The gender differences in this type of the disease seem to vary by age group. In the largest studies done so far, scientists kept tabs on hundreds of men and women with primary progressive MS for decades. They found:
- Under age 30, equal numbers of men and women had the condition.
- More women than men got it after age 45.
- 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.