This study aimed to evaluate oral and injectable routes in treatment of hypovitaminosis D in multiple sclerosis (MS) patients. The investigators aimed to assess the efficacy of each method, using the same Mega dose of 600 000 IU D3, in achieving normal serum 25(OH)D level, the durability of the response, the practicality and the possible toxicity.

Ultraviolet sunlight is too low to produce adequate amounts of vitamin D3, and vitamin D insufficiency lasting 4 to 6 months of the year at latitudes of ≥42° is common in individuals with low vitamin D intake. Vitamin D has strong immunoregulatory effects, and vitamin D supplementation prevents experimental autoimmune encephalomyelitis (EAE), an autoimmune disease in animals that is used as a model of MS.

Recently, emerging data from epidemiologic studies suggest that vitamin D may play an important role in the progression of the development of MS. A longitudinal study in pediatric MS showed a 34% lower risk of relapse for every 10 ng/ml higher 25-hydroxyvitamin D level. A similar magnitude of reduced relapse risk was later reported in an adult MS cohort. Higher vitamin D levels have also been shown to be associated with less subsequent inflammatory MS activity on brain magnetic resonance imaging (MRI). Finally, studies have demonstrated that patients have lower vitamin D levels during MS relapses.

Inclusion Criteria:

• with serum 25(OH)D3 concentration ≤ 20 ng/ml

Exclusion Criteria:

• hypercalcaemia, primary hyperparathyroidism, Paget disease, thyrotoxicosis, pregnancy, active malignancy, hypercalciuria, history of liver disease, renal insufficiency, clinically apparent malabsorption syndrome, using drugs containing vitamin D products, calcium, estrogen and drugs known to affect vitamin D metabolism (anticonvulsants, glucocorticoids) or receiving any form of supplements containing vitamin D during last 6 months.
• Participants with serum 25(OH)D concentration≥ 20 ng/ml