Vitamin d3 concentration correlates with the severity of multiple sclerosis

To investigate the possible association between serum 25(OH) vitamin D3 concentration and the severity of disease in Iranian patients with multiple sclerosis (MS) and to compare this concentration with a matched control group.

This was an analytical cross-sectional study performed at Jondishapour Neurology Clinic in Tehran, Iran. Patients with relapsing-remitting MS were categorized by disease severity: mild [0≤ Expanded Disability Status Scale (EDSS) ≤3], moderate (3.5≤EDSS≤5.5), and severe (6≤EDSS). Serum concentrations of 25(OH) vitamin D3, calcium, phosphorus, magnesium, and parathyroid hormone were measured in 98 MS patients and 17 healthy age- and sex-matched controls. Fisher's exact, Kruskal-Wallis, Mann-Whitney U test, and independent t and Spearman rank correlation tests were used.

Serum 25(OH) vitamin D3 concentration was significantly lower in patients with MS, especially in the severe MS subgroup, compared with healthy controls (P=0.047). There was a statistically significant inverse correlation between 25(OH) vitamin D3 concentration and EDSS score (P=0.049, R=-0.168 by Spearman rank correlation test), which was observed in women only (P=0.044, R=-0.199).

Our findings not only further disclose the lower level of vitamin D in MS patients in comparison with healthy controls, but also support the association between vitamin D and disease severity in MS.