Two hundred and forty patients with multiple sclerosis who met the study criteria will be
enrolled in this randomized double blind placebo-controlled clinical trial.
They will randomly assigned to placebo or vitamin D treatment group. The total time of study
is 52 weeks and the vitamin D group will be treated by weekly 50000 International unit(IU)
vitamin D, while the other group will receive weekly placebo. The annual relapse rate and
EDSS will be compared at baseline, month 6 and 12.