Clinical and Epidemiological Aspects of Late Onset Multiple Sclerosis in East-Azerbaijan, Iran; A Population-Based Study.

BACKGROUND: Late-onset multiple sclerosis (LOMS) is defined as symptoms initiating at an age above 50. Objective: This study aims to determine the clinical and epidemiological aspects of LOMS in East-Azerbaijan province, Iran. METHODS: This population-based study recruited nearly all MS patients to the end of 2020, who were diagnosed at age≥50, by referring to the only local MS registry center. We investigated prevalence, sex, age-of-onset, first clinical presentation, family history, and gap of diagnosis. Also, we compared the disease characteristics between male and female cases. RESULTS: Out of 4905 total cases of MS, 217 cases (4.42%) were LOMS. The mean age of onset was 53.80±3.41 years with a maximum age of 68 years. The most common age group of the patients was 50 to 55 years (69.1%). The frequency by sex of LOMS in females (150) was greater than males (67). Positive family history was seen in 6.17%, and in 41% of the patients, the disease was diagnosed in a timely manner. Early symptoms were motor (31.3%), sensory (24.8%), optic neuritis (23%), cerebellar symptoms (13.8%), and brainstem symptoms (6.9%). The first presentation of the disease was different between male and female cases (P-value<0.01). Motor symptoms were the most prevalent first clinical presentation in female cases (37.6%), while in male cases, cerebellar symptoms (25.8%) were the most common. CONCLUSION: LOMS is not a rare condition. Increasing knowledge in the diagnosis, as well as increasing awareness of the disease in the general population, leads to early diagnosis of LOMS and prevention of consequences.

Age and sex adjusted prevalence and annual incidence of multiple sclerosis in East-Azerbaijan, Iran.

BACKGROUND: Incidence and prevalence of multiple sclerosis (MS) is postulated to be rising in recent decades. Therefore, updating and completing the information of patients is essential, especially in high population areas. East-Azerbaijan is the largest and most populous province in the northwest of Iran. This study aimed to determine the prevalence and annual incidence of MS from 2008 to 2017 in East-Azerbaijan. METHODS: We evaluated the data of all patients who had registered at the MS center in the university hospital. The data include nearly all MS patients in the East-Azerbaijan region, because it is the only referral site in the area. All of the reported rates were calculated in 100,000 of the total population. RESULTS: By the end of 2017, the number of MS patients was 2995 (residing in the, with 769 (25.67%) men and 2226 (74.32%) women. The prevalence rate was 75.72/100,000 (95 % CI: 73.06-78.48), 38.2 in men (95% CI: 35.5-41.0), and 114.61 for women (95% CI: 109.9-119.4), with a female to male (F/M) ratio of 3:1. The mean annual incidence rate was 7.63/100,000 (95% CI: 5.6-9.3), and this rate was higher in women than men. During the nine years, the incidence rate increased. The patients' mean age was 32.33 ± 8.92, with a peak prevalence in 25-29 years for both genders. In this study, 13.9% of patients had a positive MS family history. CONCLUSIONS: This study showed a high prevalence of MS in the region. There is a significant increase in the incidence of MS during the nine years in East-Azerbaijan. The increment of incidence was more prominent in women. Also, considering the increasing incidence rate, it is concluded that the risk of MS is increasing in this region.