The epidemiology series of brain-related disorders in Mongolia: nationwide registry-based epidemiological study on CNS tumours in Mongolia, 2015-2019.

No epidemiological study on central nervous system tumours is available for Mongolia. The aim of this study was to determine the incidence, mortality and survival of people diagnosed with central nervous system tumours in Mongolia. It reports cancer data for the entire population (3.3 million) during the period between 2015 and 2019. Data was obtained from the National Cancer Registry of Mongolia. Diagnosis of tumours was established according to the diagnostic criteria of the International Classification of Diseases-10 (ICD-10). Incidence and mortality rates were calculated as mean annual numbers per 100,000 population. Age-standardized incidence and age-standardized mortality rates were calculated from age-specific rates by weighting directly from the World Standard Population. The three-year survival from 2015 through 2017 was calculated between treatment types by the Kaplan-Meier survival analysis. It found 515 (adults: 83 %; children: 17%) newly diagnosed central nervous system tumour cases over the five year period. The national age-standardized incidence of central nervous system tumours for the entire population was 3.7 per 100,000. The rate was higher for males than females (4.2 versus 3.4 per 100,000, respectively). Only 23% of the diagnosed cases were confirmed histologically. The most common tumour was glioma (57.6% of histologically verified tumours). In children (age 0-19 years) the age-specified incidence rate of tumours was 1.4 per 100,000. Geographically, the age-standardized incidences of the Eastern region were higher than the country average rates for both genders. During the period, 381 deaths were registered with an age-standardized mortality rate of 3.0 per 100,000 population. Furthermore, the overall three-year survival rate was 40.6% (out of 283 patients, 115 survived). The five-year prevalence of tumours was 183 and the mean per 100,000 population was 5.5. In conclusion, the data from the National Cancer Registry indicate that the incidence and survival rates of central nervous system tumours in Mongolia are relatively low. The most common location of central nervous system tumours was the brain. Glioma was the most common tumour among histologically confirmed cases. Despite the limitations, data from this study should provide information for national health policy and health care assessment. To improve the diagnosis, prognosis and treatment of central nervous system tumours, expansion of the cancer registry through collecting data on non-malignant tumours, increasing the rate of histological verification, conducting studies on cancer epidemiology and the introduction of advanced treatment technologies for central nervous system tumours are recommended.

Validation of the abbreviated version of the World Health Organization Quality of Life in Mongolia: a population-based cross-sectional study among adults in Ulaanbaatar.

There is currently no validated tool to measure the quality of life (QOL) in the Mongolian language. This study aimed to validate the Mongolian version of the World Health Organization Quality of Life - Brief (WHOQOL-BREF) questionnaire for the general population of Mongolia. The subjects were 301 adults aged 18-65 years selected randomly by a computer from 30 centers in 8 districts of Ulaanbaatar, Mongolia, in 2020. Reliability was measured using Cronbach's α and intraclass correlation coefficients. Convergent, discriminant, and construct validities were examined using exploratory and confirmatory factor analyses for a four-domain factor structure. Among the participants, 56.1% were women, 32.9% held a bachelor's degree or higher, 48.8% were employed, and 61.8% were married. The overall Cronbach's α coefficient of the WHOQOL-BREF questionnaire was 0.804. Correlations between the component scores of the WHOQOL-BREF ranged from 0.581-0.822. All items showed higher item-total correlations with their corresponding domains than with other domains, except the mobility item from the physical domain. Discriminative validity was evident in physical and psychological domains. Exploratory and confirmatory factor analyses revealed a four-factorial structure consisting of 24 items that provided an acceptable fit to the data (RMSEA=0.084; CFI=0.860). In conclusion, the Mongolian version of the WHOQOL-BREF demonstrated evidence of good reliability and validity for assessing QOL in the general population of Mongolia. These findings indicate that it allows the comparison of QOL of adults in Mongolia with those in other countries.

Quality of life in the general population of Mongolia: Normative data on WHOQOL-BREF.

No data on the quality of life (QOL) of the general population are available for Mongolia. This study aimed to determine normative data on the World Health Organization Quality of Life-Brief Version (WHOQOL-BREF) in the general population of Mongolia. This nationwide, population-based, cross-sectional study was conducted in 48 sampling centers across Mongolia in 2020. We used the WHOQOL-BREF and the Hospital Anxiety and Depression Scale (HADS) in our study and evaluated their associations with vital signs, body measurements, and lifestyle determinants. A total of 714 participants (261 men and 453 women) with a mean (standard deviation) age of 40.7 (13.2) years were recruited. The mean scores of WHOQOL-BREF subscales were 61.5 for physical health, 73.5 for psychological health, 70.1 for social relationship, and 67.2 for environmental health domains. The prevalence of poor QOL was 16.9% among the participants. Participants living in an apartment in urban areas with high HADS scores had a low QOL. All domains of WHOQOL-BREF were inversely correlated with anxiety score (r = -0.353 - -0.206, p < 0.001) and depression scores (r = -0.335 - -0.156, p < 0.001). Physical health was predicted by residency location, anxiety, and depression (R2 = 0.200, p < 0.001); psychological health by anxiety and depression (R2 = 0.203, p < 0.001); social relationship by residency location, age group, anxiety and depression (R2 = 0.116, p < 0.001); and environmental health by employment, anxiety, and depression (R2 = 0.117, p < 0.001). This is the first report on normative data on the QOL in the general population of Mongolia. Physical health was low compared with that determined using international data. Poor QOL was observed among those with mental health issues living in the urban areas.

