Vitamin A is not associated with exacerbations in multiple sclerosis

- Vitamin A inhibits Th17 cells formation and promotes Treg formation.
- It can therefore be hypothesized to be involved in MS relapse risk.
- We performed a case-control study and a prospective longitudinal study in RRMS patients.
- All-trans-retinol levels were not significantly lower in patients, and were not associated with relapse risk.

BackgroundVitamin 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.ObjectiveTo compare vitamin A levels in MS patients and controls, and to investigate whether vitamin A levels are associated with relapse risk.MethodsIn 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.ResultsMean vitamin A levels were lower in patients (2.16 μmol/l) than in controls (2.44 μmol/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 (<2.9 μmol/l), medium (2.9-3.7 μmol/l) and high level (>3.7 μmol/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).ConclusionWe 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.