Vitamin D and MS disease activity

21 June 2012

Author: MS Trust

Three new studies suggest an association between low levels of vitamin D and MS disease activity but also highlight the problems of interpreting findings in this type of research.

The results of the studies appear in the online version of the journal Neurology.

A Norwegian study of 88 people found that increasing vitamin D levels by 10 nmol/L was associated with a reduction of a little more than 10% in the likelihood of new lesions as visible on MRI scans. This effect was apparent in the six months prior to starting treatment with beta interferon but not in the 18 months after treatment had started.

An Australian study of 178 people found a similar increase in vitamin D levels reduced the relapse rate by 10%, but only saw this effect in people on beta interferon.

A Dutch study of 73 people found doubling vitamin D levels reduced risk of relapse by 27%.

The editorial accompanying these results draws attention to the difficulties of interpreting these results. The trials do not give enough information to indicate whether the effects seen are caused by vitamin D levels, the relatively small number of people in trials and the fluctuating levels of vitamin D throughout the year due to season, time spent outdoors and use of sun block or other protection.

The editorial also raises the unanswered question of whether the nature of MS means that what are adequate vitamin D levels for the general population might be too low for people with MS.