2.828 [1.708-4.682]). Conclusion Hospitalization for COVID-19 increases the risk of depression and anxiety, modulated by demographic, clinical, and socioeconomic factors. Targeted interventions for vulnerable groups are essential.

Background: COVID-19, first identified in Wuhan, China, in December 2019, was declared a global pandemic by the WHO on March 11, 2020, leading to over 770 million infections and 7 million deaths worldwide. In Mongolia, the first case emerged on March 10, 2020, followed by more than 1 million infections and over 2,100 deaths by 2023. The virus affects the central nervous system, manifesting as depression, anxiety, insomnia, and PTSD through biological pathways (e.g., ACE-2 receptor invasion, cytokine storm) combined with psychological stressors (e.g., fear, isolation). Global studies (WHO Mental Health Atlas 2022; Ettman et al., JAMA 2020; Huang et al., Lancet Psychiatry 2021; Xie et al., BMJ 2022) indicate a 25–40% rise in depression and anxiety during the pandemic’s first year, with 30–60% of infected individuals experiencing persistent symptoms 6–12 months post-infection. In Mongolia, cross-sectional surveys (National Center for Mental Health 2021: 28.7% moderate-to-severe depression, 22.4% high anxiety) have been conducted, but long-term prospective data remain scarce. This study evaluates longitudinal changes in depression, anxiety, insomnia, and PTSD among COVID-19 patients over 12 months, compared to a control group. Aim: To conduct long-term follow-up and comparative assessment of depression, anxiety, insomnia, and post-traumatic stress disorder (PTSD) among individuals who have had COVID-19 Materials and Methods: In this prospective cohort study, 459 adults (326 COVID-19 cases, 133 controls) were recruited from MNUMS-affiliated hospitals, Central Hospital, and the National Center for Maternal and Child Health between 2021 and 2023. Participants without baseline mental disorders underwent follow-up assessments at 14 days, 3 months, and 12 months using validated scales: PHQ-9 (depression), GAD-7 (anxiety), ISI (insomnia), and PCL-5 (PTSD). Incident cases were identified through baseline exclusion. Data were analyzed via χ² tests, t-tests, relative risk (RR) calculations, and multivariable logistic regression (p < 0.05). Results: Baseline demographics were comparable between groups (mean age 46.3 ± 13.8 years; 58.4% female). At 12 months, the COVID-19 group exhibited higher rates of depression (37.3% vs. 16.9%; RR = 2.22, 95% CI: 1.28–3.83, p = 0.003) and anxiety (28.0% vs. 11.2%; RR = 2.49, 95% CI: 1.25–4.96, p = 0.006). Insomnia was lower in the COVID-19 group (33.3% vs. 49.4%; RR = 0.67, p = 0.037), while PTSD rates remained low (<3%, p > 0.05). Adjusted odds ratios confirmed COVID-19 as an independent predictor of depression (aOR = 2.18) and anxiety (aOR = 2.41). Females and individuals aged 40–59 years were at elevated risk. Conclusions 1. In the cohort of individuals who had contracted COVID-19, levels of depression after 12 months were 2.2 times higher, levels of anxiety were 2.5 times higher, and levels of insomnia were 0.67 times lower compared to the control group. 2. Post-traumatic stress disorder was observed in 3.1% of participants 14 days post-exposure, but was not detected after 12 months; this resolution is posited to be associated with the adaptive capacity of the population. 3. COVID-19 constitutes a long-term independent risk factor for the onset of depression and anxiety.

