The results of three independent studies published in the journal Neurology suggest that higher levels of vitamin D may reduce disease activity in people with MS. Two of these studies showed conflicting results on a possible interaction between vitamin D levels and treatment with interferon beta. These studies add to the rapidly increasing evidence that vitamin D may play a beneficial role in MS. An accompanying editorial suggests that, although there is not enough evidence to recommend high doses of vitamin D for people with MS, ensuring that people with MS have sufficient year-round levels of vitamin D should be part of routine care.
Background: A number of genetic and environmental factors
influence whether a person will get MS. These factors may also impact the severity of the disease. Research is increasingly pointing to a reduced level of vitamin D in the blood as a risk factor for developing MS. In lab mice, vitamin D can reduce the effects of EAE, an MS-like disease, and growing evidence suggests it is time to test whether vitamin D can provide benefits to people who have MS.
Tessel Runia, MD (Erasmus MC, Rotterdam, the Netherlands) and colleagues asked if vitamin D is beneficial during the clinical course of MS. They followed 73 people with relapsing-remitting MS by measuring vitamin D in blood samples every 8 weeks for an average of 1.7 years. The risk of disease worsening decreased when blood vitamin D levels were high. People whose vitamin D levels were considered “low” (less than 50 nmol/L) were twice as likely to experience a relapse as those whose vitamin D level was considered “high” (greater than 100 nmol/L), an association that persisted during all seasons. The effect of vitamin D on exacerbations was not affected by interferon beta use in this group of participants. (Neurology 2012 79:261-266)
Kristin Løken-Amsrud, MD (Innlander Hospital Trust, Lillehammer, Norway) and colleagues studied a group of 88 untreated people with relapsing-remitting MS by collecting 12 MRI scans and nine vitamin D measurements per person over 24 months. People with higher vitamin D levels had a reduced chance of developing new MRI-detected brain lesions. After beginning interferon beta treatment, there was no association between vitamin D levels and disease activity. (Neurology 2012;79:267-273)
Niall Stewart, PhD (University of Tasmania) and colleagues examined vitamin D levels in blood twice a year for at least 2 years in 178 people with MS. People with MS on interferon therapy had higher levels of vitamin D than people with MS who were not on interferon. People on interferon synthesized more vitamin D per unit of sun exposure time than those not on interferon. High vitamin D levels were associated with reduced relapse rates only in persons taking interferon. In people with low vitamin D levels, interferon appeared to increase the risk of relapse. (Neurology 2012;79:254-260)
In an accompanying editorial, Alberto Ascherio, MD, DrPH (Harvard Medical School) and Ruth Ann Marrie, MD, PhD, FRCPC (University of Manitoba, Winnipeg) note that the discrepancy between the latter two studies could be explained by differences in latitude (and thus differences in sun exposure) or differences in the timing of vitamin D administration. “In any case, these preliminary findings should be interpreted cautiously,” they write.
The authors comment that while it is “too soon to recommend the use of high-dose vitamin D in clinical practice,” ensuring that people with MS have adequate levels of vitamin D should be part of routine care. “…considering the high prevalence of vitamin D insufficiency and deficiency in persons with MS, the high risk of osteoporosis, and the safety of vitamin D at modest doses, the evidence is sufficient to recommend monitoring of vitamin D levels and supplementation as needed to achieve at least a year-round level of vitamin D sufficiency in persons with MS.”
The National MS Society is funding several projects in this area, including a new clinical trial getting underway to test whether vitamin D can reduce disease activity in people who have MS. In 2011, the Society convened a summit to explore vitamin D trials farther.
Chronic excess vitamin D is associated with side effects, and some people cannot take supplements, so their use should be administered and monitored in consultation with a physician.
about efforts to stop MS in its tracks.