RT Journal Article SR Electronic T1 Vitamin D and disease activity in multiple sclerosis before and during interferon-β treatment JF Neurology JO Neurology FD Lippincott Williams & Wilkins SP WNL.0b013e31825fdf01 DO 10.1212/WNL.0b013e31825fdf01 A1 Løken-Amsrud, Kristin I. A1 Holmøy, Trygve A1 Bakke, Søren J. A1 Beiske, Antonie Giaever A1 Bjerve, Kristian S. A1 Bjørnarå, Bård T. A1 Hovdal, Harald A1 Lilleås, Finn A1 Midgard, Rune A1 Pedersen, Tom A1 Benth, Jurate Šaltytė A1 Sandvik, Leiv A1 Torkildsen, Øivind A1 Wergeland, Stig A1 Myhr, Kjell-Morten YR 2012 UL http://n.neurology.org/content/early/2012/06/13/WNL.0b013e31825fdf01.abstract AB Objective: Studies based on deseasonalized vitamin D levels suggest that vitamin D may influence the disease activity in multiple sclerosis (MS), and high doses are suggested as add-on treatment to interferon-β (IFN-β). Seasonal fluctuation of vitamin D varies between individuals, thus the relationship to disease activity should preferentially be studied by repeated and simultaneous vitamin D and MRI measurements from each patient. Methods: This was a cohort study comprising 88 patients with relapsing-remitting MS who were followed for 6 months with 7 MRI and 4 25-hydroxyvitamin D measurements before initiation of IFN-β, and for 18 months with 5 MRI and 5 25-hydroxyvitamin D measurements during IFN-β treatment. Results: Prior to IFN-β treatment, each 10 nmol/L increase in 25-hydroxyvitamin D was associated with 12.7% (p = 0.037) reduced odds for new T1 gadolinium-enhancing lesions, 11.7% (p = 0.044) for new T2 lesions, and 14.1% (p = 0.024) for combined unique activity. Patients with the most pronounced fluctuation in 25-hydroxyvitamin D displayed larger proportion of MRI scans with new T1 gadolinium-enhancing lesions (51% vs 23%, p = 0.004), combined unique activity (60% vs 32%, p = 0.003), and a trend for new T2 lesions (49% vs 28%, p = 0.052) at the lowest compared to the highest 25-hydroxyvitamin D level. No association between 25-hydroxyvitamin D and disease activity was detected after initiation of IFN-β. HLA-DRB1*15 status did not affect the results. Conclusion: In untreated patients with MS, increasing levels of 25-hydroxyvitamin D are inversely associated with radiologic disease activity irrespective of their HLA-DRB1*15 status.