This study from Australia looked at the relationship between gender differences in the incidence of multiple sclerosis relapses as well as the relationship between sex and primary progressive disease course on a large international observatory cohort: the MSBase registry. The study cohort included 11,570 subjects with RRMS and 881 people with primary progressive MS. The researchers recorded 48,362 relapses among the relapse onset patients which included 82,552 patient-years. They found that females had a higher relapse frequency compared to males by 17.7%. Within the first five years, the female-to-male ratio increased from 2.3:1 to 3.3:1 in patients with 0 versus ≥4 relapses per year. The female-to-male ratio in people with relapse-onset MS and zero relapses in any given year was double that of the people with PPMS. Interestingly, the researchers found an inverse relationship between relapse frequency and either disease duration or age. Of these two factors, age was more closely related to a decline in relapse incidence than disease duration. The higher relapse frequency seen in females compared to males does not explain the lower female-to male sex ratio in PPMS.
Authors: Kalincik T, Vivek V
Source: Brain. 2013 Oct 18. [Epub ahead of print]
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