High-dose vitamin D does not reduce MS disease activity

High-dose vitamin D does not lessen the risk of disease activity for people with multiple sclerosis (MS), data from a new clinical trial indicates.

Patients aged 18 to 50 with relapsing remitting MS were enrolled at US neurology clinics between 2012 and 2019. They had to have an Expanded Disability Status Scale of less than four and have had no more than 1000 IU of supplemental vitamin D on average daily for the previous 90 days. All were being treated with glatiramer acetate (Copaxone).

They also had to have blood levels of vitamin D of 15 ng/mL or more, because it is unethical to enrol people who have a deficiency in a clinical trial in which they may be given a low dose.

Patients were randomly assigned low (600 IU) or high (5,000 IU) doses a day for approximately two years.

Researchers said the low dose was effectively a placebo as they didn’t expect to see any kind of change in MS activity with this amount.

In the patients receiving the high dose, average blood vitamin D levels rose substantially, and in the low-dose group, levels were generally stable.

Researchers made comparisons between the rates of radiologically-measured change in MS, such as active inflammatory lesions, new and emerging lesions, and rates of brain shrinkage.

There were no statistically significant differences in any of these measures between the two groups, leading the researchers to conclude that “high dose vitamin D3 supplementation, as add-on to [glatiramer acetate] therapy, does not reduce imaging measures of disease activity in established RRMS.”

Although this trial tested vitamin D alongside glatiramer acetate specifically, the researchers said they’d expect the results to be similar with any disease-modifying therapy.

The results were presented at the Americas Committee for Treatment and Research in Multiple Sclerosis (ACTRIMS) Forum, Feb. 23-25 in San Diego.