Vitamin D status and effect of interferon-β1a treatment on MRI activity and serum inflammation markers in relapsing-remitting multiple sclerosis.

To explore if vitamin D modulates interferon-β1a treatment effects in relapsing-remitting multiple sclerosis, we examined relationships between serum vitamin D and magnetic resonance imaging (MRI) activity and ten systemic inflammation markers in 88 patients, before and during treatment. Odds ratios for all MRI parameters were negatively associated with vitamin D levels before therapy, but converged to equally low values irrespective of vitamin D status during treatment. During therapy, similar alterations of MRI activity and inflammation markers were found across patients categorized by mean vitamin D values. This suggests that vitamin D status has no major influence on interferon-β1a treatment effects.