Here Comes the Sun, Maybe: High-Dose Vitamin D Possibly Beneficial in MS
Three environmental factors appear to increase the risk of multiple sclerosis or exacerbate its course.
- Early infection with Epstein-Barr virus.
- Cigarette smoking.
- Vitamin D deficiency (a factor that may explain the observed relationship between MS risk and residence in sunlight-deficient Northern latitudes).
Whether vitamin D supplementation favorably alters outcomes in MS was recently assessed in a randomized early-phase study of 49 patients.* Results of the open-label trial, which was conducted in Canada, were published last week in an advanced, online issue of Neurology.
Level-raising doses of vitamin D (up to 40,000 IU daily), along with supplemental calcium, appeared to reduce the number of relapses during the 52-week study and reduce the proliferation of proinflammatory T cells—both secondary outcomes. High-dose vitamin D did not cause hypercalcemia, persistent hypercalciuria, or nephrolithiasis and appeared to be well tolerated (the primary outcomes). "No significant" adverse events were observed, despite the fact that the mean level of 25(OH)D peaked at 413 nmol/L, which is well above recognized "toxic" levels (eg, 220 nmol/L).
Given the unblinded design of the trial, the favorable clinical outcomes can only be categorized as class level 4 evidence—in other words, data from an observational study that did not have an adequate control group.** The authors indicate that a multicenter, phase 2 proof-of-concept trial, incorporating clinical and MR outcomes, is currently underway.
The NIH database (clinicaltrials.gov) currently lists 3 trials that are assessing vitamin D supplementation in MS (the Canadian phase 2 study is evidently not registered yet).
A phase 4 Israeli trial of high- and low-dose vitamin D. The Merck Serono-supported study will assess the immunomodulatory effects of vitamin D supplementation on interferon-beta reactions.
A phase 4 Norwegian study of changes in bone-mineral density.
A phase 1 pilot study at Hopkins, which will assess the safety and immunomodulatory effects of low-dose vitamin D.
25(OH)D = 25-hydroxyvitamin D. (Measuring 25(OH)D is the standard for assessing the body's vitamin D status.)
* Forty-five patients had relapsing-remitting disease.
** Patients in the trial's control group were allowed to take vitamin D and calcium at their discretion.
