Seasonal Variation of Multiple Sclerosis Relapses in Oman

• Published in: Multiple sclerosis and related disorders 2023-12, Vol.80, p.105229, Article 105229
• Main Authors: Al-Asmi, Abdullah, Al-Shibli, Rashid, Al-Amri, Amira, Al-Lawati, Meetham, Al-Hashmi, Lubna, Al-Yahmadi, Jihad
• Format: Article
• Language: English
• ISSN: 2211-0348
• DOI: 10.1016/j.msard.2023.105229

Multiple sclerosis (MS) is a progressive inflammatory autoimmune central nervous system disease. Relapsing-remitting multiple sclerosis (RMS) is the most common type of MS. The seasonal variation of MS relapses has been reported in various studies and differs across populations. Some studies reported increased relapses in winter, while others reported them in summer or spring. Multiple factors may affect the frequency of relapses and the progression of the disease, such as sun exposure (low vitamin D), temperature, humidity, and some infections. This is a retrospective study where demographic and clinical data of all Omani MS patients followed at Sultan Qaboos University Hospital (SQUH) from 2007 to 2022 were reviewed using the Hospital Information System. Weather data was obtained from the Research and Development Department of the Directorate General of Meteorology of Oman. Parametric analysis was conducted to compare the distribution of relapses across months and seasons. Chi-square test, independent T-test, and ANOVA were used to determine the statistical significance. Pie charts, bar charts, and cross-tabulations were used to represent the data visually. A total of 183 MS patients were included, of which 125 (68.30%) were females. Overall 508 relapses were recorded. During the winter season, females showed a higher number of relapses compared to males. The winter season was observed to have the highest annual mean relapses (AMR) of 8.3; however, no statistical significance was found. Most of the relapses were in January. No correlation between MS relapses and climatic parameters were found. Although winter had the most MS relapses, no statistical significance was found in seasonal variation or any relation to weather parameters in MS relapses among Omani MS patients during the study period. Further studies are needed to understand how environmental factors influence MS relapses and disease progression.