Changing patterns of multiple sclerosis in Korea: Toward a more baseline MRI lesions and intrathecal humoral immune responses

Background: The environmental risks of multiple sclerosis (MS), including adolescent obesity and vitamin D deficiency, are increasing in Korea. We aimed to determine whether the patterns and/or severity of MS in Korea can change according to the year of birth or disease onset. Methods: Two hundred and sixty-six patients with adult-onset MS, including 164 with an available baseline magnetic resonance imaging (MRI), were retrospectively included from 17 nationwide referral hospitals in Korea. The demographics, MRI T2 lesion burden at disease onset, cerebrospinal fluid markers, and prognosis were assessed. Results: The birth year, time from disease onset to first MRI, and female sex were associated with a higher number of baseline MRI T2 lesions. The birth year was also associated with the presence of oligoclonal band in the cerebrospinal fluid and high immunoglobin G index. An increased female/male ratio was observed among those with a more recent year of birth and/or disease onset. Conclusions: In Korea, the disease pattern of adult-onset MS may be changing toward a more baseline T2 MRI lesions, intrathecal humoral immune responses, and also higher female ratio.