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Higher 25-hydroxyvitamin D is associated with lower relapse risk in multiple sclerosis†

  1. Steve Simpson Jr. MPH1,
  2. Bruce Taylor MD1,*,
  3. Leigh Blizzard PhD1,
  4. Anne-Louise Ponsonby PhD2,
  5. Fotini Pittas PhD1,
  6. Helen Tremlett PhD3,
  7. Terence Dwyer MD2,
  8. Peter Gies PhD4,
  9. Ingrid van der Mei PhD1

Article first published online: 6 APR 2010

DOI: 10.1002/ana.22043

Issue

Annals of Neurology

Annals of Neurology

Volume 68, Issue 2, pages 193–203, August 2010

Additional Information

How to Cite

Simpson, S., Taylor, B., Blizzard, L., Ponsonby, A.-L., Pittas, F., Tremlett, H., Dwyer, T., Gies, P. and van der Mei, I. (2010), Higher 25-hydroxyvitamin D is associated with lower relapse risk in multiple sclerosis. Ann Neurol., 68: 193–203. doi: 10.1002/ana.22043

Author Information

  1. 1

    Menzies Research Institute Private Bag 23 Hobart TAS 7001 Australia

  2. 2

    Murdoch Children's Research Institute, University of Melbourne, Melbourne, Australia

  3. 3

    Division of Neurology, Faculty of Medicine, University of British Columbia, Vancouver, Canada

  4. 4

    Ultraviolet Radiation Section, Australian Radiation Protection and Nuclear Safety Agency, Yallambie, Australia

*Menzies Research Institute, Australia

  1. †

    This project was approved the Tasmanian Health and Medical Human Research Ethics Committee, H6508.

Publication History

  1. Issue published online: 2 AUG 2010
  2. Article first published online: 6 APR 2010
  3. Manuscript Accepted: 23 MAR 2010
  4. Manuscript Revised: 14 MAR 2010
  5. Manuscript Received: 23 DEC 2009

Funded by

  • National Health and Medical Research Council of Australia. Grant Number: Project 211308
  • Trish Foundation

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Abstract

Objective

A protective association between higher vitamin D levels and the onset of multiple sclerosis (MS) has been demonstrated; however, its role in modulating MS clinical course has been little studied. We investigated whether higher levels of serum 25-hydroxyvitamin D (25-OH-D) were associated with a lower risk of relapses in people with MS.

Methods

We conducted a prospective cohort study of 145 participants with relapsing-remitting MS from 2002 to 2005. Serum 25-OH-D levels were measured biannually, and the hazard of relapse was assessed using survival analysis.

Results

There was an inverse linear relationship between 25-OH-D levels and the hazard of relapse over the subsequent 6 months, with hazard ratio (HR) 0.91 (95% confidence interval [CI]: 0.85–0.97) per 10nmol/l increase in 25-OH-D level (p = 0.006). When variation due to timing of blood collection was removed by estimating 25-OH-D at the start of each season, this association persisted, with HR 0.90 (95% CI, 0.83–0.98) per 10nmol/l increase (p = 0.016). Taking into account the biological half-life of 25-OH-D, we estimated 25-OH-D at monthly intervals, resulting in a slightly enhanced association, with HR 0.88 (95% CI, 0.82–0.95) per 10nmol/l increase (p = 0.001). Adjusting for potential confounders did not alter these findings.

Interpretation

In this prospective population-based cohort study, in a cohort largely on immunomodulatory therapy, higher 25-OH-D levels were associated with a reduced hazard of relapse. This occurred in a dose-dependent linear fashion, with each 10nmol/l increase in 25-OH-D resulting in up to a 12% reduction in risk of relapse. Clinically, raising 25-OH-D levels by 50nmol/l could halve the hazard of a relapse. ANN NEUROL 2010;68:193–203

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