Effects of air pollution and seasons on health-related quality of life of Mongolian adults living in Ulaanbaatar: cross-sectional studies.

BACKGROUND: Ulaanbaatar, Mongolia, is known as severely air-polluted city in the world due to increased coal consumption in the cold season. The health effects of air pollution in Mongolia such as mortality, morbidity and symptoms have been previously reported. However, the concept of health-related quality of life (HR-QoL), which refers to the individual's perception of well-being, should also be included as an adverse health outcome of air pollution. METHODS: Surveys on the Mongolian people living in Ulaanbaatar were performed in the warm and cold seasons. Self-completed questionnaires on the subjects' HR-QoL, data from health checkups and pulmonary function tests by respiratory specialists were collected for Mongolian adults aged 40-79 years (n = 666). Ambient PM2.5 and PM10 were concurrently sampled and the components were analyzed to estimate the source of air pollution. RESULTS: In logistic regression analyses, respiratory symptoms and smoke-rich fuels were associated with reduced HR-QoL (> 50th percentile vs. ≤ 50th percentile). PM 2.5 levels were much higher in the cold season (median 86.4 µg/m3 (IQR: 58.7-121.0)) than in the warm season (12.2 µg/m3 (8.9-21.2). The receptor model revealed that the high PM2.5 concentration in the cold season could be attributed to solid fuel combustion. The difference in HR-QoL between subjects with and without ventilatory impairment was assessed after the stratification of the subjects by season and household fuel type. There were no significant differences in HR-QoL between subjects with and without ventilatory impairment regardless of household fuel type in the warm season. In contrast, subjects with ventilatory impairment who used smoke-rich fuel in the cold season had a significantly lower HR-QoL. CONCLUSIONS: Our study showed that air pollution in Ulaanbaatar worsened in the cold season and was estimated to be contributed by solid fuel combustion. Various aspects of HR-QoL in subjects with ventilatory impairment using smoke-rich fuels deteriorated only in the cold season while those with normal lung function did not. These results suggest that countermeasures or interventions by the policymakers to reduce coal usage would improve HR-QoL of the residents of Ulaanbaatar, especially for those with ventilatory impairment in the winter months.

Prevalence and risk factors of airflow limitation in a Mongolian population in Ulaanbaatar: Cross-sectional studies.

The burden of chronic obstructive pulmonary disease (COPD) is expected to increase in the coming decades. In Ulaanbaatar, Mongolia, air pollution, which has been suggested to correlate with COPD, is a growing concern. However, the COPD prevalence in Ulaanbaatar is currently unknown. This study aims to estimate the prevalence of airflow limitation and investigate the association between airflow limitation and putative risk factors in the Mongolian population. Five cross-sectional studies were carried out in Ulaanbaatar. Administration of a self-completed questionnaire, body measurements, and medical examination including spirometry were performed in 746 subjects aged 40 to 79 years living in Ulaanbaatar. The age- and sex-standardized prevalence of airflow limitation in Ulaanbaatar varied widely from 4.0 to 10.9% depending on the criteria for asthma. Age, body mass index (BMI), and smoking habit were independent predictors for airflow limitation while residential area and household fuel type were not significant. In conclusion, prevalence of putative COPD was 10.0% when subjects with physician-diagnosed asthma were excluded from COPD. Older age, lower BMI, and current smoking status were putative risk factors for airflow limitation. This prevalence was consistent with reports from Asian countries.

Effects of air pollution and seasonality on the respiratory symptoms and health-related quality of life (HR-QoL) of outpatients with chronic respiratory disease in Ulaanbaatar: pilot study for the comparison of the cold and warm seasons.

BACKGROUND: This study was performed to investigate the effects of air pollution and seasonality on the respiratory symptoms and health-related quality of life (HR-QoL) of outpatients with respiratory diseases in Ulaanbaatar, Mongolia. Subjects were outpatients who visited the hospital with chronic obstructive pulmonary diseases (COPD) or bronchial asthma (BA) in March. Their symptoms and HR-QoL were evaluated using a questionnaire including the SF-36v2 and COOP/WONCA charts in March, May and July. PM2.5 was sampled in March and July in Ulaanbaatar, and its composition was analyzed. RESULTS: Patients with COPD or BA showed higher prevalence of respiratory symptoms than the control subjects in each month. For HR-QoL, all subscales worsened in the patients than in the control group in March. Although the HR-QoL of the COPD and control groups were not significantly changed through the surveys, some subscales of the BA group showed remarkable improvement in July as compared to March. Daily means of PM2.5 in March were significantly higher than those in July. Carbon and ionic component concentrations, except for magnesium and calcium ions, were significantly higher in March than July. Mass concentrations of some metallic components were also significantly higher in March than July. The percentage of nitrate ion in PM2.5 was significantly higher in March when compared to that in July. CONCLUSIONS: These results suggested that the symptoms in the COPD and BA groups were caused by the disease, and the association with air pollution or seasonality remained unclear. However, the effects of air pollution and seasonality on the HR-QoL were significant in the patients with BA.

Validation of the Mongolian version of the SF-36v2 questionnaire for health status assessment of Mongolian adults.

BACKGROUND: Ulaanbaatar, Mongolia, is one of the world's worst air-polluted cities, but effects of this air pollution on the population health status have not yet been evaluated. Therefore, we developed a Mongolian version of the SF-36v2 questionnaire to investigate the health status of Mongolian population. METHODS: Health checkups were conducted in Ulaanbaatar and the health status was measured using a Mongolian translated version of the SF-36v2 questionnaire. The reliability and validity of the Mongolian SF-36v2 questionnaire, and the relationship between health status and respiratory condition were examined. RESULTS: Factor analysis of the Mongolian SF-36v2 questionnaire showed that the "Role-physical" and "Role-emotional" were classified into a single subscale. The "Mental health" and "Vitality" were each divided into two subscales. Cronbach's alpha and intraclass correlation coefficient (ICC) for reproducibility were >0.7, except for "General health perceptions" (Cronbach's alpha and ICC < 0.7), "Social functioning" (Cronbach's alpha < 0.7), and "Vitality" (ICC < 0.7). The SF-36v2 subscales and the corresponding items of the COOP/WONCA charts were correlated, and subjects with respiratory symptoms showed lower SF-36v2 scores compared to normal subjects, suggesting external validity. Subjects with respiratory symptoms showed significantly lower scores for the majority of the SF-36v2 subscales than those with normal lung function. In subjects with combined ventilatory impairment, "Physical functioning", "Role-physical", "Bodily pain", and "Vitality" scores were significantly lower than those with normal lung function. CONCLUSIONS: The Mongolian version of the SF-36v2 questionnaire provides substantial reliability and validity, and is useful for evaluating the health status of Mongolian adults with ventilatory impairment. Health status measured by SF-36v2 was significantly aggravated by combined ventilatory impairment when compared with normal lung function.