Multiple Sclerosis in Mongolia; the First Study Exploring Predictors of Disability and Depression in Mongolian MS Patients

Mongolia is located at 45° north latitude in the center of the Asian continent, and about 80% of the territory is at 1000 m above sea level. Epidemiologically, multiple sclerosis (MS) has not been investigated in Mongolia, although there have been a few MS case reports. We investigated the characteristics of MS in Mongolia for the first time, focusing on the association between MS-related parameters and depression levels. We initiated cross-sectional analyses, using data from 27 MS patients aged 20 to 60 years in Ulaanbaatar, Mongolia. The patients completed a questionnaire on their lifestyles and clinical information. We classified the MS patients on the basis of disability levels using the expanded disability status scale (EDSS) scores: 11.1% mild disability and 88.9% moderate to severe disability (median EDSS score, 5.5). We also classified the patients on the basis of depression levels using the 9-item patient health questionnaire (PHQ-9) scores: 44.4% mild depression, 40.7% moderate depression, and 14.8% severe depression (mean PHQ-9's score, 9.96 ± 5.05). We used multivariate logistical regression analyses to identify predictors of EDSS or PHQ-9 scores. Disability levels were associated with vision and balance problems. Depression levels were associated with corticosteroid treatment; no patients were treated with disease-modifying drugs (DMDs). The odds ratios for disease onset age and treatment duration were associated with EDSS scores. In conclusion, MS onset age and treatment duration were independent predicting factors influencing the level of disability. Appropriate DMD treatment would lower the disability and depression levels.