title: Vitamin A is not associated with exacerbations in multiple sclerosis.
abstract: BACKGROUND
  Vitamin A is a multifunctional vitamin that can inhibit the formation of Th17 cells, which are probably involved in the development of relapses in MS. Furthermore, it promotes Treg formation. Therefore, vitamin A can be hypothesized to be lower in patients than in healthy controls, and to decrease relapse risk in relapsing-remitting MS (RRMS) patients.
  
  
  OBJECTIVE
  To compare vitamin A levels in MS patients and controls, and to investigate whether vitamin A levels are associated with relapse risk.
  
  
  METHODS
  In a case-control study all-trans-retinol levels were compared between 31 RRMS patients and 29 matched controls. In a prospective longitudinal study in 73 RRMS patients, serum samples for all-trans-retinol measurements were taken every eight weeks. Associations between all-trans-retinol concentrations and relapse rates were calculated using Poisson regression with the individual serum levels as time-dependent variable. Associations between vitamin A and vitamin D were calculated.
  
  
  RESULTS
  Mean vitamin A levels were lower in patients (2.16μmol/l) than in controls (2.44μmol/l) but with borderline significance (p=0.05). In the longitudinal study, during follow-up (mean 1.7 years), 58 patients experienced a total of 139 relapses. Monthly moving averages of all-trans retinol levels were categorized into tertiles: a low (<2.9μmol/l), medium (2.9-3.7μmol/l) and high level (>3.7μmol/l). Relapse rates were not associated with serum all-trans retinol levels (p>0.2), in univariate nor in multivariate analysis. Serum concentrations of all-trans-retinol and 25-OH-vitamin D were positively correlated, although this correlation was weak (r=0.15).
  
  
  CONCLUSIONS
  We did not find evidence for a role for vitamin A in the disease course of RRMS. We did find an association between vitamin A and D levels in the RRMS patients, possibly explained by dietary products that contain both fat-soluble vitamins.
authors: Department of Neurology, MS Centre ErasMS, Erasmus MC, Rotterdam, The Netherlands. Electronic address: r.hintzen@erasmusmc.nl.
authors: T F
authors: TF
authors: Runia
authors: Department of Biostatistics, Erasmus MC, Rotterdam, The Netherlands.
authors: W C J
authors: WC
authors: Hop
authors: Departments of Clinical Chemistry and Internal Medicine, Erasmus MC, Rotterdam, The Netherlands.
authors: Y B
authors: YB
authors: de Rijke
authors: Department of Neurology, MS Centre ErasMS, Erasmus MC, Rotterdam, The Netherlands.
authors: R Q
authors: RQ
authors: Hintzen
keywords: Exacerbations; Immunology; Longitudinal study; Multiple sclerosis; Vitamin A; Vitamin D