A study of Iranian patients with early-onset multiple sclerosis (MS) found women to be in the majority, optic neuritis to be the most common first disease symptom, and relapsing-remitting MS the most frequent disease course.
The epidemiology of early-onset MS (typically, MS diagnosed before age 16; age 18 was the benchmark for this study) has not been extensively studied in the Middle East, leading researchers at Tehran University of Medical Sciences to characterize early-onset patients referred to the country’s MS society between 2005–15. (Typically, MS with first disease presentations occurring before age 16 is considered early onset; age 18 was the benchmark for this study.)
Results were published in the study “Early-Onset Multiple Sclerosis: Reports of 300 Patients from Iran” in the Journal of Pediatric Neurosciences.
Age-of-onset can be between 10 and 60 years old for MS, but most cases are reported the ages of 20 and 30 years. Disease that strikes in childhood or adolescence has an estimated incidence rate of only 5 percent.
In total, 300 MS patients were included in the study, and data collected regarding gender, age at onset, first symptoms, time interval between first presentation and diagnosis, clinical course, MS family history, and smoking history.
Most (78%) early-onset patients were women, which is consistent with studies showing that the female-to-male ratio is higher when MS that strikes early in life.
Patient ages ranged from 4 to 18, but most (75.3%) were adolescents between 15 and 18 years old. The average age of disease onset was 15.6.
Time between first symptoms being experienced and disease diagnosis ranged between 0.1 month and 144 months (12 years), with a mean of 16.8 months.
The most common symptom at disease onset affected the eyes — optic neuritis, an inflammation of the optic nerve, was reported in in 46.7% of patients. The remainder reported experiencing either sensory symptoms (27.3%) or multiple symptoms at onset (10%). This finding was in contrast to previous studies in early-onset MS, which reported multiple disease symptoms (polysymptomatic presentation) being most common in these patients.
Concerning family history, 16.7% of patients had a positive MS family history, and 63.3% came from families whose parents did not smoke.
MS is known to have four types of clinical course. Among patients in Iran, as elsewhere, relapsing-remitting MS (RRMS) was the most common clinical disease course, found in 80% of the patients; 12.67% experienced a secondary progressive MS (SPMS) course, 4% a primary progressive course, and a progressive relapsing course was observed in 3.33% of patients.
These results are in line with previous reports, in which RRMS is the most common form of disease progression, followed by SPMS.
The team concluded: “In our study, the EOMS [early-onset MS] was higher in females. Despite the earlier studies, it was found that the polysymptomatic onset was not very common. Optic neuritis was the most initial presentation and RRMS was the most frequent course.”