Epub: Decard et al. Low vitamin D and elevated immunoreactivity against Epstein-Barr virus before first clinical manifestation of multiple sclerosis. J Neurol Neurosurg Psychiatry. 2012 Aug 11.
Objective: Vitamin D deficiency and Epstein-Barr virus (EBV) infection may be associated with the development of MS. We investigated serum 25-hydroxyvitamin D (25-OH-D) levels and anti-EBV immunoreactivity in 25 individuals before the first clinical manifestation of MS.
Patients and methods: 56 serum samples of 25 individuals who had donated blood prior to the first clinical MS manifestation (clinically isolated syndrome (CIS)) (four male subjects, 21 female subjects, mean age 31.5 years at time of pre-CIS blood sampling; mean age at disease onset 33.4 years) were available, covering an interval of 7.3 years-2 months (mean 31.5 months) before CIS. In 18 of 25 patients serum samples were also obtained after established diagnosis of MS. Longitudinal age- and gender-matched healthy blood donors (four male subjects, 21 female subjects, 39 samples, mean age 32.5 years) served as controls. Serum 25-OH-D was measured by isotope dilution-liquid chromatography-tandem mass spectrometry. 25-OH-D levels were deconvoluted using published seasonal coefficients from a German population. Immunoglobulin G (IgG) against Epstein-Barr virus nuclear antigen-1 (EBNA1) were assessed using commercially available ELISA.
Results: Low 25-OH-D levels were observed during the 24-month pre-CIS interval (47.8 (32.5-77.2) nmol/l, median (IQR); healthy controls: 81.6 (57.7-98.5), p=0.004, however, still higher than after established diagnosis (24.5 (13.7-47.7), p<0 .0001)
This really is a fantastic study. It is hard to get blood samples before someone is diagnosed with MS, but in order to prove causality a risk factor must be present before disease onset (one of the requirements of the Bradford-Hill criteria (one of Prof G’s and more recently one of my heroes). In this study the researchers showed that people who developed MS were much more likely to be vitamin D deficient and have higher titres of EBV (indicative of higher reactivity against the virus). This further shows that both vitamin D deficiency and EBV are important for the disease to develop. Stopping one of them may prevent the disease.