Lancet Neurology Review: Vitamin D and Multiple Sclerosis

The authors of this review note that the risk of developing multiple sclerosis (MS) is determined by a combination of genetic and environmental factors; the latter includes inadequate serum concentrations of vitamin D.  As deficiency of vitamin D is endemic worldwide, it is possible that supplementation could result in a reduction in the global burden of MS.

In their review, they analyse the available epidemiological studies on vitamin D and MS risk or severity, and their potential implications for MS prevention and treatment.  The following are covered:

- Background on vitamin D (source and metabolism; non-calcaemic effects)
- Epidemiology (factors affecting exposure, reliability of measures, study design, confounding and bias)
- Vitamin D and MS risk
- Vitamin D and MS activity and progression

In their conclusion, the authors note the following:

• Vitamin D supplementation in healthy individuals is emerging as a promising approach for MS prevention, with a strong suggestion that vitamin D concentrations during late adolescence and young adulthood have a major effect in determining MS risk.

A large randomised trial is needed to establish the safety and efficacy of large-scale vitamin D supplementation in prevention of MS, although this would require the administration of relatively high doses of vitamin D to hundreds of thousands of young adults for several years.

• Evidence supporting a therapeutic effect of vitamin D in modifying the course of MS is less compelling than evidence of a preventive effect. However, there is sufficient evidence to support the need for large randomised trials to determine whether vitamin D supplementation could delay the time to progress from a first demyelinating episode to MS or to MS treatment.

• Screening of serum 25-hydroxyvitamin D concentrations is likely to identify a large proportion of patients who are vitamin D deficient or insufficient, who might benefit from vitamin D supplementation for prevention of osteoporosis and other complications.

The authors of an accompanying commentary comment that trials are required to address the numerous questions that remain in this area.  In the meantime, they suggest that taking steps to tackle vitamin D deficiency in high-risk populations seem warranted.  They say that “Because any benefits for MS in particular will take decades to emerge, a long-term outlook is needed from policy makers, but future health and financial benefits have the potential to make this investment highly rewarding.”

source:

http://www.nelm.nhs.uk/en/NeLM-Area/News/2010—May/24/Review-Vitamin-D-and-multiple-sclerosis/