Effect of using a titanium washer on the removal torque of an abutment screw in the external connection type of dental implant.

PURPOSE: The aim of this study was to determine the effect of using a washer on the removal torque of an abutment screw in the external connection type of dental implant and abutment complex. MATERIALS AND METHODS: Four experimental groups with titanium washers of different types (CP titanium or Ti6Al4V titanium alloy) and thicknesses (1.0 or 2.0 mm) included between the abutment and external connection type of implant were investigated. No washer was applied in the control group. The removal torque was measured with a resolution of 0.1 Ncm. One-way analysis of variance (α = 0.05) and Scheffé's post hoc test were used for statistical analysis. RESULTS: The removal torque was higher in all the groups with a washer than in the control group (α = 0.05), higher with a CP titanium washer than with a titanium alloy washer of the same thickness, and higher with a 2.0-mm-thick washer than with a 1.0-mm-thick washer (α = 0.05). CONCLUSIONS: Inclusion of a washer between the titanium screw and the abutment seems to increase the removal torque. A 2.0-mm-thick CP titanium washer might provide the largest increase in the removal torque.

Improvement of osteogenic potential of biphasic calcium phosphate bone substitute coated with synthetic cell binding peptide sequences.

PURPOSE: The aim of this study was to evaluate the improvement of osteogenic potential of biphasic calcium phosphate (BCP) bone substitute coated with synthetic cell-binding peptide sequences in a standardized rabbit sinus model. METHODS: Standardized 6-mm diameter defects were created bilaterally on the maxillary sinus of ten male New Zealand white rabbits, receiving BCP bone substitute coated with synthetic cell binding peptide sequences on one side (experimental group) and BCP bone substitute without coating (control group) on the other side. Histologic and histomorphometric analysis of bone formation was carried out after a healing period of 4 or 8 weeks. RESULTS: Histological analysis revealed signs of new bone formation in both experimental groups (4- and 8-week healing groups) with a statistically significant increase in bone formation in the 4-week healing group compared to the control group. However, no statistically significant difference in bone formation was found between the 8-week healing group and the control group. CONCLUSIONS: This study found that BCP bone substitute coated with synthetic cell-binding peptide sequences enhanced osteoinductive potential in a standardized rabbit sinus model and its effectiveness was greater in the 4-week healing group than in the 8-week healing group.

Improvement of osteogenic potential of biphasic calcium phosphate bone substitute coated with two concentrations of expressed recombinant human bone morphogenetic protein 2.

PURPOSE: The aim of this study was to determine whether biphasic calcium phosphate (BCP) bone substitute with two different concentrations of Escherichia coli-expressed recombinant human bone morphogenetic protein 2 (ErhBMP-2) enhances new bone formation in a standardized rabbit sinus model and to evaluate the concentration-dependent effect of ErhBMP-2. METHODS: Standardized, 6-mm diameter defects were made bilaterally on the maxillary sinus of 20 male New Zealand white rabbits. Following removal of the circular bony windows and reflection of the sinus membrane, BCP bone substitute without coating (control group) was applied into one defect and BCP bone substitute coated with ErhBMP-2 (experimental group) was applied into the other defect for each rabbit. The experimental group was divided into 2 subgroups according to the concentration of ErhBMP-2 (0.05 and 0.5 mg/mL). The animals were allowed to heal for either 4 or 8 weeks and sections of the augmented sinus and surrounding bone were analyzed by microcomputed tomography and histologically. RESULTS: Histologic analysis revealed signs of new bone formation in both the control and experimental groups with a statistically significant increase in bone formation in experimental group 1 (0.05 mg/mL ErhBMP-2 coating) after a 4-week healing period. However, no statistically significant difference was found between experimental group 1 and experimental group 2 (0.5 mg/mL ErhBMP-2 coating) in osteoinductive potential (P<0.05). CONCLUSIONS: ErhBMP-2 administered using a BCP matrix significantly enhanced osteoinductive potential in a standardized rabbit sinus model. A concentration-dependent response was not found in the present study.

Investigation of bone formation using calcium phosphate glass cement in beagle dogs.

PURPOSE: Among available biomaterials, bioceramics have drawn special interest due to their bioactivity and the possibility of tailoring their composition. The degradation rate and formulation of bioceramics can be altered to mimic the compositions of the mineral phase of bone. The aim of this study was to investigate the bone formation effect of amorphous calcium phosphate glass cement (CPGC) synthesized by a melting and quenching process. METHODS: In five male beagle dogs, 4 x 4 mm 1-wall intrabony defects were created bilaterally at the mesial or distal aspect of the mandibular second and fourth premolars. Each of the four defects was divided according to graft materials: CPGC with collagen membrane (CM), biphasic calcium phosphate (BCP) with CM, CM alone, or a surgical flap operation only. The dogs were sacrificed 8 weeks post-surgery, and block sections of the defects were collected for histologic and histometric analysis. RESULTS: There were significant differences in bone formation and cementum regeneration between the experimental and control groups. In particular, the CPGC and BCP groups showed greater bone formation than the CM and control groups. CONCLUSIONS: In conclusion, CPGC was replaced rapidly with an abundant volume of new bone; CPGC also contributed slightly to regeneration of the periodontal apparatus.