Primary Progressive MS and Gender
The 'Equal Opportunity' MS continued...
Among the patterns of illness in multiple sclerosis, primary progressive MS is the most elusive. Because it's slow and insidious, it's difficult to study (requiring long-term, expensive research). For decades, primary progressive MS remained shrouded in mystery.
Recent studies, however, show that primary progressive MS is indeed different. In the largest studies done so far, hundreds of men and women with primary progressive MS were followed for decades. The results were surprising:
- Under age 30, equal numbers of men and women were affected.
- Among people developing MS later -- older than 45 -- women still predominated.
- Almost two women for each man were diagnosed with primary progressive MS after age 50 -- still short of the rates in other forms of MS.
When it comes to disease severity, primary progressive MS is also unique. MS in men is usually more severe than in women. However, large studies of primary progressive MS showed:
- Early on, men and women had equal disease severity and rates of progression.
- After about 20 years of living with primary progressive MS, men's disease finally began to "outrun" the women's in severity.
Why the differences? At this point, there are more questions than answers. As in other forms of MS, sex hormones may well be involved. There are clues in the chemistry and the MRI scans of the brains of people with primary progressive MS. But research into this mysterious form of multiple sclerosis is challenging, and is only beginning.