Supplementing our understanding of vitamin D and multiple sclerosis

Therapeutic progress for multiple sclerosis (MS) is accelerating, with several new immunotherapies poised for pivotal randomized controlled trials or regulatory approval. However, when responding to our patients' common query—“Is there anything else I can do, perhaps in my lifestyle or diet, that will change the course of my disease?”—we lack validated, quantitative evidence to guide most interventions. The undeniable role of environmental factors in MS causation suggests that there should also be candidates for lifestyle or dietary manipulation that might alter the natural history of established disease.

Recent epidemiologic work has focused on the independent and combined contributions, including environment-gene interactions, of 3 environmental factors on MS risk and course.^1,2 First, early-life Epstein-Barr virus infection appears to be a necessary, but insufficient, event permitting disease occurrence. However, the evidence regarding persistent CNS infection or lasting viral influence in established MS, which might allow a specific intervention, is conflicting.³ Second, cigarette smoking may increase MS risk as well as the rate of disease progression; these are yet more reasons to counsel cessation. The third factor, vitamin D status, is the most promising environmental candidate that can bind together the various strands of epidemiologic …