Background: The average age at menarche (AAM) among girls is influenced by various factors, including the socioeconomic status of the country, geographical location, and anthropometric characteristics. In Mongolia, limited research has been conducted on this topic Aim: This study aimed to compare the mean age at menarche among girls living in Bayanzürkh District of Ulaanbaatar and those in Uvs Province. Materials and Methods: A cross-sectional study was conducted between April and June 2025. The study participants included schoolgirls aged 8 years and older from general education schools located in Bayanzürkh District and Uvs Province. Statistical analyses were performed using R version 4.5.1 (RStudio 2025.05.1-513) Results: A total of 486 girls participated in the study. The mean age at menarche among the participants was 12.23±1.29 years. The mean age at menarche among girls aged 8–18 years in Bayanzürkh District was 11.84±1.19 years, while that among girls aged 8–18 years in Uvs Province was 12.97±1.15 years. Thus, girls in Bayanzürkh District experienced menarche 1.13 years earlier on average than those in Uvs Province. The difference in mean AAM between urban (Ulaanbaatar) and rural (Uvs Province) girls was statistically significant (p<0.0001). Conclusion The mean age at menarche among girls residing in Bayanzürkh District was significantly lower than that of girls living in Uvs Province, indicating a tendency toward earlier onset of menarche in urban areas.

Background: In the 21st century, as a health problem of increased nonspecific low back pain, it is becoming one of the risk factors for leaving the occupation. 90-95%of the total waist back pain is the nonspecific back pain. Overloading of the spine because nurses are in a compressed position to work with the patient is a high risk for back pain. This study aim of our study was relationship between nonspecific low back pain and workplace among nurses in tertiary care first, second and third hospitals in Mongolia. Methods: This study used a descriptive correlational design to relationship between nonspecific low back pain and physical activity among nurses. We collected data from 133 registered nurses, randomly selected and working in three general public tertiary care hospitals in the capital city of Ulaanbaatar of Mongolia. An instrument used were the Standardized Nordic Musculoskeletal Questionnaire (SNMQ). Data were analysed using descriptive statistics and correlation coefficient test. Results: Sixty two percent (82) were perceived a low back pain. The ratio of nurses with non-specific low back pain is 82 / 51=0.62 (odds). In other hand, one in two nurses were perceived non-specific low back pain, which is high prevalence. The relationship between nurses’ low back pain and workplace, r=0.25 has a direct weak correlation and is not statistically significant (p=0.15). Conclusions The results suggest that effective preventive measures form nonspecific low back pain for nurses. In the future, it is important to protect the health of existing nurses and keep them in the workplace.