A new and interesting study supports a causal link in the risk of incidence for multiple sclerosis (MS) in patients with low levels of vitamin D.

There has been a strong relationship between decreased levels of vitamin D and an increased risk of MS, say the researchers from the Department of Medicine, Human Genetics, Epidemiology and Biostatistics, McGill University, Montreal, Quebec, Canada.

This theory provides the rationale to further investigate whether vitamin D supplementation may reduce the incidence of MS among those most at risk.

The vitamin D insufficiency is very common and has been previously associated with an increased risk of multiple sclerosis. However, these results were achieved with scepticism because the levels of vitamin D were associated with many other factors that could really affect the SM.

To overcome these drawbacks, the study was carried out with a new method called “Mendelian randomization”, which uses the natural genetic randomization.

First, the researchers have identified single nucleotide polymorphisms (SNPs) associated with low levels of 25-hydroxyvitamin D using the study data SUNLIGHT, which is the largest genome-wide association study for levels of 25 ( OH) D published to date.

The researchers found that four SNPs located in the genes strongly implicated in influencing the 25 (OH) D had a large genome of importance for the monitoring of the levels of 25 (OH) D.

Next, they determined the effect of these four SNPs on the levels of 25 (OH) D in 2347 participants of the multicentre Canadian study on osteoporosis. They found that each of the SNP was strongly associated with 25 (OH) D below.

Finally, the researchers applied the principles of MendeSlian randomization to study the implication of genetic low levels of 25 (OH) D with risk of MS, using data from the Multiple Sclerosis Genetics Consortium (IMSGC).

They found that each decrease of genetically determined level of 25 (OH) D was associated with a 2-fold increase in the probability of SM.

The optimal levels of vitamin D may delay or prevent its onset MS and warrants further investigations with long-term randomized controlled trials through the use of vitamin D supplementation.