The aim of this study was to evaluate the concentration of 25(OH)D3 and the indices of calcium and phosphorus metabolism at different times of relapsing-remitting multiple sclerosis (MS). The relationships between the concentrations of 25(OH)D3 and the indices of calcium-phosphate metabolism were determined, depending on the duration of disease and vitamin and unsaturated fatty acids supplementation.

Thirty patients (15 at the early stage and 15 at the advanced stage of MS) were enrolled. Each patient underwent neurological examination; neurological motor disability was defined according to the Expanded Disability Status Scale (EDSS). The results were compared to the values obtained in the control group (15 individuals) selected according to the age of subjects, their residence, ethnicity and gender.

Significantly lower serum concentrations of 25(OH)D3 in MS patients compared to the control group were found. MS patients at the advanced stage of the disease (duration of 5–6 years) had lower 25(OH)D3 concentrations than patients at the early stage of MS. Among patients in an advanced stage of MS, significantly lower levels of 25(OH)D3 were found in women compared to men with a similar level of physical disability.

Lower serum concentrations of 25(OH)D3 in MS patients compared to the control group were found. The lowest concentrations of 25(OH)D3 were found in female patients aged 20–40 and in patients with a longer disease duration without substantial impairment of calcium-phosphate metabolism.