MS Linked to Vitamin D Deficiency
People with a vitamin D deficiency may be more susceptible to developing multiple sclerosis (MS), according to a new study.
The findings suggest the autoimmune condition is strongly associated with genetically lower levels of vitamin D among people of European descent.
“We have provided support for the causality of low vitamin D levels in susceptibility to multiple sclerosis,” says study author Brent Richards, MD, MSc, of McGill University in Montreal, Canada. “These findings suggest that individuals at high risk for MS, such as first-degree family members, should ensure that their vitamin D levels are normal.”
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While a number of genetic and environmental factors influence an individual’s likelihood of developing MS, evidence has been mounting to suggest that a reduced level of vitamin D in the blood is a risk factor for the condition.
Richards and his colleagues conducted a Mendelian randomization study to evaluate whether genetically reduced levels of vitamin D influence the risk of developing MS. They used 25-hydroxyvitamin D concentrations to measure the vitamin D levels of 2,347 patients who were part of the International Multiple Sclerosis Genetics Consortium study, the largest genetic association study of MS to date.
The researchers found significant statistical evidence that genetically lowered vitamin D levels were strongly associated with increased susceptibility to MS among the study participants, all of whom were of European ancestry.
“The importance of these findings may be magnified in high-latitude countries, which have disproportionately higher rates of MS and also higher rates of vitamin D insufficiency,” they wrote.
“Vitamin D insufficiency is very common and returning people to normal vitamin D levels can generally be achieved by taking vitamin D tablets—a relatively simple and safe intervention,” Richards says.
However, the authors emphasize that further investigation is warranted to examine the potential therapeutic benefits vitamin D supplementation may have in preventing the onset and progression of MS.
“We don’t know when vitamin D should be given and at what dose and for how long to prevent MS,” Richards says. “Our findings provide no insight into whether vitamin D can help people who already have MS.”
The authors suggest that additional insights may come from ongoing randomized controlled trials currently assessing the role of vitamin D supplementation in the treatment and prevention of MS.
—Colleen Mullarkey
Reference
Mokry LE, Ross S, Ahmad OS, Forgetta V, Smith GD, Leong A, et al. Vitamin D and risk of multiple sclerosis: A Mendelian randomization study. PLoS Med. 2015 Aug 25;12(8):e1001866. doi: 10.1371/journal.pmed.1001866.