A new study out of Iran has found that vitamin D status correlates with severity of multiple sclerosis in Iranian patients.

There is a well-known link between vitamin D and multiple sclerosis (MS). Studies have shown that getting enough vitamin D throughout life decreases your risk of getting MS. Also, the incidence of MS is higher in countries further from the equator, leading many researchers to believe that sun exposure and vitamin D are protective against MS.

In Iran, despite the country being close to the equator, people dress in heavy clothing, restricting the skin’s ability to produce vitamin D. Thus vitamin D deficiency is much more common in Iran than you might expect. In recent years, researchers have noticed an increase in MS prevalence in the country.

In the present study, researchers out of Shaheed Beheshti University in Iran studied 98 patients with relapsing-remitting MS. They matched these patients with 17 healthy controls. They wanted to know, were MS patients more likely to be deficient in vitamin D compared to controls? In addition, they wanted to know if vitamin D status correlated at all with the disease severity in MS.

They found that in general, MS patients only had slightly lower vitamin D levels than healthy controls, with mean levels of 31.7 ng/ml in MS patients and 35.8 ng/ml in healthy controls.

However, they did find that in patients with MS, the disease severity correlated with vitamin D levels. Those with severe relapsing-remitting MS had mean levels of 21.5 ng/ml, while those with a milder relapsing-remitting MS had mean levels of 33.6 ng/ml.

Lastly, when the researchers assessed each patient’s disability score using the Expanded Disability Status Scale (EDDS), they found that vitamin D status correlated with the score. The worse the EDDS score, the lower the vitamin D score (P=0.049, R=−0.168).

The researchers concluded that there was a lower vitamin D level in MS patients and suggest that vitamin D could be involved in the regulation of clinical disease activity in MS, based on its inverse correlation with disease severity, as measured using the EDSS score.


Vitamin D Council. Vitamin D Newsletter. August 12, 2013.

Shahbeigi S et al. Vitamin D3 Concentration Correlates with the Severity of Multiple Sclerosis. Int J Prev Med, 2013

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