Objectives: Infections with hepatitis B, C, and D virus (HBV, HCV, and HDV) are a major public health problem and lead to serious complications such as cirrhosis and hepatocellular carcinoma. We aimed to determine the seroprevalence of hepatitis B surface antigen (HBsAg), anti-HCV, anti-HDV immunoglobulin G, alpha-fetoprotein (AFP), and dual and triple hepatitis virus infections in Mongolia. Methods: A total of 2313 participants from urban and rural regions were randomly recruited for this cross-sectional study. A questionnaire was used to identify the risk factors for hepatitis virus infections, and the seromarkers were measured using immunoassay kits. Results: Among all participants, the prevalence of HBV, HCV, and HDV was 15.6%, 36.6%, and 14.3%, respectively. The infection rates were significantly higher in females and participants with a lower education level, rural residence, older age, and a history of blood transfusion. HBV and HCV co-infection was found in 120 (5.2%) participants and HBV, HCV, and HDV triple infection was detected in 67 (2.9%) participants. The prevalence of elevated AFP was 2.7%, 5.5%, and 2.6% higher in participants who were seropositive for HBsAg (p=0.01), anti-HCV (p<0.001), and anti-HDV (p=0.022), respectively. Elevated AFP was more prevalent in participants co-infected with HBV and HCV (5.8%, p=0.023), HBV and HDV (6.0%, p<0.001), and triple-infected with HBV, HCV, and HDV (7.5%) than in uninfected individuals. Conclusions Nearly half (49.8%) of the study population aged ≥40 years were infected with HBV, HCV, or HDV, and 22.4% had dual or triple infections.

Background: Thyroid nodules (TNs) are a common clinical issue, and their prevalence has been increasing over the last 2 decades [1] due to the widespread use of ultrasound (US) imaging. More than 50% of TNs are detected with US examination In the general population, while only 3–7% are detected with palpation [2]. Nodular goiter is the most common cause of thyroid disease in Mongolia, as in other countries. Recent guidelines suggest that a nodule without clinical symptoms should be treated with watchful waiting; however, some patients require treatment because of cosmetic problems or symptoms. There are several treatment options, but neither is perfect. The main treatment of the disease is still the traditional surgical resection. it still carries a 2–10% prevalence of complications, such as neck scarring, hypothyroidism, transient or definitive postoperative hypoparathyroidism, recurrent laryngeal nerve injury, and the recognized risks associated with general anesthesia [3,4]. Minimally invasive alternatives have been explored. Laser ablation, microwave ablation, HIFU, and radiofrequency ablation (RFA) are safe and effective techniques for the treatment of nodular goiter. it is possible to treat small nodules early and enlarge them before surgical intervention is indicated. We have introduced a new method of RFA treatment (2019) in our country. Purpose: To assess the effectiveness of radiofrequency ablation (RFA) for cystic thyroid nodules. Material and Method: This retrospective study was approved by the Research Ethics Committee of the Mongolian National University of Medical Sciences and informed consent was obtained from all patients before RFA. The study was conducted from 9th Jan 2019 to 15th Oct 2021, 485 nodules from 183 patients (M:F=9:174; mean age±SD=46.3±11.4 years) who met the eligibility criteria and provided written informed consent were enrolled at the First Central Hospital of Mongolia. Nodules were assessed pre-treatment and at 1, 3, 6, 12, and 24 months post-treatment. Nodule volume were recorded at each time point.
The primary endpoint was the volume reduction ratio (percentage) at 1, 3, 6, 12, and 24 months follow-up. Results: For the primary outcome of nodule volume reduction, the absolute volume reduction at the 24-month follow-up was 45 (77.6%). Completely destroyed 10 (17.2%), volume increased by 3 (5.2%) (table. 3). The median volume reductions at the 1, 3, 6, 12, and 24-months follow-ups were 34.9%, 61.0%, 74.9%, 83.3% and 74.0% respectively. Median volume statistically decreased by a significant p=0.0001. At 3 months follow up after RFA, the nodules decreased most. All study subjects recovered without sequelae. Therefore, no patient experienced a life-threatening or delayed complication during the follow-up. Conclusion Our study demonstrates that RFA is a safe and effective treatment for cystic thyroid nodules. Advantages of RFA include no surgical scars or general anesthesia, low complication rates, and avoiding lifelong thyroid hormone replacement.

Introduction: Hepatocellular carcinoma incidence and mortality per 100,000 population in Mongolia is the highest in the world. The individual’s genetic factors and new genetic changes are considered an important effect on the origin and development cancer. We aimed to investigate whether p53R72P polymorphisms were associated with the risk of hepatocellular carcinoma in Mongolian patients. Material and Method: p53R72P polymorphisms were evaluated in 80 controls and 38 HCC cases using a PCRrestriction fragment length polymorphism assay. Results: The mean age was 58.5±13.6 years in the case group and 63.2±8.1 years in the control group. Hepatocellular carcinoma is most common in 50-59 (n=14, 36.8%) and 60-69 (n=14, 36.8%) ages. Of the HCC group, 4 (10.8%) were diagnosed with tumor at stage II, 23 (62.2%) at stage III, and 11 (27%) at stage IV.
The results revealed that the heterozygous (Arg/Pro (PR)) genotype of p53R72P increased statistically significant the risk of hepatocellular carcinoma (OR=4.222, 95% CI 1.669-10.684) compared to the wildtype (R/R) genotype. (p=0.002). Moreover, the homozygous (Pro/Pro (P/P)) genotype of p53R72P increased the risk of carcinoma (OR=1.333, 95% CI 0.414-4.299) but not statistically significant. (p=0.63). Heterozygous (Arg/Pro (PR)) genotype of p53R72P in the tumor tissue was associated with a statistically significant (OR=3.3, 95% CI 1.274-8.57) increase in the risk of HCC (p=0.014). Pro/Pro (PP) genotype increased the risk of the carcinoma by 2.4 times (OR=2.44, 95% CI 0.865-6.908), but it was not significant. (p=0.092). Pro/Pro (PP) genotype of p53R72P in the tumor tissue compared to normal tissue of a case group increased the risk of cancer by 1.8 times (OR=1.833, 95% CI 0.472- 7.126), which was not statistically significant (p=0.382). Conclusion Taken together, Heterozygous (Arg/Pro (PR)) genotype of p53R72P increases the risk of hepatocellular carcinoma in Mongolians. Further studies with larger populations are needed to confirm these results.

Background: Headache disorders are most prevalent public-health problem. Worldwide, among the adults 46% suffer from primary headache, where the migraine presents 11% and tension type headache (TTH) presents 25%. Recently, one type of the primary headache, medication overuse headache tends to increase. Nowadays, there is no sufficient study about primary headache in Mongolia. So that, it is necessary to investigate prevalence, clinical type and risk factors of the primary headache. Purpose: To study prevalence and risk factors of primary headache in Mongolia. Materials and Methods: This cross-sectional study was carried out from June to November of 2017. Participants aged 18-65 years old were randomly selected from four provinces and three districts of Ulaanbaatar city. The diagnosis of headache was made using the International Classification of Headache Disorders-3 beta. Statistical analysis was performed on SPSS-23 program. Results: A total of 2043 participants (812 men and 1231 women) were reviewed. The participant’s average age was 38.6±13.4years. 1350 (66.1%) participants reported recurrent headache within the last 1 year. Of the total study population, the prevalence rate of primary headache was 1305 (63.9%). Number of people who suffered from migraine was 494 (24.2%), significantly greater in female than male participants (p=0.0001), with most frequent attacks at age 26-45 years. The risk of migraine associated with sex, education and family history (p=0.001). 592 (29.0%) of participants had TTH, mean age of them was 37.7±5.24, significant high rate in female than men, risk of TTH depends on education and job. The medication overuse headache was diagnosed at 116 (5.7%), 29.4% in men and 70.5% in women with average of 45.6±11.4 and 43±12.7 respectively. Among the participants 38.6% used medications, 28% people had one drug, 8.5% two drugs and 2% used three or more drugs. Use of non-steroid anti-inflammatory drugs (NSAID) made up major percent in headache patients. Increased frequency of medication and multidrug affected to medication overuse headache (p=0.008). Conclusion More than half of studied population had primary headache. Migraine was in 24.2%, TTH in 29.0% of people, and associated with sex, education and family history. Use of non-steroid anti-inflammatory drugs made up major percent in headache patients.